diff --git a/.cargo_vcs_info.json b/.cargo_vcs_info.json
index a7c24e4..4139f46 100644
--- a/.cargo_vcs_info.json
+++ b/.cargo_vcs_info.json
@@ -1,5 +1,5 @@
 {
   "git": {
-    "sha1": "8b22d900058f407646e3c12d353abb890bc78816"
+    "sha1": "50bceff36e169673b49bfffa1809bba6be9bd07f"
   }
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 93532b5..abd9bb5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,45 @@
 
 ## [Unreleased]
 
+## [0.9.5] - 2020-06-24
+
+### Changed
+
+-   Sections of source code that are marked with primary labels are now rendered
+    using the primary highlight color.
+
+## [0.9.4] - 2020-05-18
+
+### Changed
+
+-   We have made the caret rendering easier to read when there are multiple
+    labels on the same line. We also avoid printing trailing borders on the
+    final source source snippet if no notes are present. Instead of this:
+    ```
+       ┌─ one_line.rs:3:5
+       │
+     3 │     v.push(v.pop().unwrap());
+       │     - first borrow later used by call
+       │       ---- first mutable borrow occurs here
+       │            ^ second mutable borrow occurs here
+       │
+    ```
+    …we now render the following:
+    ```
+       ┌─ one_line.rs:3:5
+       │
+     3 │     v.push(v.pop().unwrap());
+       │     - ---- ^ second mutable borrow occurs here
+       │     │ │
+       │     │ first mutable borrow occurs here
+       │     first borrow later used by call
+    ```
+
+### Fixed
+
+-   Diagnostic rendering no longer panics if label ranges are between UTF-8
+    character boundaries.
+
 ## [0.9.3] - 2020-04-29
 
 ### Changed
@@ -206,7 +245,9 @@
 ## [0.2.1] - 2019-02-26
 ## [0.2.0] - 2018-10-11
 
-[Unreleased]: https://github.com/brendanzab/codespan/compare/v0.9.3...HEAD
+[Unreleased]: https://github.com/brendanzab/codespan/compare/v0.9.5...HEAD
+[0.9.4]: https://github.com/brendanzab/codespan/compare/v0.9.4...v0.9.5
+[0.9.4]: https://github.com/brendanzab/codespan/compare/v0.9.3...v0.9.4
 [0.9.3]: https://github.com/brendanzab/codespan/compare/v0.9.2...v0.9.3
 [0.9.2]: https://github.com/brendanzab/codespan/compare/v0.9.1...v0.9.2
 [0.9.1]: https://github.com/brendanzab/codespan/compare/v0.9.0...v0.9.1
diff --git a/Cargo.lock b/Cargo.lock
index e7aed11..e41e6d0 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -11,9 +11,9 @@
 
 [[package]]
 name = "anyhow"
-version = "1.0.28"
+version = "1.0.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d9a60d744a80c30fcb657dfe2c1b22bcb3e814c1a1e3674f32bf5820b570fbff"
+checksum = "85bb70cc08ec97ca5450e6eba421deeea5f172c0fc61f78b5357b2a8e8be195f"
 
 [[package]]
 name = "arrayref"
@@ -69,9 +69,9 @@
 
 [[package]]
 name = "cc"
-version = "1.0.52"
+version = "1.0.54"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c3d87b23d6a92cd03af510a5ade527033f6aa6fa92161e2d5863a907d4c5e31d"
+checksum = "7bbb73db36c1246e9034e307d0fba23f9a2e251faa47ade70c1bd252220c8311"
 
 [[package]]
 name = "cfg-if"
@@ -81,9 +81,9 @@
 
 [[package]]
 name = "clap"
-version = "2.33.0"
+version = "2.33.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5067f5bb2d80ef5d68b4c87db81601f0b75bca627bc2ef76b141d7b846a3c6d9"
+checksum = "bdfa80d47f954d53a35a64987ca1422f495b8d6483c0fe9f7117b36c2a792129"
 dependencies = [
  "ansi_term",
  "atty",
@@ -108,7 +108,7 @@
 
 [[package]]
 name = "codespan-reporting"
-version = "0.9.3"
+version = "0.9.5"
 dependencies = [
  "anyhow",
  "insta",
@@ -161,22 +161,21 @@
 checksum = "524cbf6897b527295dff137cec09ecf3a05f4fddffd7dfcd1585403449e74198"
 
 [[package]]
-name = "dirs"
-version = "2.0.2"
+name = "dirs-next"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "13aea89a5c93364a98e9b37b2fa237effbb694d5cfe01c5b70941f7eb087d5e3"
+checksum = "1cbcf9241d9e8d106295bd496bbe2e9cffd5fa098f2a8c9e2bbcbf09773c11a8"
 dependencies = [
  "cfg-if",
- "dirs-sys",
+ "dirs-sys-next",
 ]
 
 [[package]]
-name = "dirs-sys"
-version = "0.3.4"
+name = "dirs-sys-next"
+version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "afa0b23de8fd801745c471deffa6e12d248f962c9fd4b4c33787b055599bde7b"
+checksum = "9c60f7b8a8953926148223260454befb50c751d3c50e1c178c4fd1ace4083c9a"
 dependencies = [
- "cfg-if",
  "libc",
  "redox_users",
  "winapi",
@@ -184,9 +183,9 @@
 
 [[package]]
 name = "dtoa"
-version = "0.4.5"
+version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4358a9e11b9a09cf52383b451b49a169e8d797b68aa02301ff586d70d9661ea3"
+checksum = "134951f4028bdadb9b84baf4232681efbf277da25144b9b0ad65df75946c422b"
 
 [[package]]
 name = "encode_unicode"
@@ -216,9 +215,9 @@
 
 [[package]]
 name = "hermit-abi"
-version = "0.1.12"
+version = "0.1.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "61565ff7aaace3525556587bd2dc31d4a07071957be715e63ce7b1eccf51a8f4"
+checksum = "b9586eedd4ce6b3c498bc3b4dd92fc9f11166aa908a914071953768066c67909"
 dependencies = [
  "libc",
 ]
@@ -239,9 +238,9 @@
 
 [[package]]
 name = "itoa"
-version = "0.4.5"
+version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b8b7a7c0c47db5545ed3fef7468ee7bb5b74691498139e4b3f6a20685dc6dd8e"
+checksum = "dc6f3ad7b9d11a0c00842ff8de1b60ee58661048eb8049ed33c73594f359d7e6"
 
 [[package]]
 name = "lazy_static"
@@ -251,15 +250,15 @@
 
 [[package]]
 name = "libc"
-version = "0.2.69"
+version = "0.2.71"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "99e85c08494b21a9054e7fe1374a732aeadaff3980b6990b94bfd3a70f690005"
+checksum = "9457b06509d27052635f90d6466700c65095fdf75409b3fbdd903e988b886f49"
 
 [[package]]
 name = "linked-hash-map"
-version = "0.5.2"
+version = "0.5.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae91b68aebc4ddb91978b11a1b02ddd8602a05ec19002801c5666000e05e0f83"
+checksum = "8dd5a6d5999d9907cda8ed67bbd137d3af8085216c2ac62de5be860bd41f304a"
 
 [[package]]
 name = "log"
@@ -344,18 +343,18 @@
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.10"
+version = "1.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "df246d292ff63439fea9bc8c0a270bed0e390d5ebd4db4ba15aba81111b5abe3"
+checksum = "beae6331a816b1f65d04c45b078fd8e6c93e8071771f41b8163255bbd8d7c8fa"
 dependencies = [
  "unicode-xid",
 ]
 
 [[package]]
 name = "quote"
-version = "1.0.3"
+version = "1.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2bdc6c187c65bca4260c9011c9e3132efe4909da44726bad24cf7572ae338d7f"
+checksum = "aa563d17ecb180e500da1cfd2b028310ac758de548efdd203e18f283af693f37"
 dependencies = [
  "proc-macro2",
 ]
@@ -391,12 +390,12 @@
 
 [[package]]
 name = "rustyline"
-version = "6.1.2"
+version = "6.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1cd20b28d972040c627e209eb29f19c24a71a19d661cc5a220089176e20ee202"
+checksum = "3358c21cbbc1a751892528db4e1de4b7a2b6a73f001e215aaba97d712cfa9777"
 dependencies = [
  "cfg-if",
- "dirs",
+ "dirs-next",
  "libc",
  "log",
  "memchr",
@@ -410,9 +409,9 @@
 
 [[package]]
 name = "ryu"
-version = "1.0.4"
+version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ed3d612bc64430efeb3f7ee6ef26d590dce0c43249217bddc62112540c7941e1"
+checksum = "71d301d4193d031abdd79ff7e3dd721168a9572ef3fe51a1517aba235bd8f86e"
 
 [[package]]
 name = "scopeguard"
@@ -422,18 +421,18 @@
 
 [[package]]
 name = "serde"
-version = "1.0.106"
+version = "1.0.114"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "36df6ac6412072f67cf767ebbde4133a5b2e88e76dc6187fa7104cd16f783399"
+checksum = "5317f7588f0a5078ee60ef675ef96735a1442132dc645eb1d12c018620ed8cd3"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.106"
+version = "1.0.114"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9e549e3abf4fb8621bd1609f11dfc9f5e50320802273b12f3811a67e6716ea6c"
+checksum = "2a0be94b04690fbaed37cddffc5c134bf537c8e3329d53e982fe04c374978f8e"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -442,9 +441,9 @@
 
 [[package]]
 name = "serde_json"
-version = "1.0.52"
+version = "1.0.55"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a7894c8ed05b7a3a279aeb79025fdec1d3158080b75b98a08faf2806bb799edd"
+checksum = "ec2c5d7e739bc07a3e73381a39d61fdb5f671c60c1df26a130690665803d8226"
 dependencies = [
  "itoa",
  "ryu",
@@ -453,9 +452,9 @@
 
 [[package]]
 name = "serde_yaml"
-version = "0.8.11"
+version = "0.8.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "691b17f19fc1ec9d94ec0b5864859290dff279dbd7b03f017afda54eb36c3c35"
+checksum = "ae3e2dd40a7cdc18ca80db804b7f461a39bb721160a85c9a1fa30134bf3c02a5"
 dependencies = [
  "dtoa",
  "linked-hash-map",
@@ -471,9 +470,9 @@
 
 [[package]]
 name = "structopt"
-version = "0.3.14"
+version = "0.3.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "863246aaf5ddd0d6928dfeb1a9ca65f505599e4e1b399935ef7e75107516b4ef"
+checksum = "de2f5e239ee807089b62adce73e48c625e0ed80df02c7ab3f068f5db5281065c"
 dependencies = [
  "clap",
  "lazy_static",
@@ -482,9 +481,9 @@
 
 [[package]]
 name = "structopt-derive"
-version = "0.4.7"
+version = "0.4.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d239ca4b13aee7a2142e6795cbd69e457665ff8037aed33b3effdc430d2f927a"
+checksum = "510413f9de616762a4fbeab62509bf15c729603b72d7cd71280fbca431b1c118"
 dependencies = [
  "heck",
  "proc-macro-error",
@@ -495,9 +494,9 @@
 
 [[package]]
 name = "syn"
-version = "1.0.18"
+version = "1.0.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "410a7488c0a728c7ceb4ad59b9567eb4053d02e8cc7f5c0e0eeeb39518369213"
+checksum = "e8d5d96e8cbb005d6959f119f773bfaebb5684296108fb32600c00cde305b2cd"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -572,9 +571,9 @@
 
 [[package]]
 name = "unindent"
-version = "0.1.5"
+version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "63f18aa3b0e35fed5a0048f029558b1518095ffe2a0a31fb87c93dece93a4993"
+checksum = "af41d708427f8fd0e915dcebb2cae0f0e6acb2a939b2d399c265c39a38a18942"
 
 [[package]]
 name = "utf8parse"
@@ -584,15 +583,15 @@
 
 [[package]]
 name = "vec_map"
-version = "0.8.1"
+version = "0.8.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "05c78687fb1a80548ae3250346c3db86a80a7cdd77bda190189f2d0a0987c81a"
+checksum = "f1bddf1187be692e79c5ffeab891132dfb0f236ed36a43c7ed39f1165ee20191"
 
 [[package]]
 name = "version_check"
-version = "0.9.1"
+version = "0.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "078775d0255232fb988e6fccf26ddc9d1ac274299aaedcedce21c6f72cc533ce"
+checksum = "b5a972e5669d67ba988ce3dc826706fb0a8b01471c088cb0b6110b805cc36aed"
 
