PR25890: Fix incoherent error handling in PerformImplicitConversion and

CheckSingleAssignmentConstraints. These no longer produce ExprError() when they
have not emitted an error, and reliably inform the caller when they *have*
emitted an error.

This fixes some serious issues where we would fail to emit any diagnostic for
invalid code and then attempt to emit code for an invalid AST, and conversely
some issues where we would emit two diagnostics for the same problem.

llvm-svn: 283508

1 files changed, 5 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/ambig-user-defined-conversions.cpp b/clang/test/SemaCXX/ambig-user-defined-conversions.cpp
index 1a3c102f034..276c1b07b5d 100644
--- a/clang/test/SemaCXX/ambig-user-defined-conversions.cpp
+++ b/clang/test/SemaCXX/ambig-user-defined-conversions.cpp
@@ -65,3 +65,8 @@ namespace rdar8876150 {
 
   bool f(D d) { return !d; } // expected-error{{ambiguous conversion from derived class 'rdar8876150::D' to base class 'rdar8876150::A':}}
 }
+
+namespace assignment {
+  struct A { operator short(); operator bool(); }; // expected-note 2{{candidate}}
+  void f(int n, A a) { n = a; } // expected-error{{ambiguous}}
+}