diff --git a/microfactory/microfactory.go b/microfactory/microfactory.go
index 845238b..a70d3c5 100644
--- a/microfactory/microfactory.go
+++ b/microfactory/microfactory.go
@@ -400,7 +400,7 @@
 		"-o", p.output,
 		"-p", p.Name,
 		"-complete", "-pack", "-nolocalimports")
-	if !isGo18 {
+	if !isGo18 && !config.Race {
 		cmd.Args = append(cmd.Args, "-c", fmt.Sprintf("%d", runtime.NumCPU()))
 	}
 	if config.Race {
diff --git a/name_interface.go b/name_interface.go
index 6743f0c..1849e9d 100644
--- a/name_interface.go
+++ b/name_interface.go
@@ -126,20 +126,22 @@
 func (s *SimpleNameInterface) Rename(oldName string, newName string, namespace Namespace) (errs []error) {
 	existingGroup, exists := s.modules[newName]
 	if exists {
-		errs = append(errs,
+		return []error{
 			// seven characters at the start of the second line to align with the string "error: "
 			fmt.Errorf("renaming module %q to %q conflicts with existing module\n"+
 				"       %s <-- existing module defined here",
 				oldName, newName, existingGroup.modules[0].pos),
-		)
-		return errs
+		}
 	}
 
-	group := s.modules[oldName]
+	group, exists := s.modules[oldName]
+	if !exists {
+		return []error{fmt.Errorf("module %q to renamed to %q doesn't exist", oldName, newName)}
+	}
 	s.modules[newName] = group
 	delete(s.modules, group.name)
 	group.name = newName
-	return []error{}
+	return nil
 }
 
 func (s *SimpleNameInterface) AllModules() []ModuleGroup {
diff --git a/parser/printer.go b/parser/printer.go
index d3aad4a..ac7ffe1 100644
--- a/parser/printer.go
+++ b/parser/printer.go
@@ -173,15 +173,34 @@
 }
 
 func (p *printer) printOperator(operator *Operator) {
+	p.printOperatorInternal(operator, true)
+}
+
+func (p *printer) printOperatorInternal(operator *Operator, allowIndent bool) {
 	p.printExpression(operator.Args[0])
 	p.requestSpace()
 	p.printToken(string(operator.Operator), operator.OperatorPos)
+
+	indented := false
 	if operator.Args[0].End().Line == operator.Args[1].Pos().Line {
 		p.requestSpace()
 	} else {
+		if allowIndent {
+			indented = true
+			p.indent(p.curIndent() + 4)
+		}
 		p.requestNewline()
 	}
-	p.printExpression(operator.Args[1])
+
+	if op, isOp := operator.Args[1].(*Operator); isOp {
+		p.printOperatorInternal(op, false)
+	} else {
+		p.printExpression(operator.Args[1])
+	}
+
+	if indented {
+		p.unindent(p.pos)
+	}
 }
 
 func (p *printer) printProperty(property *Property) {
diff --git a/parser/printer_test.go b/parser/printer_test.go
index a223fab..7289441 100644
--- a/parser/printer_test.go
+++ b/parser/printer_test.go
@@ -166,6 +166,22 @@
 	},
 	{
 		input: `
+foo {
+    bar: "b" +
+        "a" +
+	"z",
+}
+`,
+		output: `
+foo {
+    bar: "b" +
+        "a" +
+        "z",
+}
+`,
+	},
+	{
+		input: `
 foo = "stuff"
 bar = foo
 baz = foo + bar
@@ -194,6 +210,18 @@
 	},
 	{
 		input: `
+foo = "bar " +
+    "" +
+    "baz"
+`,
+		output: `
+foo = "bar " +
+    "" +
+    "baz"
+`,
+	},
+	{
+		input: `
 //test
 test /* test */ {
     srcs: [