 [[package]]
 name = "void"
@@ -639,9 +638,9 @@
 
 [[package]]
 name = "yaml-rust"
-version = "0.4.3"
+version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "65923dd1784f44da1d2c3dbbc5e822045628c590ba72123e1c73d3c230c4434d"
+checksum = "39f0c922f1a334134dc2f7a8b67dc5d25f0735263feec974345ff706bcf20b0d"
 dependencies = [
  "linked-hash-map",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index e55a44f..294d127 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,7 +13,7 @@
 [package]
 edition = "2018"
 name = "codespan-reporting"
-version = "0.9.3"
+version = "0.9.5"
 authors = ["Brendan Zabarauskas <bjzaba@yahoo.com.au>"]
 exclude = ["assets/**"]
 description = "Beautiful diagnostic reporting for text-based programming languages"
diff --git a/Cargo.toml.orig b/Cargo.toml.orig
index f7bb15f..427e854 100644
--- a/Cargo.toml.orig
+++ b/Cargo.toml.orig
@@ -1,6 +1,6 @@
 [package]
 name = "codespan-reporting"
-version = "0.9.3"
+version = "0.9.5"
 readme = "../README.md"
 license = "Apache-2.0"
 authors = ["Brendan Zabarauskas <bjzaba@yahoo.com.au>"]
diff --git a/METADATA b/METADATA
index 5033068..56c195b 100644
--- a/METADATA
+++ b/METADATA
@@ -1,7 +1,5 @@
 name: "codespan-reporting"
-description:
-    "Beautiful diagnostic reporting for text-based programming languages."
-
+description: "Beautiful diagnostic reporting for text-based programming languages."
 third_party {
   url {
     type: HOMEPAGE
@@ -11,7 +9,11 @@
     type: GIT
     value: "https://github.com/brendanzab/codespan"
   }
-  version: "0.9.3"
-  last_upgrade_date { year: 2020 month: 5 day: 11 }
+  version: "0.9.5"
   license_type: NOTICE
+  last_upgrade_date {
+    year: 2020
+    month: 7
+    day: 10
+  }
 }
diff --git a/src/diagnostic.rs b/src/diagnostic.rs
index 6655a91..559c899 100644
--- a/src/diagnostic.rs
+++ b/src/diagnostic.rs
@@ -67,7 +67,7 @@
     pub style: LabelStyle,
     /// The file that we are labelling.
     pub file_id: FileId,
-    /// The range we are going to include in the final snippet.
+    /// The range in bytes we are going to include in the final snippet.
     pub range: Range<usize>,
     /// An optional message to provide some additional information for the
     /// underlined code. These should not include line breaks.
diff --git a/src/files.rs b/src/files.rs
index a717555..41691b9 100644
--- a/src/files.rs
+++ b/src/files.rs
@@ -191,6 +191,7 @@
 ///
 /// assert_eq!(line_index(&line_starts, 5), Some(1));
 /// ```
+// NOTE: this is copied in `codespan::file::line_starts` and should be kept in sync.
 pub fn line_starts<'source>(source: &'source str) -> impl 'source + Iterator<Item = usize> {
     std::iter::once(0).chain(source.match_indices('\n').map(|(i, _)| i + 1))
 }
diff --git a/src/term/config.rs b/src/term/config.rs
index a3bd03a..7b834d7 100644
--- a/src/term/config.rs
+++ b/src/term/config.rs
@@ -1,4 +1,3 @@
-use std::io;
 use termcolor::{Color, ColorSpec};
 
 use crate::diagnostic::{LabelStyle, Severity};
@@ -31,58 +30,6 @@
     }
 }
 
-impl Config {
-    /// Measure the width of a string, taking into account the tab width.
-    pub fn width(&self, s: &str) -> usize {
-        use unicode_width::UnicodeWidthChar;
-
-        s.chars()
-            .map(|ch| match ch {
-                '\t' => self.tab_width,
-                _ => ch.width().unwrap_or(0),
-            })
-            .sum()
-    }
-
-    /// Construct a source writer using the current config.
-    pub fn source<'a, W: ?Sized>(&self, writer: &'a mut W) -> SourceWriter<&'a mut W> {
-        SourceWriter {
-            upstream: writer,
-            tab_width: self.tab_width,
-        }
-    }
-}
-
-/// Writer that replaces tab characters with the configured number of spaces.
-pub struct SourceWriter<W> {
-    upstream: W,
-    tab_width: usize,
-}
-
-impl<W: io::Write> io::Write for SourceWriter<W> {
-    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        let mut last_term = 0usize;
-        for (i, ch) in buf.iter().enumerate() {
-            if *ch == b'\t' {
-                self.upstream.write_all(&buf[last_term..i])?;
-                last_term = i + 1;
-                write!(
-                    self.upstream,
-                    "{space: >width$}",
-                    space = "",
-                    width = self.tab_width,
-                )?;
-            }
-        }
-        self.upstream.write_all(&buf[last_term..])?;
-        Ok(buf.len())
-    }
-
-    fn flush(&mut self) -> io::Result<()> {
-        self.upstream.flush()
-    }
-}
-
 /// The display style to use when rendering diagnostics.
 #[derive(Clone, Debug)]
 pub enum DisplayStyle {
@@ -279,29 +226,10 @@
     /// The character to use for the left of a multi-line label.
     /// Defaults to: `'│'`.
     pub multi_left: char,
-}
 
-impl Chars {
-    pub fn single_caret_char(&self, label_style: LabelStyle) -> char {
-        match label_style {
-            LabelStyle::Primary => self.single_primary_caret,
-            LabelStyle::Secondary => self.single_secondary_caret,
-        }
-    }
-
-    pub fn multi_caret_char_start(&self, label_style: LabelStyle) -> char {
-        match label_style {
-            LabelStyle::Primary => self.multi_primary_caret_start,
-            LabelStyle::Secondary => self.multi_secondary_caret_start,
-        }
-    }
-
-    pub fn multi_caret_char_end(&self, label_style: LabelStyle) -> char {
-        match label_style {
-            LabelStyle::Primary => self.multi_primary_caret_end,
-            LabelStyle::Secondary => self.multi_secondary_caret_end,
-        }
-    }
+    /// The character to use for the left of a pointer underneath a caret.
+    /// Defaults to: `'│'`.
+    pub pointer_left: char,
 }
 
 impl Default for Chars {
@@ -326,6 +254,8 @@
             multi_bottom_left: '╰',
             multi_bottom: '─',
             multi_left: '│',
+
+            pointer_left: '│',
         }
     }
 }
diff --git a/src/term/renderer.rs b/src/term/renderer.rs
index a8b8601..ab5656e 100644
--- a/src/term/renderer.rs
+++ b/src/term/renderer.rs
@@ -30,25 +30,25 @@
     /// ```text
     /// ╭
     /// ```
-    TopLeft(LabelStyle),
+    TopLeft,
     /// Multi-line label top.
     ///
     /// ```text
     /// ╭────────────^
     /// ```
-    Top(LabelStyle, RangeTo<usize>),
+    Top(RangeTo<usize>),
     /// Left vertical labels for multi-line labels.
     ///
     /// ```text
     /// │
     /// ```
-    Left(LabelStyle),
+    Left,
     /// Multi-line label bottom, with an optional message.
     ///
     /// ```text
     /// ╰────────────^ blah blah
     /// ```
-    Bottom(LabelStyle, RangeTo<usize>, &'diagnostic str),
+    Bottom(RangeTo<usize>, &'diagnostic str),
 }
 
 #[derive(Copy, Clone)]
@@ -71,7 +71,6 @@
 ///                     │ │ │   │                                                                │
 ///                  ┌────────────────────────────────────────────────────────────────────────────
 ///        header ── │ error[0001]: oh noes, a cupcake has occurred!
-///         empty ── │
 /// snippet start ── │    ┌─ test:9:0
 /// snippet empty ── │    │
 ///  snippet line ── │  9 │   ╭ Cupcake ipsum dolor. Sit amet marshmallow topping cheesecake
@@ -84,8 +83,10 @@
 /// snippet break ── │    · │
 ///  snippet line ── │ 38 │ │   Brownie lemon drops chocolate jelly-o candy canes. Danish marzipan
 ///  snippet line ── │ 39 │ │   jujubes soufflé carrot cake marshmallow tiramisu caramels candy canes.
-///                  │    │ │           ^^^^^^^^^^^^^^^^^^ blah blah
-///                  │    │ │                               -------------------- blah blah
+///                  │    │ │           ^^^^^^^^^^^^^^^^^^^ -------------------- blah blah
+///                  │    │ │           │
+///                  │    │ │           blah blah
+///                  │    │ │           note: this is a note
 ///  snippet line ── │ 40 │ │   Fruitcake jelly-o danish toffee. Tootsie roll pastry cheesecake
 ///  snippet line ── │ 41 │ │   soufflé marzipan. Chocolate bar oat cake jujubes lollipop pastry
 ///  snippet line ── │ 42 │ │   cupcake. Candy canes cupcake toffee gingerbread candy canes muffin
@@ -227,8 +228,12 @@
         severity: Severity,
         single_labels: &[SingleLabel<'_>],
         num_multi_labels: usize,
-        multi_labels: &[(usize, MultiLabel<'_>)],
+        multi_labels: &[(usize, LabelStyle, MultiLabel<'_>)],
     ) -> io::Result<()> {
+        // Trim trailing newlines, linefeeds, and null chars from source, if they exist.
+        // FIXME: Use the number of trimmed placeholders when rendering single line carets
+        let source = source.trim_end_matches(['\n', '\r', '\0'].as_ref());
+
         // Write source line
         //
         // ```text
@@ -243,37 +248,272 @@
             let mut multi_labels_iter = multi_labels.iter().peekable();
             for label_column in 0..num_multi_labels {
                 match multi_labels_iter.peek() {
-                    Some((label_index, label)) if *label_index == label_column => {
+                    Some((label_index, label_style, label)) if *label_index == label_column => {
                         match label {
-                            MultiLabel::TopLeft(label_style) => {
+                            MultiLabel::TopLeft => {
                                 self.label_multi_top_left(severity, *label_style)?;
                             }
                             MultiLabel::Top(..) => self.inner_gutter_space()?,
-                            MultiLabel::Left(label_style) | MultiLabel::Bottom(label_style, ..) => {
+                            MultiLabel::Left | MultiLabel::Bottom(..) => {
                                 self.label_multi_left(severity, *label_style, None)?;
                             }
                         }
                         multi_labels_iter.next();
                     }
-                    Some((_, _)) | None => self.inner_gutter_space()?,
+                    Some((_, _, _)) | None => self.inner_gutter_space()?,
                 }
             }
 
-            // Write source
-            write!(self.config.source(self.writer), " {}", source.trim_end())?;
+            // Write source text
+            write!(self, " ")?;
+            let mut in_primary = false;
+            for (metrics, ch) in self.char_metrics(source.char_indices()) {
+                let column_range = metrics.byte_index..(metrics.byte_index + ch.len_utf8());
+
+                // Check if we are overlapping a primary label
+                let is_primary = single_labels.iter().any(|(ls, range, _)| {
+                    *ls == LabelStyle::Primary && is_overlapping(range, &column_range)
+                }) || multi_labels.iter().any(|(_, ls, label)| {
+                    *ls == LabelStyle::Primary
+                        && match label {
+                            MultiLabel::Top(range) => column_range.start >= range.end,
+                            MultiLabel::TopLeft | MultiLabel::Left => true,
+                            MultiLabel::Bottom(range, _) => column_range.end <= range.end,
+                        }
+                });
+
+                // Set the source color if we are in a primary label
+                if is_primary && !in_primary {
+                    self.set_color(self.styles().label(severity, LabelStyle::Primary))?;
+                    in_primary = true;
+                } else if !is_primary && in_primary {
+                    self.reset()?;
+                    in_primary = false;
+                }
+
+                match ch {
+                    '\t' => (0..metrics.unicode_width).try_for_each(|_| write!(self, " "))?,
+                    _ => write!(self, "{}", ch)?,
+                }
+            }
+            if in_primary {
+                self.reset()?;
+            }
             write!(self, "\n")?;
         }
 
