PR16090: C++1y: treat undeduced 'auto' as a literal type, so that constexpr
function templates can use it as a return type.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@182433 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Type.cpp b/lib/AST/Type.cpp
index eacf367..004e31a 100644
--- a/lib/AST/Type.cpp
+++ b/lib/AST/Type.cpp
@@ -1196,6 +1196,11 @@
return true;
}
+ // If this type hasn't been deduced yet, then conservatively assume that
+ // it'll work out to be a literal type.
+ if (isa<AutoType>(BaseTy->getCanonicalTypeInternal()))
+ return true;
+
return false;
}
diff --git a/test/SemaCXX/constant-expression-cxx1y.cpp b/test/SemaCXX/constant-expression-cxx1y.cpp
index ea0c9e6..23b5d0b 100644
--- a/test/SemaCXX/constant-expression-cxx1y.cpp
+++ b/test/SemaCXX/constant-expression-cxx1y.cpp
@@ -708,3 +708,10 @@
static_assert(test_copy("hello world", 10), "");
static_assert(test_copy("hello world", 10), "");
}
+
+namespace deduced_return_type {
+ constexpr auto f() { return 0; }
+ template<typename T> constexpr auto g(T t) { return t; }
+ static_assert(f() == 0, "");
+ static_assert(g(true), "");
+}
