[clang] 11bb5e5 - In ExprRequirement building, treat OverloadExpr as dependent (#66683)

[via cfe-commits]

Author: Erich Keane
Date: 2023-09-19T08:31:18-07:00
New Revision: 11bb5e55dc1fa00f522ce73805d36e0b76819386

URL: https://github.com/llvm/llvm-project/commit/11bb5e55dc1fa00f522ce73805d36e0b76819386
DIFF: https://github.com/llvm/llvm-project/commit/11bb5e55dc1fa00f522ce73805d36e0b76819386.diff

LOG: In ExprRequirement building, treat OverloadExpr as dependent (#66683)

As reported in #66612, we aren't correctly treating the placeholder
expression type correctly, so we ended up trying to get a reference
version of it, and this resulted in an assertion, since the placeholder
type cannot have a reference added.

Fixes: #66612

Added: 
    

Modified: 
    clang/docs/ReleaseNotes.rst
    clang/lib/Sema/SemaExprCXX.cpp
    clang/test/SemaTemplate/concepts.cpp

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 30c29a5d6db6f5e..ba91f9481fe988a 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -305,6 +305,9 @@ Bug Fixes to C++ Support
   that contains a `return`.
   (`#48527 <https://github.com/llvm/llvm-project/issues/48527>`_)
 
+- Clang now no longer asserts when an UnresolvedLookupExpr is used as an
+  expression requirement. (`#66612 https://github.com/llvm/llvm-project/issues/66612`)
+
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
 - Fixed an import failure of recursive friend class template.

diff  --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index bb4ef065d5c72aa..77289595972e3cf 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -9063,7 +9063,8 @@ Sema::BuildExprRequirement(
     concepts::ExprRequirement::ReturnTypeRequirement ReturnTypeRequirement) {
   auto Status = concepts::ExprRequirement::SS_Satisfied;
   ConceptSpecializationExpr *SubstitutedConstraintExpr = nullptr;
-  if (E->isInstantiationDependent() || ReturnTypeRequirement.isDependent())
+  if (E->isInstantiationDependent() || E->getType()->isPlaceholderType() ||
+      ReturnTypeRequirement.isDependent())
     Status = concepts::ExprRequirement::SS_Dependent;
   else if (NoexceptLoc.isValid() && canThrow(E) == CanThrowResult::CT_Can)
     Status = concepts::ExprRequirement::SS_NoexceptNotMet;

diff  --git a/clang/test/SemaTemplate/concepts.cpp b/clang/test/SemaTemplate/concepts.cpp
index 891b45aa5789296..68050e0f09e248a 100644
--- a/clang/test/SemaTemplate/concepts.cpp
+++ b/clang/test/SemaTemplate/concepts.cpp
@@ -1031,3 +1031,20 @@ void test() {
     fff(42UL); // expected-error {{no matching function}}
 }
 }
+
+namespace GH66612 {
+  template<typename C>
+    auto end(C c) ->int;
+
+  template <typename T>
+    concept Iterator = true;
+
+  template <typename CT>
+    concept Container = requires(CT b) {
+        { end } -> Iterator; // #66612GH_END
+    };
+
+  static_assert(Container<int>);// expected-error{{static assertion failed}}
+  // expected-note at -1{{because 'int' does not satisfy 'Container'}}
+  // expected-note@#66612GH_END{{because 'end' would be invalid: reference to overloaded function could not be resolved; did you mean to call it?}}
+}