         // Write single labels underneath source
         //
         // ```text
-        //     │ │   │    ^^^^ oh noes
+        //   │     - ---- ^^^ second mutable borrow occurs here
+        //   │     │ │
+        //   │     │ first mutable borrow occurs here
+        //   │     first borrow later used by call
+        //   │     help: some help here
         // ```
-        for (label_style, range, message) in single_labels.iter() {
+        if !single_labels.is_empty() {
+            // Our plan is as follows:
+            //
+            // 1. Do an initial scan to find:
+            //    - The number of non-empty messages.
+            //    - The right-most start and end positions of labels.
+            //    - A candidate for a trailing label (where the label's message
+            //      is printed to the left of the caret).
+            // 2. Check if the trailing label candidate overlaps another label -
+            //    if so we print it underneath the carets with the other labels.
+            // 3. Print a line of carets, and (possibly) the trailing message
+            //    to the left.
+            // 4. Print vertical lines pointing to the carets, and the messages
+            //    for those carets.
+            //
+            // We try our best avoid introducing new dynamic allocations,
+            // instead preferring to iterate over the labels multiple times. It
+            // is unclear what the performance tradeoffs are however, so further
+            // investigation may be required.
+
+            // The number of non-empty messages to print.
+            let mut num_messages = 0;
+            // The right-most start position, eg:
+            //
+            // ```text
+            // -^^^^---- ^^^^^^^
+            //           │
+            //           right-most start position
+            // ```
+            let mut max_label_start = 0;
+            // The right-most end position, eg:
+            //
+            // ```text
+            // -^^^^---- ^^^^^^^
+            //                 │
+            //                 right-most end position
+            // ```
+            let mut max_label_end = 0;
+            // A trailing message, eg:
+            //
+            // ```text
+            // ^^^ second mutable borrow occurs here
+            // ```
+            let mut trailing_label = None;
+
+            for (label_index, label) in single_labels.iter().enumerate() {
+                let (_, range, message) = label;
+                if !message.is_empty() {
+                    num_messages += 1;
+                }
+                max_label_start = std::cmp::max(max_label_start, range.start);
+                max_label_end = std::cmp::max(max_label_end, range.end);
+                // This is a candidate for the trailing label, so let's record it.
+                if range.end == max_label_end {
+                    if message.is_empty() {
+                        trailing_label = None;
+                    } else {
+                        trailing_label = Some((label_index, label));
+                    }
+                }
+            }
+            if let Some((trailing_label_index, (_, trailing_range, _))) = trailing_label {
+                // Check to see if the trailing label candidate overlaps any of
+                // the other labels on the current line.
+                if single_labels
+                    .iter()
+                    .enumerate()
+                    .filter(|(label_index, _)| *label_index != trailing_label_index)
+                    .any(|(_, (_, range, _))| is_overlapping(trailing_range, range))
+                {
+                    // If it does, we'll instead want to render it below the
+                    // carets along with the other hanging labels.
+                    trailing_label = None;
+                }
+            }
+
+            // Write a line of carets
+            //
+            // ```text
+            //   │ ^^^^^^  -------^^^^^^^^^-------^^^^^----- ^^^^ trailing label message
+            // ```
             self.outer_gutter(outer_padding)?;
             self.border_left()?;
             self.inner_gutter(severity, num_multi_labels, multi_labels)?;
-            self.label_single(severity, *label_style, source, range.clone(), message)?;
+            write!(self, " ")?;
+
+            let mut previous_label_style = None;
+            let placeholder_metrics = Metrics {
+                byte_index: source.len(),
+                unicode_width: 1,
+            };
+            for (metrics, ch) in self
+                .char_metrics(source.char_indices())
+                // Add a placeholder source column at the end to allow for
+                // printing carets at the end of lines, eg:
+                //
+                // ```text
+                // 1 │ Hello world!
+                //   │             ^
+                // ```
+                .chain(std::iter::once((placeholder_metrics, '\0')))
+            {
+                // Find the current label style at this column
+                let column_range = metrics.byte_index..(metrics.byte_index + ch.len_utf8());
+                let current_label_style = single_labels
+                    .iter()
+                    .filter(|(_, range, _)| is_overlapping(range, &column_range))
+                    .map(|(label_style, _, _)| *label_style)
+                    .max_by_key(label_priority_key);
+
+                // Update writer style if necessary
+                if previous_label_style != current_label_style {
+                    match current_label_style {
+                        None => self.reset()?,
+                        Some(label_style) => {
+                            self.set_color(self.styles().label(severity, label_style))?;
+                        }
+                    }
+                }
+
+                let caret_ch = match current_label_style {
+                    Some(LabelStyle::Primary) => Some(self.chars().single_primary_caret),
+                    Some(LabelStyle::Secondary) => Some(self.chars().single_secondary_caret),
+                    // Only print padding if we are before the end of the last single line caret
+                    None if metrics.byte_index < max_label_end => Some(' '),
+                    None => None,
+                };
+                if let Some(caret_ch) = caret_ch {
+                    // FIXME: improve rendering of carets between character boundaries
+                    (0..metrics.unicode_width).try_for_each(|_| write!(self, "{}", caret_ch))?;
+                }
+
+                previous_label_style = current_label_style;
+            }
+            // Reset style if it was previously set
+            if previous_label_style.is_some() {
+                self.reset()?;
+            }
+            // Write first trailing label message
+            if let Some((_, (label_style, _, message))) = trailing_label {
+                write!(self, " ")?;
+                self.set_color(self.styles().label(severity, *label_style))?;
+                write!(self, "{}", message)?;
+                self.reset()?;
+            }
+            write!(self, "\n")?;
+
+            // Write hanging labels pointing to carets
+            //
+            // ```text
+            //   │     │ │
+            //   │     │ first mutable borrow occurs here
+            //   │     first borrow later used by call
+            //   │     help: some help here
+            // ```
+            if num_messages > trailing_label.iter().count() {
+                // Write first set of vertical lines before hanging labels
+                //
+                // ```text
+                //   │     │ │
+                // ```
+                self.outer_gutter(outer_padding)?;
+                self.border_left()?;
+                self.inner_gutter(severity, num_multi_labels, multi_labels)?;
+                write!(self, " ")?;
+                self.caret_pointers(
+                    severity,
+                    max_label_start,
+                    single_labels,
+                    trailing_label,
+                    source.char_indices(),
+                )?;
+                write!(self, "\n")?;
+
+                // Write hanging labels pointing to carets
+                //
+                // ```text
+                //   │     │ first mutable borrow occurs here
+                //   │     first borrow later used by call
+                //   │     help: some help here
+                // ```
+                for (label_style, range, message) in
+                    hanging_labels(single_labels, trailing_label).rev()
+                {
+                    self.outer_gutter(outer_padding)?;
+                    self.border_left()?;
+                    self.inner_gutter(severity, num_multi_labels, multi_labels)?;
+                    write!(self, " ")?;
+                    self.caret_pointers(
+                        severity,
+                        max_label_start,
+                        single_labels,
+                        trailing_label,
+                        source
+                            .char_indices()
+                            .take_while(|(byte_index, _)| *byte_index < range.start),
+                    )?;
+                    self.set_color(self.styles().label(severity, *label_style))?;
+                    write!(self, "{}", message)?;
+                    self.reset()?;
+                    write!(self, "\n")?;
+                }
+            }
         }
 
         // Write top or bottom label carets underneath source
@@ -282,11 +522,11 @@
         //     │ ╰───│──────────────────^ woops
         //     │   ╭─│─────────^
         // ```
-        for (multi_label_index, (_, label)) in multi_labels.iter().enumerate() {
+        for (multi_label_index, (_, label_style, label)) in multi_labels.iter().enumerate() {
             let (label_style, range, bottom_message) = match label {
-                MultiLabel::TopLeft(_) | MultiLabel::Left(_) => continue, // no label caret needed
-                MultiLabel::Top(ls, range) => (*ls, range, None),
-                MultiLabel::Bottom(ls, range, message) => (*ls, range, Some(message)),
+                MultiLabel::TopLeft | MultiLabel::Left => continue, // no label caret needed
+                MultiLabel::Top(range) => (*label_style, range, None),
+                MultiLabel::Bottom(range, message) => (*label_style, range, Some(message)),
             };
 
             self.outer_gutter(outer_padding)?;
@@ -301,22 +541,22 @@
             let mut multi_labels_iter = multi_labels.iter().enumerate().peekable();
             for label_column in 0..num_multi_labels {
                 match multi_labels_iter.peek() {
-                    Some((i, (label_index, label))) if *label_index == label_column => {
+                    Some((i, (label_index, ls, label))) if *label_index == label_column => {
                         match label {
-                            MultiLabel::TopLeft(ls) | MultiLabel::Left(ls) => {
+                            MultiLabel::TopLeft | MultiLabel::Left => {
                                 self.label_multi_left(severity, *ls, underline.map(|(s, _)| s))?;
                             }
-                            MultiLabel::Top(ls, ..) if multi_label_index > *i => {
+                            MultiLabel::Top(..) if multi_label_index > *i => {
                                 self.label_multi_left(severity, *ls, underline.map(|(s, _)| s))?;
                             }
-                            MultiLabel::Bottom(ls, ..) if multi_label_index < *i => {
+                            MultiLabel::Bottom(..) if multi_label_index < *i => {
                                 self.label_multi_left(severity, *ls, underline.map(|(s, _)| s))?;
                             }
-                            MultiLabel::Top(ls, ..) if multi_label_index == *i => {
+                            MultiLabel::Top(..) if multi_label_index == *i => {
                                 underline = Some((*ls, VerticalBound::Top));
                                 self.label_multi_top_left(severity, label_style)?
                             }
-                            MultiLabel::Bottom(ls, ..) if multi_label_index == *i => {
+                            MultiLabel::Bottom(..) if multi_label_index == *i => {
                                 underline = Some((*ls, VerticalBound::Bottom));
                                 self.label_multi_bottom_left(severity, label_style)?;
                             }
@@ -353,7 +593,7 @@
         outer_padding: usize,
         severity: Severity,
         num_multi_labels: usize,
-        multi_labels: &[(usize, MultiLabel<'_>)],
+        multi_labels: &[(usize, LabelStyle, MultiLabel<'_>)],
     ) -> io::Result<()> {
         self.outer_gutter(outer_padding)?;
         self.border_left()?;
@@ -372,7 +612,7 @@
         outer_padding: usize,
         severity: Severity,
         num_multi_labels: usize,
-        multi_labels: &[(usize, MultiLabel<'_>)],
+        multi_labels: &[(usize, LabelStyle, MultiLabel<'_>)],
     ) -> io::Result<()> {
         self.outer_gutter(outer_padding)?;
         self.border_left_break()?;
@@ -406,12 +646,39 @@
         Ok(())
     }
 
+    /// Adds tab-stop aware unicode-width computations to an iterator over
+    /// character indices. Assumes that the character indices begin at the start
+    /// of the line.
+    fn char_metrics(
+        &self,
+        char_indices: impl Iterator<Item = (usize, char)>,
+    ) -> impl Iterator<Item = (Metrics, char)> {
+        use unicode_width::UnicodeWidthChar;
+
+        let tab_width = self.config.tab_width;
+        let mut unicode_column = 0;
+
+        char_indices.map(move |(byte_index, ch)| {
+            let metrics = Metrics {
+                byte_index,
+                unicode_width: match (ch, tab_width) {
+                    ('\t', 0) => 0, // Guard divide-by-zero
+                    ('\t', _) => tab_width - (unicode_column % tab_width),
+                    (ch, _) => ch.width().unwrap_or(0),
+                },
+            };
+            unicode_column += metrics.unicode_width;
+
+            (metrics, ch)
+        })
+    }
+
     /// Location focus.
     fn snippet_locus(&mut self, locus: &Locus) -> io::Result<()> {
         write!(
             self,
-            "{origin}:{line_number}:{column_number}",
-            origin = locus.name,
+            "{name}:{line_number}:{column_number}",
+            name = locus.name,
             line_number = locus.location.line_number,
             column_number = locus.location.column_number,
         )
@@ -419,7 +686,7 @@
 
     /// The outer gutter of a source line.
     fn outer_gutter(&mut self, outer_padding: usize) -> io::Result<()> {
-        write!(self, "{space: >width$}", space = "", width = outer_padding,)?;
+        write!(self, "{space: >width$}", space = "", width = outer_padding)?;
         write!(self, " ")?;
         Ok(())
     }
@@ -454,34 +721,37 @@
         Ok(())
     }
 
-    /// Single-line label with a message.
-    ///
-    /// ```text
-    /// ^^ expected `Int` but found `String`
-    /// ```
-    fn label_single(
+    /// Write vertical lines pointing to carets.
+    fn caret_pointers(
         &mut self,
         severity: Severity,
-        label_style: LabelStyle,
-        source: &str,
-        range: Range<usize>,
-        message: &str,
+        max_label_start: usize,
+        single_labels: &[SingleLabel<'_>],
+        trailing_label: Option<(usize, &SingleLabel<'_>)>,
+        char_indices: impl Iterator<Item = (usize, char)>,
     ) -> io::Result<()> {
-        let space_source = slice_at_char_boundaries(source, 0..range.start);
-        let space_len = self.config.width(space_source);
-        write!(self, " {space: >width$}", space = "", width = space_len)?;
-        self.set_color(self.styles().label(severity, label_style))?;
-        let source = slice_at_char_boundaries(source, range);
-        // We use `usize::max` here to ensure that we print at least one
-        // label character - even when we have a zero-length span.
-        for _ in 0..usize::max(self.config.width(source), 1) {
-            write!(self, "{}", self.chars().single_caret_char(label_style))?;
+        for (metrics, ch) in self.char_metrics(char_indices) {
+            let column_range = metrics.byte_index..(metrics.byte_index + ch.len_utf8());
+            let label_style = hanging_labels(single_labels, trailing_label)
+                .filter(|(_, range, _)| column_range.contains(&range.start))
+                .map(|(label_style, _, _)| *label_style)
+                .max_by_key(label_priority_key);
+
+            let mut spaces = match label_style {
+                None => 0..metrics.unicode_width,
+                Some(label_style) => {
+                    self.set_color(self.styles().label(severity, label_style))?;
+                    write!(self, "{}", self.chars().pointer_left)?;
+                    self.reset()?;
+                    1..metrics.unicode_width
+                }
+            };
+            // Only print padding if we are before the end of the last single line caret
+            if metrics.byte_index <= max_label_start {
+                spaces.try_for_each(|_| write!(self, " "))?;
+            }
         }
-        if !message.is_empty() {
-            write!(self, " {}", message)?;
-        }
-        self.reset()?;
-        write!(self, "\n")?;
+
         Ok(())
     }
 
@@ -511,36 +781,6 @@
         Ok(())
     }
 
-    /// The top of a multi-line label.
-    fn label_multi_top_line(
-        &mut self,
-        severity: Severity,
-        label_style: LabelStyle,
-        len: usize,
-    ) -> io::Result<()> {
-        self.set_color(self.styles().label(severity, label_style))?;
-        for _ in 0..len {
-            write!(self, "{}", self.config.chars.multi_top)?;
-        }
-        self.reset()?;
-        Ok(())
-    }
-
-    /// The top of a multi-line label.
-    fn label_multi_bottom_line(
-        &mut self,
-        severity: Severity,
-        label_style: LabelStyle,
-        len: usize,
-    ) -> io::Result<()> {
-        self.set_color(self.styles().label(severity, label_style))?;
-        for _ in 0..len {
-            write!(self, "{}", self.config.chars.multi_bottom)?;
-        }
-        self.reset()?;
-        Ok(())
-    }
-
     /// The top-left of a multi-line label.
     ///
     /// ```text
@@ -588,10 +828,21 @@
         range: RangeTo<usize>,
     ) -> io::Result<()> {
         self.set_color(self.styles().label(severity, label_style))?;
-        for _ in 0..(self.config.width(&source[range.clone()]) + 1) {
-            write!(self, "{}", self.chars().multi_top)?;
+
+        for (metrics, _) in self
+            .char_metrics(source.char_indices())
+            .take_while(|(metrics, _)| metrics.byte_index < range.end + 1)
+        {
+            // FIXME: improve rendering of carets between character boundaries
+            (0..metrics.unicode_width)
+                .try_for_each(|_| write!(self, "{}", self.chars().multi_top))?;
         }
-        write!(self, "{}", self.chars().multi_caret_char_start(label_style))?;
+
+        let caret_start = match label_style {
+            LabelStyle::Primary => self.config.chars.multi_primary_caret_start,
+            LabelStyle::Secondary => self.config.chars.multi_secondary_caret_start,
+        };
+        write!(self, "{}", caret_start)?;
         self.reset()?;
         write!(self, "\n")?;
         Ok(())
@@ -611,10 +862,21 @@
         message: &str,
     ) -> io::Result<()> {
         self.set_color(self.styles().label(severity, label_style))?;
-        for _ in 0..self.config.width(&source[range.clone()]) {
-            write!(self, "{}", self.chars().multi_bottom)?;
+
+        for (metrics, _) in self
+            .char_metrics(source.char_indices())
+            .take_while(|(metrics, _)| metrics.byte_index < range.end)
+        {
+            // FIXME: improve rendering of carets between character boundaries
+            (0..metrics.unicode_width)
+                .try_for_each(|_| write!(self, "{}", self.chars().multi_bottom))?;
         }
-        write!(self, "{}", self.chars().multi_caret_char_end(label_style))?;
+
+        let caret_end = match label_style {
+            LabelStyle::Primary => self.config.chars.multi_primary_caret_start,
+            LabelStyle::Secondary => self.config.chars.multi_secondary_caret_start,
+        };
+        write!(self, "{}", caret_end)?;
         if !message.is_empty() {
             write!(self, " {}", message)?;
         }
@@ -631,8 +893,16 @@
     ) -> io::Result<()> {
         match underline {
             None => self.inner_gutter_space(),
-            Some((ls, VerticalBound::Top)) => self.label_multi_top_line(severity, ls, 2),
-            Some((ls, VerticalBound::Bottom)) => self.label_multi_bottom_line(severity, ls, 2),
+            Some((label_style, vertical_bound)) => {
+                self.set_color(self.styles().label(severity, label_style))?;
+                let ch = match vertical_bound {
+                    VerticalBound::Top => self.config.chars.multi_top,
+                    VerticalBound::Bottom => self.config.chars.multi_bottom,
+                };
+                write!(self, "{0}{0}", ch)?;
+                self.reset()?;
+                Ok(())
+            }
         }
     }
 
@@ -646,16 +916,14 @@
         &mut self,
         severity: Severity,
         num_multi_labels: usize,
-        multi_labels: &[(usize, MultiLabel<'_>)],
+        multi_labels: &[(usize, LabelStyle, MultiLabel<'_>)],
     ) -> io::Result<()> {
         let mut multi_labels_iter = multi_labels.iter().peekable();
         for label_column in 0..num_multi_labels {
             match multi_labels_iter.peek() {
-                Some((label_index, label)) if *label_index == label_column => match label {
-                    MultiLabel::TopLeft(label_style)
-                    | MultiLabel::Left(label_style)
-                    | MultiLabel::Bottom(label_style, ..) => {
-                        self.label_multi_left(severity, *label_style, None)?;
+                Some((label_index, ls, label)) if *label_index == label_column => match label {
+                    MultiLabel::TopLeft | MultiLabel::Left | MultiLabel::Bottom(..) => {
+                        self.label_multi_left(severity, *ls, None)?;
                         multi_labels_iter.next();
                     }
                     MultiLabel::Top(..) => {
@@ -663,7 +931,7 @@
                         multi_labels_iter.next();
                     }
                 },
-                Some((_, _)) | None => self.inner_gutter_space()?,
+                Some((_, _, _)) | None => self.inner_gutter_space()?,
             }
         }
 
@@ -699,83 +967,36 @@
     }
 }
 
-/// Searches for character boundary from byte_index towards the end of the string.
-fn closest_char_boundary(s: &str, byte_index: usize) -> usize {
-    let length = s.len();
-    for index in byte_index..=length {
-        if s.is_char_boundary(index) {
-            return index;
-        }
-    }
-    length
+struct Metrics {
+    byte_index: usize,
+    unicode_width: usize,
 }
 
-/// Searches for character boundary from byte_index towards the start of the string.
-fn closest_char_boundary_rev(s: &str, byte_index: usize) -> usize {
-    for index in (0..=byte_index).rev() {
-        if s.is_char_boundary(index) {
-            return index;
-        }
-    }
-    0
+/// Check if two ranges overlap
+fn is_overlapping(range0: &Range<usize>, range1: &Range<usize>) -> bool {
+    let start = std::cmp::max(range0.start, range1.start);
+    let end = std::cmp::min(range0.end, range1.end);
+    start < end
 }
 
-/// Finds a valid unicode boundaries looking from `range.start` towards the beginning of the string.
-/// From `range.end` towards the end of the string. Returning a `&str` of all characters
-/// that overlapping the range.
-fn slice_at_char_boundaries<'a>(s: &'a str, range: Range<usize>) -> &'a str {
-    let start = closest_char_boundary_rev(s, range.start);
-    let end = closest_char_boundary(s, range.end);
-    &s[start..end]
+/// For prioritizing primary labels over secondary labels when rendering carets.
+fn label_priority_key(label_style: &LabelStyle) -> u8 {
+    match label_style {
+        LabelStyle::Secondary => 0,
+        LabelStyle::Primary => 1,
+    }
 }
 
-#[cfg(test)]
-mod test {
-    use super::*;
-    use std::iter::repeat;
-
-    #[test]
-    fn test_boundary() {
-        let s = "🌞";
-        assert_eq!(closest_char_boundary(s, 0), 0);
-        assert_eq!(closest_char_boundary_rev(s, 0), 0);
-        for i in 1..s.len() {
-            assert_eq!(closest_char_boundary_rev(s, i), 0);
-            assert_eq!(closest_char_boundary(s, i), s.len());
-        }
-    }
-
-    #[test]
-    fn test_boundaries() {
-        let s = "🌑🌒🌓🌔";
-        let individually = ["🌑", "🌒", "🌓", "🌔"];
-
-        let mut expect = Vec::new();
-        // [(0, 0, "", ""),
-        //  (0, 4, "🌑", "🌑"), repeated 4 times,
-        //  (4, 4, "", ""), once
-        //  (4, 8, "🌒", "🌒"), repeated 4 times, and so on (+4, +4)
-        //  ...
-        //  (16, 16, "", ""); 21]
-        expect.push((0, 0, "", ""));
-        for (idx, &char) in individually.iter().enumerate() {
-            let n = char.len();
-            assert_eq!(n, 4);
-            let expected_start = (idx % n) * n;
-            let expected_end = (idx % n) * n + n;
-            expect.extend(repeat((expected_start, expected_end, char, char)).take(n - 1));
-            expect.push((expected_end, expected_end, "", ""));
-        }
-
-        // drop mut.
-        let expect = expect;
-        let mut found = Vec::new();
-        for i in 0..=s.len() {
-            let sliced = slice_at_char_boundaries(s, i..i);
-            let prev = closest_char_boundary_rev(s, i);
-            let next = closest_char_boundary(s, i);
-            found.push((prev, next, &s[prev..next], sliced));
-        }
-        assert_eq!(found, expect);
-    }
+/// Return an iterator that yields the labels that require hanging messages
+/// rendered underneath them.
+fn hanging_labels<'labels, 'diagnostic>(
+    single_labels: &'labels [SingleLabel<'diagnostic>],
+    trailing_label: Option<(usize, &'labels SingleLabel<'diagnostic>)>,
+) -> impl 'labels + DoubleEndedIterator<Item = &'labels SingleLabel<'diagnostic>> {
+    single_labels
+        .iter()
+        .enumerate()
+        .filter(|(_, (_, _, message))| !message.is_empty())
+        .filter(move |(i, _)| trailing_label.map_or(true, |(j, _)| *i != j))
+        .map(|(_, label)| label)
 }
diff --git a/src/term/views.rs b/src/term/views.rs
index e6f6cc1..aa79914 100644
--- a/src/term/views.rs
+++ b/src/term/views.rs
@@ -68,7 +68,7 @@
             range: std::ops::Range<usize>,
             // TODO: How do we reuse these allocations?
             single_labels: Vec<SingleLabel<'diagnostic>>,
-            multi_labels: Vec<(usize, MultiLabel<'diagnostic>)>,
+            multi_labels: Vec<(usize, LabelStyle, MultiLabel<'diagnostic>)>,
         }
 
         // TODO: Make this data structure external, to allow for allocation reuse
@@ -143,14 +143,21 @@
                     // to piggyback off its lexicographic comparison implementation.
                     (range.start, range.end).cmp(&(label_start, label_end))
                 }) {
-                    // If the ranges are the same, order the labels as they
-                    // originally were specified in the diagnostic.
-                    Ok(index) => index + 1,
-                    Err(index) => index,
+                    // If the ranges are the same, order the labels in reverse
+                    // to how they were originally specified in the diagnostic.
+                    // This helps with printing in the renderer.
+                    Ok(index) | Err(index) => index,
                 };
 
+                // Ensure that we print at least one caret, even when we
+                // have a zero-length source range.
+                let mut label_range = label_start..label_end;
+                if label_range.len() == 0 {
+                    label_range.end = label_range.start + 1;
+                }
+
                 line.single_labels
-                    .insert(index, (label.style, label_start..label_end, &label.message));
+                    .insert(index, (label.style, label_range, &label.message));
             } else {
                 // Multiple lines
                 //
@@ -182,7 +189,7 @@
                         // ```text
                         // 4 │ ╭     case (mod num 5) (mod num 3) of
                         // ```
-                        "" => (label_index, MultiLabel::TopLeft(label.style)),
+                        "" => (label_index, label.style, MultiLabel::TopLeft),
                         // There's source code in the prefix, so run a label
                         // underneath it to get to the start of the range.
                         //
@@ -190,7 +197,7 @@
                         // 4 │   fizz₁ num = case (mod num 5) (mod num 3) of
                         //   │ ╭─────────────^
                         // ```
-                        _ => (label_index, MultiLabel::Top(label.style, ..label_start)),
+                        _ => (label_index, label.style, MultiLabel::Top(..label_start)),
                     });
 
                 // Marked lines
@@ -210,7 +217,7 @@
                     labeled_file
                         .get_or_insert_line(line_index, line_range, line_number)
                         .multi_labels
-                        .push((label_index, MultiLabel::Left(label.style)));
+                        .push((label_index, label.style, MultiLabel::Left));
                 }
 
                 // Last labeled line
@@ -226,13 +233,12 @@
                     .multi_labels
                     .push((
                         label_index,
-                        MultiLabel::Bottom(label.style, ..label_end, &label.message),
+                        label.style,
+                        MultiLabel::Bottom(..label_end, &label.message),
                     ));
             }
         }
 
-        // TODO: Insert `None` spaces in `labeled_files`
-
         // Header and message
         //
         // ```text
@@ -254,7 +260,8 @@
         //   │         ^^ expected `Int` but found `String`
         //   │
         // ```
-        for labeled_file in labeled_files {
+        let mut labeled_files = labeled_files.into_iter().peekable();
+        while let Some(labeled_file) = labeled_files.next() {
             let source = files.source(labeled_file.file_id).unwrap();
             let source = source.as_ref();
 
@@ -330,12 +337,22 @@
                     }
                 }
             }
-            renderer.render_snippet_empty(
-                outer_padding,
-                self.diagnostic.severity,
-                labeled_file.num_multi_labels,
-                &current_labels,
-            )?;
+
+            // Check to see if we should render a trailing border after the
+            // final line of the snippet.
+            if labeled_files.peek().is_none() && self.diagnostic.notes.is_empty() {
+                // We don't render a border if we are at the final newline
+                // without trailing notes, because it would end up looking too
+                // spaced-out in combination with the final new line.
+            } else {
+                // Render the trailing snippet border.
+                renderer.render_snippet_empty(
+                    outer_padding,
+                    self.diagnostic.severity,
+                    labeled_file.num_multi_labels,
+                    &current_labels,
+                )?;
+            }
         }
 
         // Additional notes
diff --git a/tests/snapshots/term__empty_ranges__rich_color.snap b/tests/snapshots/term__empty_ranges__rich_color.snap
index d1e9a2e..89bb2c0 100644
--- a/tests/snapshots/term__empty_ranges__rich_color.snap
+++ b/tests/snapshots/term__empty_ranges__rich_color.snap
@@ -5,22 +5,25 @@
 {fg:Green bold bright}note{bold bright}: middle{/}
   {fg:Blue}┌─{/} hello:1:7
   {fg:Blue}│{/}
-{fg:Blue}1{/} {fg:Blue}│{/} Hello world!
-  {fg:Blue}│{/}       {fg:Green}^ middle{/}
-  {fg:Blue}│{/}
+{fg:Blue}1{/} {fg:Blue}│{/} Hello {fg:Green}w{/}orld!
+  {fg:Blue}│{/}       {fg:Green}^{/} {fg:Green}middle{/}
 
 {fg:Green bold bright}note{bold bright}: end of line{/}
   {fg:Blue}┌─{/} hello:1:13
   {fg:Blue}│{/}
 {fg:Blue}1{/} {fg:Blue}│{/} Hello world!
-  {fg:Blue}│{/}             {fg:Green}^ end of line{/}
-  {fg:Blue}│{/}
+  {fg:Blue}│{/}             {fg:Green}^{/} {fg:Green}end of line{/}
 
-{fg:Green bold bright}note{bold bright}: end of file{/}
+{fg:Green bold bright}note{bold bright}: end of line{/}
   {fg:Blue}┌─{/} hello:2:11
   {fg:Blue}│{/}
 {fg:Blue}2{/} {fg:Blue}│{/} Bye world!
-  {fg:Blue}│{/}           {fg:Green}^ end of file{/}
+  {fg:Blue}│{/}           {fg:Green}^{/} {fg:Green}end of line{/}
+
+{fg:Green bold bright}note{bold bright}: end of file{/}
+  {fg:Blue}┌─{/} hello:3:4
   {fg:Blue}│{/}
+{fg:Blue}3{/} {fg:Blue}│{/}    
+  {fg:Blue}│{/}    {fg:Green}^{/} {fg:Green}end of file{/}
 
 
diff --git a/tests/snapshots/term__empty_ranges__rich_no_color.snap b/tests/snapshots/term__empty_ranges__rich_no_color.snap
index fa28550..862605c 100644
--- a/tests/snapshots/term__empty_ranges__rich_no_color.snap
+++ b/tests/snapshots/term__empty_ranges__rich_no_color.snap
@@ -7,20 +7,23 @@
   │
 1 │ Hello world!
   │       ^ middle
-  │
 
 note: end of line
   ┌─ hello:1:13
   │
 1 │ Hello world!
   │             ^ end of line
-  │
 
-note: end of file
+note: end of line
   ┌─ hello:2:11
   │
 2 │ Bye world!
-  │           ^ end of file
+  │           ^ end of line
+
+note: end of file
+  ┌─ hello:3:4
   │
+3 │    
+  │    ^ end of file
 
 
diff --git a/tests/snapshots/term__empty_ranges__short_color.snap b/tests/snapshots/term__empty_ranges__short_color.snap
index b3930e0..3713ee4 100644
--- a/tests/snapshots/term__empty_ranges__short_color.snap
+++ b/tests/snapshots/term__empty_ranges__short_color.snap
@@ -4,5 +4,6 @@
 ---
 hello:1:7: {fg:Green bold bright}note{bold bright}: middle{/}
 hello:1:13: {fg:Green bold bright}note{bold bright}: end of line{/}
-hello:2:11: {fg:Green bold bright}note{bold bright}: end of file{/}
+hello:2:11: {fg:Green bold bright}note{bold bright}: end of line{/}
+hello:3:4: {fg:Green bold bright}note{bold bright}: end of file{/}
 
diff --git a/tests/snapshots/term__empty_ranges__short_no_color.snap b/tests/snapshots/term__empty_ranges__short_no_color.snap
index 5e2edfc..635a830 100644
--- a/tests/snapshots/term__empty_ranges__short_no_color.snap
+++ b/tests/snapshots/term__empty_ranges__short_no_color.snap
@@ -4,5 +4,6 @@
 ---
 hello:1:7: note: middle
 hello:1:13: note: end of line
-hello:2:11: note: end of file
+hello:2:11: note: end of line
+hello:3:4: note: end of file
 
diff --git a/tests/snapshots/term__fizz_buzz__rich_color.snap b/tests/snapshots/term__fizz_buzz__rich_color.snap
index 63bfdb9..a051eef 100644
--- a/tests/snapshots/term__fizz_buzz__rich_color.snap
+++ b/tests/snapshots/term__fizz_buzz__rich_color.snap
@@ -6,14 +6,14 @@
   {fg:Blue}┌─{/} FizzBuzz.fun:3:15
   {fg:Blue}│{/}  
 {fg:Blue}3{/} {fg:Blue}│{/}   fizz₁ : Nat → String
-  {fg:Blue}│{/}                 {fg:Blue}------ expected type `String` found here{/}
+  {fg:Blue}│{/}                 {fg:Blue}------{/} {fg:Blue}expected type `String` found here{/}
 {fg:Blue}4{/} {fg:Blue}│{/}   fizz₁ num = case (mod num 5) (mod num 3) of
   {fg:Blue}│{/} {fg:Blue}╭{/}{fg:Blue}─────────────'{/}
 {fg:Blue}5{/} {fg:Blue}│{/} {fg:Blue}│{/}     0 0 => "FizzBuzz"
 {fg:Blue}6{/} {fg:Blue}│{/} {fg:Blue}│{/}     0 _ => "Fizz"
 {fg:Blue}7{/} {fg:Blue}│{/} {fg:Blue}│{/}     _ 0 => "Buzz"
-{fg:Blue}8{/} {fg:Blue}│{/} {fg:Blue}│{/}     _ _ => num
-  {fg:Blue}│{/} {fg:Blue}│{/}            {fg:Red}^^^ expected `String`, found `Nat`{/}
+{fg:Blue}8{/} {fg:Blue}│{/} {fg:Blue}│{/}     _ _ => {fg:Red}num{/}
+  {fg:Blue}│{/} {fg:Blue}│{/}            {fg:Red}^^^{/} {fg:Red}expected `String`, found `Nat`{/}
   {fg:Blue}│{/} {fg:Blue}╰{/}{fg:Blue}──────────────' `case` clauses have incompatible types{/}
   {fg:Blue}│{/}  
   {fg:Blue}={/} expected type `String`
@@ -23,17 +23,17 @@
    {fg:Blue}┌─{/} FizzBuzz.fun:10:15
    {fg:Blue}│{/}  
 {fg:Blue}10{/} {fg:Blue}│{/}   fizz₂ : Nat → String
-   {fg:Blue}│{/}                 {fg:Blue}------ expected type `String` found here{/}
+   {fg:Blue}│{/}                 {fg:Blue}------{/} {fg:Blue}expected type `String` found here{/}
 {fg:Blue}11{/} {fg:Blue}│{/}   fizz₂ num =
 {fg:Blue}12{/} {fg:Blue}│{/} {fg:Blue}╭{/}     case (mod num 5) (mod num 3) of
 {fg:Blue}13{/} {fg:Blue}│{/} {fg:Blue}│{/}         0 0 => "FizzBuzz"
-   {fg:Blue}│{/} {fg:Blue}│{/}                {fg:Blue}---------- this is found to be of type `String`{/}
+   {fg:Blue}│{/} {fg:Blue}│{/}                {fg:Blue}----------{/} {fg:Blue}this is found to be of type `String`{/}
 {fg:Blue}14{/} {fg:Blue}│{/} {fg:Blue}│{/}         0 _ => "Fizz"
-   {fg:Blue}│{/} {fg:Blue}│{/}                {fg:Blue}------ this is found to be of type `String`{/}
+   {fg:Blue}│{/} {fg:Blue}│{/}                {fg:Blue}------{/} {fg:Blue}this is found to be of type `String`{/}
 {fg:Blue}15{/} {fg:Blue}│{/} {fg:Blue}│{/}         _ 0 => "Buzz"
-   {fg:Blue}│{/} {fg:Blue}│{/}                {fg:Blue}------ this is found to be of type `String`{/}
-{fg:Blue}16{/} {fg:Blue}│{/} {fg:Blue}│{/}         _ _ => num
-   {fg:Blue}│{/} {fg:Blue}│{/}                {fg:Red}^^^ expected `String`, found `Nat`{/}
+   {fg:Blue}│{/} {fg:Blue}│{/}                {fg:Blue}------{/} {fg:Blue}this is found to be of type `String`{/}
+{fg:Blue}16{/} {fg:Blue}│{/} {fg:Blue}│{/}         _ _ => {fg:Red}num{/}
+   {fg:Blue}│{/} {fg:Blue}│{/}                {fg:Red}^^^{/} {fg:Red}expected `String`, found `Nat`{/}
    {fg:Blue}│{/} {fg:Blue}╰{/}{fg:Blue}──────────────────' `case` clauses have incompatible types{/}
    {fg:Blue}│{/}  
    {fg:Blue}={/} expected type `String`
diff --git a/tests/snapshots/term__multifile__rich_color.snap b/tests/snapshots/term__multifile__rich_color.snap
index 5c3be31..514be49 100644
--- a/tests/snapshots/term__multifile__rich_color.snap
+++ b/tests/snapshots/term__multifile__rich_color.snap
@@ -5,29 +5,29 @@
 {fg:Red bold bright}error{bold bright}: unknown builtin: `NATRAL`{/}
   {fg:Blue}┌─{/} Data/Nat.fun:7:13
   {fg:Blue}│{/}
-{fg:Blue}7{/} {fg:Blue}│{/} {-# BUILTIN NATRAL Nat #-}
-  {fg:Blue}│{/}             {fg:Red}^^^^^^ unknown builtin{/}
+{fg:Blue}7{/} {fg:Blue}│{/} {-# BUILTIN {fg:Red}NATRAL{/} Nat #-}
+  {fg:Blue}│{/}             {fg:Red}^^^^^^{/} {fg:Red}unknown builtin{/}
   {fg:Blue}│{/}
   {fg:Blue}={/} there is a builtin with a similar name: `NATURAL`
 
 {fg:Yellow bold bright}warning{bold bright}: unused parameter pattern: `n₂`{/}
    {fg:Blue}┌─{/} Data/Nat.fun:17:16
    {fg:Blue}│{/}
-{fg:Blue}17{/} {fg:Blue}│{/} zero    - succ n₂ = zero
-   {fg:Blue}│{/}                {fg:Yellow}^^ unused parameter{/}
+{fg:Blue}17{/} {fg:Blue}│{/} zero    - succ {fg:Yellow}n₂{/} = zero
+   {fg:Blue}│{/}                {fg:Yellow}^^{/} {fg:Yellow}unused parameter{/}
    {fg:Blue}│{/}
    {fg:Blue}={/} consider using a wildcard pattern: `_`
 
 {fg:Red bold bright}error[E0001]{bold bright}: unexpected type in application of `_+_`{/}
    {fg:Blue}┌─{/} Test.fun:4:11
    {fg:Blue}│{/}
-{fg:Blue} 4{/} {fg:Blue}│{/} _ = 123 + "hello"
-   {fg:Blue}│{/}           {fg:Red}^^^^^^^ expected `Nat`, found `String`{/}
+{fg:Blue} 4{/} {fg:Blue}│{/} _ = 123 + {fg:Red}"hello"{/}
+   {fg:Blue}│{/}           {fg:Red}^^^^^^^{/} {fg:Red}expected `Nat`, found `String`{/}
    {fg:Blue}│{/}
    {fg:Blue}┌─{/} Data/Nat.fun:11:1
    {fg:Blue}│{/}
 {fg:Blue}11{/} {fg:Blue}│{/} _+_ : Nat → Nat → Nat
-   {fg:Blue}│{/} {fg:Blue}--------------------- based on the definition of `_+_`{/}
+   {fg:Blue}│{/} {fg:Blue}---------------------{/} {fg:Blue}based on the definition of `_+_`{/}
    {fg:Blue}│{/}
    {fg:Blue}={/} expected type `Nat`
         found type `String`
diff --git a/tests/snapshots/term__multiline_overlapping__rich_color.snap b/tests/snapshots/term__multiline_overlapping__rich_color.snap
index 87f8bed..fee20e1 100644
--- a/tests/snapshots/term__multiline_overlapping__rich_color.snap
+++ b/tests/snapshots/term__multiline_overlapping__rich_color.snap
@@ -7,14 +7,14 @@
   {fg:Blue}│{/}    
 {fg:Blue}1{/} {fg:Blue}│{/}   {fg:Blue}╭{/}         match line_index.compare(self.last_line_index()) {
 {fg:Blue}2{/} {fg:Blue}│{/}   {fg:Blue}│{/}             Ordering::Less => Ok(self.line_starts()[line_index.to_usize()]),
-  {fg:Blue}│{/}   {fg:Blue}│{/}                               {fg:Blue}--------------------------------------------- this is found to be of type `Result<ByteIndex, LineIndexOutOfBoundsError>`{/}
+  {fg:Blue}│{/}   {fg:Blue}│{/}                               {fg:Blue}---------------------------------------------{/} {fg:Blue}this is found to be of type `Result<ByteIndex, LineIndexOutOfBoundsError>`{/}
 {fg:Blue}3{/} {fg:Blue}│{/}   {fg:Blue}│{/}             Ordering::Equal => Ok(self.source_span().end()),
-  {fg:Blue}│{/}   {fg:Blue}│{/}                                {fg:Blue}---------------------------- this is found to be of type `Result<ByteIndex, LineIndexOutOfBoundsError>`{/}
-{fg:Blue}4{/} {fg:Blue}│{/}   {fg:Blue}│{/}             Ordering::Greater => LineIndexOutOfBoundsError {
+  {fg:Blue}│{/}   {fg:Blue}│{/}                                {fg:Blue}----------------------------{/} {fg:Blue}this is found to be of type `Result<ByteIndex, LineIndexOutOfBoundsError>`{/}
+{fg:Blue}4{/} {fg:Blue}│{/}   {fg:Blue}│{/}             Ordering::Greater => {fg:Red}LineIndexOutOfBoundsError {{/}
   {fg:Blue}│{/} {fg:Red}╭{/}{fg:Red}─{/}{fg:Blue}│{/}{fg:Red}──────────────────────────────────^{/}
-{fg:Blue}5{/} {fg:Blue}│{/} {fg:Red}│{/} {fg:Blue}│{/}                 given: line_index,
-{fg:Blue}6{/} {fg:Blue}│{/} {fg:Red}│{/} {fg:Blue}│{/}                 max: self.last_line_index(),
-{fg:Blue}7{/} {fg:Blue}│{/} {fg:Red}│{/} {fg:Blue}│{/}             },
+{fg:Blue}5{/} {fg:Blue}│{/} {fg:Red}│{/} {fg:Blue}│{/} {fg:Red}                given: line_index,{/}
+{fg:Blue}6{/} {fg:Blue}│{/} {fg:Red}│{/} {fg:Blue}│{/} {fg:Red}                max: self.last_line_index(),{/}
+{fg:Blue}7{/} {fg:Blue}│{/} {fg:Red}│{/} {fg:Blue}│{/} {fg:Red}            }{/},
   {fg:Blue}│{/} {fg:Red}╰{/}{fg:Red}─{/}{fg:Blue}│{/}{fg:Red}─────────────^ expected enum `Result`, found struct `LineIndexOutOfBoundsError`{/}
 {fg:Blue}8{/} {fg:Blue}│{/}   {fg:Blue}│{/}         }
   {fg:Blue}│{/}   {fg:Blue}╰{/}{fg:Blue}─────────' `match` arms have incompatible types{/}
diff --git a/tests/snapshots/term__one_line__rich_color.snap b/tests/snapshots/term__one_line__rich_color.snap
deleted file mode 100644
index 6f0a7f4..0000000
--- a/tests/snapshots/term__one_line__rich_color.snap
+++ /dev/null
@@ -1,17 +0,0 @@
----
-source: codespan-reporting/tests/term.rs
-expression: TEST_DATA.emit_color(&config)
----
-{fg:Red bold bright}error[E0499]{bold bright}: cannot borrow `v` as mutable more than once at a time{/}
-  {fg:Blue}┌─{/} one_line.rs:3:5
-  {fg:Blue}│{/}
-{fg:Blue}3{/} {fg:Blue}│{/}     v.push(v.pop().unwrap());
-  {fg:Blue}│{/}     {fg:Blue}- first borrow later used by call{/}
-  {fg:Blue}│{/}       {fg:Blue}---- first mutable borrow occurs here{/}
-  {fg:Blue}│{/}            {fg:Red}^ second mutable borrow occurs here{/}
-  {fg:Blue}│{/}
-
-{fg:Red bold bright}error{bold bright}: aborting due to previous error{/}
- {fg:Blue}={/} For more information about this error, try `rustc --explain E0499`.
-
-
diff --git a/tests/snapshots/term__overlapping__rich_color.snap b/tests/snapshots/term__overlapping__rich_color.snap
new file mode 100644
index 0000000..92f061f
--- /dev/null
+++ b/tests/snapshots/term__overlapping__rich_color.snap
@@ -0,0 +1,58 @@
+---
+source: codespan-reporting/tests/term.rs
+expression: TEST_DATA.emit_color(&config)
+---
+{fg:Red bold bright}error[E0666]{bold bright}: nested `impl Trait` is not allowed{/}
+  {fg:Blue}┌─{/} nested_impl_trait.rs:5:46
+  {fg:Blue}│{/}
+{fg:Blue}5{/} {fg:Blue}│{/} fn bad_in_ret_position(x: impl Into<u32>) -> impl Into<{fg:Red}impl Debug{/}> { x }
+  {fg:Blue}│{/}                                              {fg:Blue}----------{fg:Red}^^^^^^^^^^{fg:Blue}-{/}
+  {fg:Blue}│{/}                                              {fg:Blue}│{/}         {fg:Red}│{/}
+  {fg:Blue}│{/}                                              {fg:Blue}│{/}         {fg:Red}nested `impl Trait` here{/}
+  {fg:Blue}│{/}                                              {fg:Blue}outer `impl Trait`{/}
+
+{fg:Red bold bright}error[E0121]{bold bright}: the type placeholder `_` is not allowed within types on item signatures{/}
+  {fg:Blue}┌─{/} typeck_type_placeholder_item.rs:1:18
+  {fg:Blue}│{/}
+{fg:Blue}1{/} {fg:Blue}│{/} fn fn_test1() -> {fg:Red}_{/} { 5 }
+  {fg:Blue}│{/}                  {fg:Red}^{/}
+  {fg:Blue}│{/}                  {fg:Red}│{/}
+  {fg:Blue}│{/}                  {fg:Red}not allowed in type signatures{/}
+  {fg:Blue}│{/}                  {fg:Blue}help: replace with the correct return type: `i32`{/}
+
+{fg:Red bold bright}error[E0121]{bold bright}: the type placeholder `_` is not allowed within types on item signatures{/}
+  {fg:Blue}┌─{/} typeck_type_placeholder_item.rs:2:24
+  {fg:Blue}│{/}
+{fg:Blue}2{/} {fg:Blue}│{/} fn fn_test2(x: i32) -> ({fg:Red}_{/}, {fg:Red}_{/}) { (x, x) }
+  {fg:Blue}│{/}                        {fg:Blue}-{fg:Red}^{fg:Blue}--{fg:Red}^{fg:Blue}-{/}
+  {fg:Blue}│{/}                        {fg:Blue}│{/}{fg:Red}│{/}  {fg:Red}│{/}
+  {fg:Blue}│{/}                        {fg:Blue}│{/}{fg:Red}│{/}  {fg:Red}not allowed in type signatures{/}
+  {fg:Blue}│{/}                        {fg:Blue}│{/}{fg:Red}not allowed in type signatures{/}
+  {fg:Blue}│{/}                        {fg:Blue}help: replace with the correct return type: `(i32, i32)`{/}
+
+{fg:Red bold bright}error[E0277]{bold bright}: `std::rc::Rc<()>` cannot be sent between threads safely{/}
+   {fg:Blue}┌─{/} no_send_res_ports.rs:25:5
+   {fg:Blue}│{/}  
+{fg:Blue}25{/} {fg:Blue}│{/}       {fg:Red}thread::spawn{/}(move|| {
+   {fg:Blue}│{/}       {fg:Red}^^^^^^^^^^^^^{/} {fg:Red}`std::rc::Rc<()>` cannot be sent between threads safely{/}
+   {fg:Blue}│{/} {fg:Blue}╭{/}{fg:Blue}───────────────────'{/}
+{fg:Blue}26{/} {fg:Blue}│{/} {fg:Blue}│{/}         let y = x;
+{fg:Blue}27{/} {fg:Blue}│{/} {fg:Blue}│{/}         println!("{:?}", y);
+{fg:Blue}28{/} {fg:Blue}│{/} {fg:Blue}│{/}     });
+   {fg:Blue}│{/} {fg:Blue}╰{/}{fg:Blue}──────' within this `[closure@no_send_res_ports.rs:29:19: 33:6 x:main::Foo]`{/}
+   {fg:Blue}│{/}  
+   {fg:Blue}┌─{/} libstd/thread/mod.rs:5:8
+   {fg:Blue}│{/}
+{fg:Blue} 5{/} {fg:Blue}│{/}     F: Send + 'static,
+   {fg:Blue}│{/}        {fg:Blue}----{/} {fg:Blue}required by this bound in `std::thread::spawn`{/}
+   {fg:Blue}│{/}
+   {fg:Blue}={/} help: within `[closure@no_send_res_ports.rs:29:19: 33:6 x:main::Foo]`, the trait `std::marker::Send` is not implemented for `std::rc::Rc<()>`
+   {fg:Blue}={/} note: required because it appears within the type `Port<()>`
+   {fg:Blue}={/} note: required because it appears within the type `main::Foo`
+   {fg:Blue}={/} note: required because it appears within the type `[closure@no_send_res_ports.rs:29:19: 33:6 x:main::Foo]`
+
+{fg:Red bold bright}error{bold bright}: aborting due 5 previous errors{/}
+ {fg:Blue}={/} Some errors have detailed explanations: E0121, E0277, E0666.
+ {fg:Blue}={/} For more information about an error, try `rustc --explain E0121`.
+
+
diff --git a/tests/snapshots/term__overlapping__rich_no_color.snap b/tests/snapshots/term__overlapping__rich_no_color.snap
new file mode 100644
index 0000000..e4a944d
--- /dev/null
+++ b/tests/snapshots/term__overlapping__rich_no_color.snap
@@ -0,0 +1,58 @@
+---
+source: codespan-reporting/tests/term.rs
+expression: TEST_DATA.emit_no_color(&config)
+---
+error[E0666]: nested `impl Trait` is not allowed
+  ┌─ nested_impl_trait.rs:5:46
+  │
+5 │ fn bad_in_ret_position(x: impl Into<u32>) -> impl Into<impl Debug> { x }
+  │                                              ----------^^^^^^^^^^-
+  │                                              │         │
+  │                                              │         nested `impl Trait` here
+  │                                              outer `impl Trait`
+
+error[E0121]: the type placeholder `_` is not allowed within types on item signatures
+  ┌─ typeck_type_placeholder_item.rs:1:18
+  │
+1 │ fn fn_test1() -> _ { 5 }
+  │                  ^
+  │                  │
+  │                  not allowed in type signatures
+  │                  help: replace with the correct return type: `i32`
+
+error[E0121]: the type placeholder `_` is not allowed within types on item signatures
+  ┌─ typeck_type_placeholder_item.rs:2:24
+  │
+2 │ fn fn_test2(x: i32) -> (_, _) { (x, x) }
+  │                        -^--^-
+  │                        ││  │
+  │                        ││  not allowed in type signatures
+  │                        │not allowed in type signatures
+  │                        help: replace with the correct return type: `(i32, i32)`
+
+error[E0277]: `std::rc::Rc<()>` cannot be sent between threads safely
+   ┌─ no_send_res_ports.rs:25:5
+   │  
+25 │       thread::spawn(move|| {
+   │       ^^^^^^^^^^^^^ `std::rc::Rc<()>` cannot be sent between threads safely
+   │ ╭───────────────────'
+26 │ │         let y = x;
+27 │ │         println!("{:?}", y);
+28 │ │     });
+   │ ╰──────' within this `[closure@no_send_res_ports.rs:29:19: 33:6 x:main::Foo]`
+   │  
+   ┌─ libstd/thread/mod.rs:5:8
+   │
+ 5 │     F: Send + 'static,
+   │        ---- required by this bound in `std::thread::spawn`
+   │
+   = help: within `[closure@no_send_res_ports.rs:29:19: 33:6 x:main::Foo]`, the trait `std::marker::Send` is not implemented for `std::rc::Rc<()>`
+   = note: required because it appears within the type `Port<()>`
+   = note: required because it appears within the type `main::Foo`
+   = note: required because it appears within the type `[closure@no_send_res_ports.rs:29:19: 33:6 x:main::Foo]`
+
+error: aborting due 5 previous errors
+ = Some errors have detailed explanations: E0121, E0277, E0666.
+ = For more information about an error, try `rustc --explain E0121`.
+
+
diff --git a/tests/snapshots/term__overlapping__short_color.snap b/tests/snapshots/term__overlapping__short_color.snap
new file mode 100644
index 0000000..8e33cbf
--- /dev/null
+++ b/tests/snapshots/term__overlapping__short_color.snap
@@ -0,0 +1,11 @@
+---
+source: codespan-reporting/tests/term.rs
+expression: TEST_DATA.emit_color(&config)
+---
+nested_impl_trait.rs:5:56: {fg:Red bold bright}error[E0666]{bold bright}: nested `impl Trait` is not allowed{/}
+typeck_type_placeholder_item.rs:1:18: {fg:Red bold bright}error[E0121]{bold bright}: the type placeholder `_` is not allowed within types on item signatures{/}
+typeck_type_placeholder_item.rs:2:25: {fg:Red bold bright}error[E0121]{bold bright}: the type placeholder `_` is not allowed within types on item signatures{/}
+typeck_type_placeholder_item.rs:2:28: {fg:Red bold bright}error[E0121]{bold bright}: the type placeholder `_` is not allowed within types on item signatures{/}
+no_send_res_ports.rs:25:5: {fg:Red bold bright}error[E0277]{bold bright}: `std::rc::Rc<()>` cannot be sent between threads safely{/}
+{fg:Red bold bright}error{bold bright}: aborting due 5 previous errors{/}
+
diff --git a/tests/snapshots/term__overlapping__short_no_color.snap b/tests/snapshots/term__overlapping__short_no_color.snap
new file mode 100644
index 0000000..47ed5db
--- /dev/null
+++ b/tests/snapshots/term__overlapping__short_no_color.snap
@@ -0,0 +1,11 @@
+---
+source: codespan-reporting/tests/term.rs
+expression: TEST_DATA.emit_no_color(&config)
+---
+nested_impl_trait.rs:5:56: error[E0666]: nested `impl Trait` is not allowed
+typeck_type_placeholder_item.rs:1:18: error[E0121]: the type placeholder `_` is not allowed within types on item signatures
+typeck_type_placeholder_item.rs:2:25: error[E0121]: the type placeholder `_` is not allowed within types on item signatures
+typeck_type_placeholder_item.rs:2:28: error[E0121]: the type placeholder `_` is not allowed within types on item signatures
+no_send_res_ports.rs:25:5: error[E0277]: `std::rc::Rc<()>` cannot be sent between threads safely
+error: aborting due 5 previous errors
+
diff --git a/tests/snapshots/term__same_line__rich_color.snap b/tests/snapshots/term__same_line__rich_color.snap
new file mode 100644
index 0000000..59bd616
--- /dev/null
+++ b/tests/snapshots/term__same_line__rich_color.snap
@@ -0,0 +1,17 @@
+---
+source: codespan-reporting/tests/term.rs
+expression: TEST_DATA.emit_color(&config)
+---
+{fg:Red bold bright}error[E0499]{bold bright}: cannot borrow `v` as mutable more than once at a time{/}
+  {fg:Blue}┌─{/} one_line.rs:3:5
+  {fg:Blue}│{/}
+{fg:Blue}3{/} {fg:Blue}│{/}     v.push({fg:Red}v{/}.pop().unwrap());
+  {fg:Blue}│{/}     {fg:Blue}-{/} {fg:Blue}----{/} {fg:Red}^{/} {fg:Red}second mutable borrow occurs here{/}
+  {fg:Blue}│{/}     {fg:Blue}│{/} {fg:Blue}│{/}     
+  {fg:Blue}│{/}     {fg:Blue}│{/} {fg:Blue}first mutable borrow occurs here{/}
+  {fg:Blue}│{/}     {fg:Blue}first borrow later used by call{/}
+
+{fg:Red bold bright}error{bold bright}: aborting due to previous error{/}
+ {fg:Blue}={/} For more information about this error, try `rustc --explain E0499`.
+
+
diff --git a/tests/snapshots/term__one_line__rich_no_color.snap b/tests/snapshots/term__same_line__rich_no_color.snap
similarity index 67%
rename from tests/snapshots/term__one_line__rich_no_color.snap
rename to tests/snapshots/term__same_line__rich_no_color.snap
index f857bf1..7342f3f 100644
--- a/tests/snapshots/term__one_line__rich_no_color.snap
+++ b/tests/snapshots/term__same_line__rich_no_color.snap
@@ -6,10 +6,10 @@
   ┌─ one_line.rs:3:5
   │
 3 │     v.push(v.pop().unwrap());
-  │     - first borrow later used by call
-  │       ---- first mutable borrow occurs here
-  │            ^ second mutable borrow occurs here
-  │
+  │     - ---- ^ second mutable borrow occurs here
+  │     │ │     
+  │     │ first mutable borrow occurs here
+  │     first borrow later used by call
 
 error: aborting due to previous error
  = For more information about this error, try `rustc --explain E0499`.
diff --git a/tests/snapshots/term__one_line__short_color.snap b/tests/snapshots/term__same_line__short_color.snap
similarity index 100%
rename from tests/snapshots/term__one_line__short_color.snap
rename to tests/snapshots/term__same_line__short_color.snap
diff --git a/tests/snapshots/term__one_line__short_no_color.snap b/tests/snapshots/term__same_line__short_no_color.snap
similarity index 100%
rename from tests/snapshots/term__one_line__short_no_color.snap
rename to tests/snapshots/term__same_line__short_no_color.snap
diff --git a/tests/snapshots/term__same_ranges__rich_color.snap b/tests/snapshots/term__same_ranges__rich_color.snap
index 0860add..e6ec885 100644
--- a/tests/snapshots/term__same_ranges__rich_color.snap
+++ b/tests/snapshots/term__same_ranges__rich_color.snap
@@ -5,9 +5,10 @@
 {fg:Red bold bright}error{bold bright}: Unexpected token{/}
   {fg:Blue}┌─{/} same_range:1:5
   {fg:Blue}│{/}
-{fg:Blue}1{/} {fg:Blue}│{/} ::S { }
-  {fg:Blue}│{/}     {fg:Red}^ Unexpected '{'{/}
-  {fg:Blue}│{/}     {fg:Blue}- Expected '('{/}
-  {fg:Blue}│{/}
+{fg:Blue}1{/} {fg:Blue}│{/} ::S {fg:Red}{{/} }
+  {fg:Blue}│{/}     {fg:Red}^{/}
+  {fg:Blue}│{/}     {fg:Red}│{/}
+  {fg:Blue}│{/}     {fg:Red}Unexpected '{'{/}
+  {fg:Blue}│{/}     {fg:Blue}Expected '('{/}
 
 
diff --git a/tests/snapshots/term__same_ranges__rich_no_color.snap b/tests/snapshots/term__same_ranges__rich_no_color.snap
index 462fc89..09510e6 100644
--- a/tests/snapshots/term__same_ranges__rich_no_color.snap
+++ b/tests/snapshots/term__same_ranges__rich_no_color.snap
@@ -6,8 +6,9 @@
   ┌─ same_range:1:5
   │
 1 │ ::S { }
-  │     ^ Unexpected '{'
-  │     - Expected '('
-  │
+  │     ^
+  │     │
+  │     Unexpected '{'
+  │     Expected '('
 
 
diff --git a/tests/snapshots/term__tab_columns__tab_width_2_no_color.snap b/tests/snapshots/term__tab_columns__tab_width_2_no_color.snap
new file mode 100644
index 0000000..0faa8d8
--- /dev/null
+++ b/tests/snapshots/term__tab_columns__tab_width_2_no_color.snap
@@ -0,0 +1,23 @@
+---
+source: codespan-reporting/tests/term.rs
+expression: TEST_DATA.emit_no_color(&config)
+---
+warning: tab test
+  ┌─ tab_columns:1:2
+  │
+1 │   hello
+  │   ^^^^^
+2 │ ∙ hello
+  │   ^^^^^
+3 │ ∙∙  hello
+  │     ^^^^^
+4 │ ∙∙∙ hello
+  │     ^^^^^
+5 │ ∙∙∙∙  hello
+  │       ^^^^^
+6 │ ∙∙∙∙∙ hello
+  │       ^^^^^
+7 │ ∙∙∙∙∙∙  hello
+  │         ^^^^^
+
+
diff --git a/tests/snapshots/term__tab_columns__tab_width_3_no_color.snap b/tests/snapshots/term__tab_columns__tab_width_3_no_color.snap
new file mode 100644
index 0000000..40f20a6
--- /dev/null
+++ b/tests/snapshots/term__tab_columns__tab_width_3_no_color.snap
@@ -0,0 +1,23 @@
+---
+source: codespan-reporting/tests/term.rs
+expression: TEST_DATA.emit_no_color(&config)
+---
+warning: tab test
+  ┌─ tab_columns:1:2
+  │
+1 │    hello
+  │    ^^^^^
+2 │ ∙  hello
+  │    ^^^^^
+3 │ ∙∙ hello
+  │    ^^^^^
+4 │ ∙∙∙   hello
+  │       ^^^^^
+5 │ ∙∙∙∙  hello
+  │       ^^^^^
+6 │ ∙∙∙∙∙ hello
+  │       ^^^^^
+7 │ ∙∙∙∙∙∙   hello
+  │          ^^^^^
+
+
diff --git a/tests/snapshots/term__tab_columns__tab_width_6_no_color.snap b/tests/snapshots/term__tab_columns__tab_width_6_no_color.snap
new file mode 100644
index 0000000..018a402
--- /dev/null
+++ b/tests/snapshots/term__tab_columns__tab_width_6_no_color.snap
@@ -0,0 +1,23 @@
+---
+source: codespan-reporting/tests/term.rs
+expression: TEST_DATA.emit_no_color(&config)
+---
+warning: tab test
+  ┌─ tab_columns:1:2
+  │
+1 │       hello
+  │       ^^^^^
+2 │ ∙     hello
+  │       ^^^^^
+3 │ ∙∙    hello
+  │       ^^^^^
+4 │ ∙∙∙   hello
+  │       ^^^^^
+5 │ ∙∙∙∙  hello
+  │       ^^^^^
+6 │ ∙∙∙∙∙ hello
+  │       ^^^^^
+7 │ ∙∙∙∙∙∙      hello
+  │             ^^^^^
+
+
diff --git a/tests/snapshots/term__tab_columns__tab_width_default_no_color.snap b/tests/snapshots/term__tab_columns__tab_width_default_no_color.snap
new file mode 100644
index 0000000..67cd187
--- /dev/null
+++ b/tests/snapshots/term__tab_columns__tab_width_default_no_color.snap
@@ -0,0 +1,23 @@
+---
+source: codespan-reporting/tests/term.rs
+expression: TEST_DATA.emit_no_color(&config)
+---
+warning: tab test
+  ┌─ tab_columns:1:2
+  │
+1 │     hello
+  │     ^^^^^
+2 │ ∙   hello
+  │     ^^^^^
+3 │ ∙∙  hello
+  │     ^^^^^
+4 │ ∙∙∙ hello
+  │     ^^^^^
+5 │ ∙∙∙∙    hello
+  │         ^^^^^
+6 │ ∙∙∙∙∙   hello
+  │         ^^^^^
+7 │ ∙∙∙∙∙∙  hello
+  │         ^^^^^
+
+
diff --git a/tests/snapshots/term__tabbed__tab_width_3_no_color.snap b/tests/snapshots/term__tabbed__tab_width_3_no_color.snap
index e8d797c..f7328c3 100644
--- a/tests/snapshots/term__tabbed__tab_width_3_no_color.snap
+++ b/tests/snapshots/term__tabbed__tab_width_3_no_color.snap
@@ -7,20 +7,17 @@
   │
 3 │       Weapon: DogJaw
   │               ^^^^^^ the weapon
-  │
 
 warning: unknown condition `attack-cooldown`
   ┌─ tabbed:4:23
   │
-4 │       ReloadingCondition:   attack-cooldown
-  │                             ^^^^^^^^^^^^^^^ the condition
-  │
+4 │       ReloadingCondition:  attack-cooldown
+  │                            ^^^^^^^^^^^^^^^ the condition
 
 warning: unknown field `Foo`
   ┌─ tabbed:5:2
   │
 5 │    Foo: Bar
   │    ^^^ the field
-  │
 
 
diff --git a/tests/snapshots/term__tabbed__tab_width_6_no_color.snap b/tests/snapshots/term__tabbed__tab_width_6_no_color.snap
index 72991cf..bcd1b2b 100644
--- a/tests/snapshots/term__tabbed__tab_width_6_no_color.snap
+++ b/tests/snapshots/term__tabbed__tab_width_6_no_color.snap
@@ -7,20 +7,17 @@
   │
 3 │             Weapon: DogJaw
   │                     ^^^^^^ the weapon
-  │
 
 warning: unknown condition `attack-cooldown`
   ┌─ tabbed:4:23
   │
-4 │             ReloadingCondition:      attack-cooldown
-  │                                      ^^^^^^^^^^^^^^^ the condition
-  │
+4 │             ReloadingCondition:     attack-cooldown
+  │                                     ^^^^^^^^^^^^^^^ the condition
 
 warning: unknown field `Foo`
   ┌─ tabbed:5:2
   │
 5 │       Foo: Bar
   │       ^^^ the field
-  │
 
 
diff --git a/tests/snapshots/term__tabbed__tab_width_default_no_color.snap b/tests/snapshots/term__tabbed__tab_width_default_no_color.snap
index d3c0ee2..d3a41a0 100644
--- a/tests/snapshots/term__tabbed__tab_width_default_no_color.snap
+++ b/tests/snapshots/term__tabbed__tab_width_default_no_color.snap
@@ -7,20 +7,17 @@
   │
 3 │         Weapon: DogJaw
   │                 ^^^^^^ the weapon
-  │
 
 warning: unknown condition `attack-cooldown`
   ┌─ tabbed:4:23
   │
-4 │         ReloadingCondition:    attack-cooldown
-  │                                ^^^^^^^^^^^^^^^ the condition
-  │
+4 │         ReloadingCondition: attack-cooldown
+  │                             ^^^^^^^^^^^^^^^ the condition
 
 warning: unknown field `Foo`
   ┌─ tabbed:5:2
   │
 5 │     Foo: Bar
   │     ^^^ the field
-  │
 
 
diff --git a/tests/snapshots/term__unicode_spans__rich_no_color.snap b/tests/snapshots/term__unicode_spans__rich_no_color.snap
index e76de4b..653a60e 100644
--- a/tests/snapshots/term__unicode_spans__rich_no_color.snap
+++ b/tests/snapshots/term__unicode_spans__rich_no_color.snap
@@ -6,10 +6,24 @@
   ┌─ moon_jump.rs:1:1
   │
 1 │ 🐄🌑🐄🌒🐄🌓🐄🌔🐄🌕🐄🌖🐄🌗🐄🌘🐄
-  │   ^^ Invalid jump
-  │   -- Cow range does not start at boundary.
-  │   ------ Cow does not start or end at boundary.
-  │     -- Cow range does not end at boundary.
+  │ ^^ Invalid jump
+
+note: invalid unicode range
+  ┌─ moon_jump.rs:1:1
   │
+1 │ 🐄🌑🐄🌒🐄🌓🐄🌔🐄🌕🐄🌖🐄🌗🐄🌘🐄
+  │ -- Cow range does not start at boundary.
+
+note: invalid unicode range
+  ┌─ moon_jump.rs:1:3
+  │
+1 │ 🐄🌑🐄🌒🐄🌓🐄🌔🐄🌕🐄🌖🐄🌗🐄🌘🐄
+  │     -- Cow range does not end at boundary.
+
+note: invalid unicode range
+  ┌─ moon_jump.rs:1:1
+  │
+1 │ 🐄🌑🐄🌒🐄🌓🐄🌔🐄🌕🐄🌖🐄🌗🐄🌘🐄
+  │ ------ Cow does not start or end at boundary.
 
 
diff --git a/tests/snapshots/term__unicode_spans__short_no_color.snap b/tests/snapshots/term__unicode_spans__short_no_color.snap
index 9085082..1b19451 100644
--- a/tests/snapshots/term__unicode_spans__short_no_color.snap
+++ b/tests/snapshots/term__unicode_spans__short_no_color.snap
@@ -3,4 +3,7 @@
 expression: TEST_DATA.emit_no_color(&config)
 ---
 moon_jump.rs:1:1: error[E01]: cow may not jump during new moon.
+note: invalid unicode range
+note: invalid unicode range
+note: invalid unicode range
 
diff --git a/tests/term.rs b/tests/term.rs
index 95cc670..ee02372 100644
--- a/tests/term.rs
+++ b/tests/term.rs
@@ -87,20 +87,23 @@
     test_emit!(short_no_color);
 }
 
-/// Based on: https://github.com/rust-lang/rust/blob/c20d7eecbc0928b57da8fe30b2ef8528e2bdd5be/src/test/ui/codemap_tests/one_line.stderr
-mod one_line {
+/// Based on:
+/// - https://github.com/rust-lang/rust/blob/c20d7eecbc0928b57da8fe30b2ef8528e2bdd5be/src/test/ui/codemap_tests/one_line.stderr
+mod same_line {
     use super::*;
 
     lazy_static::lazy_static! {
-        static ref TEST_DATA: TestData<'static, SimpleFile<&'static str, String>> = {
-            let file = SimpleFile::new(
+        static ref TEST_DATA: TestData<'static, SimpleFiles<&'static str, String>> = {
+            let mut files = SimpleFiles::new();
+
+            let file_id1 = files.add(
                 "one_line.rs",
                 unindent::unindent(r#"
                     fn main() {
                         let mut v = vec![Some("foo"), Some("bar")];
                         v.push(v.pop().unwrap());
                     }
-                "#)
+                "#),
             );
 
             let diagnostics = vec![
@@ -108,11 +111,11 @@
                     .with_code("E0499")
                     .with_message("cannot borrow `v` as mutable more than once at a time")
                     .with_labels(vec![
-                        Label::primary((), 71..72)
+                        Label::primary(file_id1, 71..72)
                             .with_message("second mutable borrow occurs here"),
-                        Label::secondary((), 64..65)
+                        Label::secondary(file_id1, 64..65)
                             .with_message("first borrow later used by call"),
-                        Label::secondary((), 66..70)
+                        Label::secondary(file_id1, 66..70)
                             .with_message("first mutable borrow occurs here"),
                     ]),
                 Diagnostic::error()
@@ -122,7 +125,149 @@
                     ]),
             ];
 
-            TestData { files: file, diagnostics }
+            TestData { files, diagnostics }
+        };
+    }
+
+    test_emit!(rich_color);
+    test_emit!(short_color);
+    test_emit!(rich_no_color);
+    test_emit!(short_no_color);
+}
+
+/// Based on:
+/// - https://github.com/rust-lang/rust/blob/c20d7eecbc0928b57da8fe30b2ef8528e2bdd5be/src/test/ui/nested_impl_trait.stderr
+/// - https://github.com/rust-lang/rust/blob/c20d7eecbc0928b57da8fe30b2ef8528e2bdd5be/src/test/ui/typeck/typeck_type_placeholder_item.stderr
+/// - https://github.com/rust-lang/rust/blob/c20d7eecbc0928b57da8fe30b2ef8528e2bdd5be/src/test/ui/no_send_res_ports.stderr
+mod overlapping {
+    use super::*;
+
+    lazy_static::lazy_static! {
+        static ref TEST_DATA: TestData<'static, SimpleFiles<&'static str, String>> = {
+            let mut files = SimpleFiles::new();
+
+            let file_id1 = files.add(
+                "nested_impl_trait.rs",
+                unindent::unindent(r#"
+                    use std::fmt::Debug;
+
+                    fn fine(x: impl Into<u32>) -> impl Into<u32> { x }
+
+                    fn bad_in_ret_position(x: impl Into<u32>) -> impl Into<impl Debug> { x }
+                "#),
+            );
+            let file_id2 = files.add(
+                "typeck_type_placeholder_item.rs",
+                unindent::unindent(r#"
+                    fn fn_test1() -> _ { 5 }
+                    fn fn_test2(x: i32) -> (_, _) { (x, x) }
+                "#),
+            );
+            let file_id3 = files.add(
+                "libstd/thread/mod.rs",
+                unindent::unindent(r#"
+                    #[stable(feature = "rust1", since = "1.0.0")]
+                    pub fn spawn<F, T>(self, f: F) -> io::Result<JoinHandle<T>>
+                    where
+                        F: FnOnce() -> T,
+                        F: Send + 'static,
+                        T: Send + 'static,
+                    {
+                        unsafe { self.spawn_unchecked(f) }
+                    }
+                "#),
+            );
+            let file_id4 = files.add(
+                "no_send_res_ports.rs",
+                unindent::unindent(r#"
+                    use std::thread;
+                    use std::rc::Rc;
+
+                    #[derive(Debug)]
+                    struct Port<T>(Rc<T>);
+
+                    fn main() {
+                        #[derive(Debug)]
+                        struct Foo {
+                            _x: Port<()>,
+                        }
+
+                        impl Drop for Foo {
+                            fn drop(&mut self) {}
+                        }
+
+                        fn foo(x: Port<()>) -> Foo {
+                            Foo {
+                                _x: x
+                            }
+                        }
+
+                        let x = foo(Port(Rc::new(())));
+
+                        thread::spawn(move|| {
+                            let y = x;
+                            println!("{:?}", y);
+                        });
+                    }
+                "#),
+            );
+
+            let diagnostics = vec![
+                Diagnostic::error()
+                    .with_code("E0666")
+                    .with_message("nested `impl Trait` is not allowed")
+                    .with_labels(vec![
+                        Label::primary(file_id1, 129..139)
+                            .with_message("nested `impl Trait` here"),
+                        Label::secondary(file_id1, 119..140)
+                            .with_message("outer `impl Trait`"),
+                    ]),
+                Diagnostic::error()
+                    .with_code("E0121")
+                    .with_message("the type placeholder `_` is not allowed within types on item signatures")
+                        .with_labels(vec![
+                            Label::primary(file_id2, 17..18)
+                                .with_message("not allowed in type signatures"),
+                            Label::secondary(file_id2, 17..18)
+                                .with_message("help: replace with the correct return type: `i32`"),
+                        ]),
+                Diagnostic::error()
+                    .with_code("E0121")
+                    .with_message("the type placeholder `_` is not allowed within types on item signatures")
+                        .with_labels(vec![
+                            Label::primary(file_id2, 49..50)
+                                .with_message("not allowed in type signatures"),
+                            Label::primary(file_id2, 52..53)
+                                .with_message("not allowed in type signatures"),
+                            Label::secondary(file_id2, 48..54)
+                                .with_message("help: replace with the correct return type: `(i32, i32)`"),
+                        ]),
+                Diagnostic::error()
+                    .with_code("E0277")
+                    .with_message("`std::rc::Rc<()>` cannot be sent between threads safely")
+                    .with_labels(vec![
+                        Label::primary(file_id4, 339..352)
+                            .with_message("`std::rc::Rc<()>` cannot be sent between threads safely"),
+                        Label::secondary(file_id4, 353..416)
+                            .with_message("within this `[closure@no_send_res_ports.rs:29:19: 33:6 x:main::Foo]`"),
+                        Label::secondary(file_id3, 141..145)
+                            .with_message("required by this bound in `std::thread::spawn`"),
+                    ])
+                    .with_notes(vec![
+                        "help: within `[closure@no_send_res_ports.rs:29:19: 33:6 x:main::Foo]`, the trait `std::marker::Send` is not implemented for `std::rc::Rc<()>`".to_owned(),
+                        "note: required because it appears within the type `Port<()>`".to_owned(),
+                        "note: required because it appears within the type `main::Foo`".to_owned(),
+                        "note: required because it appears within the type `[closure@no_send_res_ports.rs:29:19: 33:6 x:main::Foo]`".to_owned(),
+                    ]),
+                Diagnostic::error()
+                    .with_message("aborting due 5 previous errors")
+                    .with_notes(vec![
+                        "Some errors have detailed explanations: E0121, E0277, E0666.".to_owned(),
+                        "For more information about an error, try `rustc --explain E0121`.".to_owned(),
+                    ]),
+            ];
+
+            TestData { files, diagnostics }
         };
     }
 
@@ -185,7 +330,7 @@
 
     lazy_static::lazy_static! {
         static ref TEST_DATA: TestData<'static, SimpleFile<&'static str, &'static str>> = {
-            let file = SimpleFile::new("hello", "Hello world!\nBye world!");
+            let file = SimpleFile::new("hello", "Hello world!\nBye world!\n   ");
             let eof = file.source().len();
 
             let diagnostics = vec![
@@ -196,6 +341,9 @@
                     .with_message("end of line")
                     .with_labels(vec![Label::primary((), 12..12).with_message("end of line")]),
                 Diagnostic::note()
+                    .with_message("end of line")
+                    .with_labels(vec![Label::primary((), 23..23).with_message("end of line")]),
+                Diagnostic::note()
                     .with_message("end of file")
                     .with_labels(vec![Label::primary((), eof..eof).with_message("end of file")]),
             ];
@@ -483,10 +631,7 @@
     fn tab_width_default_no_color() {
         let config = TEST_CONFIG.clone();
 
-        insta::assert_snapshot!(
-            "tab_width_default_no_color",
-            TEST_DATA.emit_no_color(&config)
-        );
+        insta::assert_snapshot!(TEST_DATA.emit_no_color(&config));
     }
 
     #[test]
@@ -510,7 +655,84 @@
     }
 }
 
-/// Based on: https://github.com/TheSamsa/rust/blob/75cf41afb468152611212271bae026948cd3ba46/src/test/ui/codemap_tests/unicode.stderr
+mod tab_columns {
+    use super::*;
+
+    lazy_static::lazy_static! {
+        static ref TEST_DATA: TestData<'static, SimpleFiles<&'static str, String>> = {
+            let mut files = SimpleFiles::new();
+
+            let source = [
+                "\thello",
+                "∙\thello",
+                "∙∙\thello",
+                "∙∙∙\thello",
+                "∙∙∙∙\thello",
+                "∙∙∙∙∙\thello",
+                "∙∙∙∙∙∙\thello",
+            ].join("\n");
+            let hello_ranges = source
+                .match_indices("hello")
+                .map(|(start, hello)| start..(start+hello.len()))
+                .collect::<Vec<_>>();
+
+            let file_id = files.add("tab_columns", source);
+
+            let diagnostics = vec![
+                Diagnostic::warning()
+                    .with_message("tab test")
+                    .with_labels(
+                        hello_ranges
+                            .into_iter()
+                            .map(|range| Label::primary(file_id, range))
+                            .collect(),
+                    ),
+            ];
+
+            TestData { files, diagnostics }
+        };
+    }
+
+    #[test]
+    fn tab_width_default_no_color() {
+        let config = TEST_CONFIG.clone();
+
+        insta::assert_snapshot!(TEST_DATA.emit_no_color(&config));
+    }
+
+    #[test]
+    fn tab_width_2_no_color() {
+        let config = Config {
+            tab_width: 2,
+            ..TEST_CONFIG.clone()
+        };
+
+        insta::assert_snapshot!(TEST_DATA.emit_no_color(&config));
+    }
+
+    #[test]
+    fn tab_width_3_no_color() {
+        let config = Config {
+            tab_width: 3,
+            ..TEST_CONFIG.clone()
+        };
+
+        insta::assert_snapshot!(TEST_DATA.emit_no_color(&config));
+    }
+
+    #[test]
+    fn tab_width_6_no_color() {
+        let config = Config {
+            tab_width: 6,
+            ..TEST_CONFIG.clone()
+        };
+
+        insta::assert_snapshot!(TEST_DATA.emit_no_color(&config));
+    }
+}
+
+/// Based on:
+/// - https://github.com/TheSamsa/rust/blob/75cf41afb468152611212271bae026948cd3ba46/src/test/ui/codemap_tests/unicode.stderr
 mod unicode {
     use super::*;
 
@@ -595,14 +817,26 @@
                     .with_labels(vec![
                         Label::primary((), invalid_start..invalid_end)
                             .with_message("Invalid jump"),
+                    ]),
+                Diagnostic::note()
+                    .with_message("invalid unicode range")
+                    .with_labels(vec![
                         Label::secondary((), invalid_start.."🐄".len())
                             .with_message("Cow range does not start at boundary."),
+                    ]),
+                Diagnostic::note()
+                    .with_message("invalid unicode range")
+                    .with_labels(vec![
                         Label::secondary((), "🐄🌑".len().."🐄🌑🐄".len() - 1)
                             .with_message("Cow range does not end at boundary."),
+                    ]),
+                Diagnostic::note()
+                    .with_message("invalid unicode range")
+                    .with_labels(vec![
                         Label::secondary((), invalid_start.."🐄🌑🐄".len() - 1)
                             .with_message("Cow does not start or end at boundary."),
-
-                    ])];
+                    ]),
+            ];
             TestData{files: file, diagnostics }
         };
     }