commit 9ca395b5ade105aee63db20534d49a1c58ac76c7
Author: Haojian Wu <hokein.wu@gmail.com>
Date:   Mon Jul 10 18:22:12 2023 +0200

    [clang][AST] Propagate the contains-errors bit to DeclRefExpr from VarDecl's initializer.
    
    Similar to the https://reviews.llvm.org/D86048 (it only sets the bit for C++
    code), we propagate the contains-errors bit for C-code path.
    
    Fixes https://github.com/llvm/llvm-project/issues/50236
    Fixes https://github.com/llvm/llvm-project/issues/50243
    Fixes https://github.com/llvm/llvm-project/issues/48636
    Fixes https://github.com/llvm/llvm-project/issues/50320
    
    Differential Revision: https://reviews.llvm.org/D154861

diff --git clang/lib/AST/ComputeDependence.cpp clang/lib/AST/ComputeDependence.cpp
index 632f38f711fb..09df5401d669 100644
--- clang/lib/AST/ComputeDependence.cpp
+++ clang/lib/AST/ComputeDependence.cpp
@@ -489,7 +489,7 @@ ExprDependence clang::computeDependence(DeclRefExpr *E, const ASTContext &Ctx) {
   // more bullets here that we handle by treating the declaration as having a
   // dependent type if they involve a placeholder type that can't be deduced.]
   if (Type->isDependentType())
-    return Deps | ExprDependence::TypeValueInstantiation;
+    Deps |= ExprDependence::TypeValueInstantiation;
   else if (Type->isInstantiationDependentType())
     Deps |= ExprDependence::Instantiation;
 
@@ -525,13 +525,13 @@ ExprDependence clang::computeDependence(DeclRefExpr *E, const ASTContext &Ctx) {
   //   - it names a potentially-constant variable that is initialized with an
   //     expression that is value-dependent
   if (const auto *Var = dyn_cast<VarDecl>(Decl)) {
-    if (Var->mightBeUsableInConstantExpressions(Ctx)) {
-      if (const Expr *Init = Var->getAnyInitializer()) {
-        if (Init->isValueDependent())
-          Deps |= ExprDependence::ValueInstantiation;
-        if (Init->containsErrors())
-          Deps |= ExprDependence::Error;
-      }
+    if (const Expr *Init = Var->getAnyInitializer()) {
+      if (Init->containsErrors())
+        Deps |= ExprDependence::Error;
+
+      if (Var->mightBeUsableInConstantExpressions(Ctx) &&
+          Init->isValueDependent())
+        Deps |= ExprDependence::ValueInstantiation;
     }
 
     // - it names a static data member that is a dependent member of the
diff --git clang/test/SemaCXX/cxx11-crashes.cpp clang/test/SemaCXX/cxx11-crashes.cpp
index a15fea336f8c..11bc42315421 100644
--- clang/test/SemaCXX/cxx11-crashes.cpp
+++ clang/test/SemaCXX/cxx11-crashes.cpp
@@ -65,7 +65,7 @@ namespace b6981007 {
   struct S {}; // expected-note 3{{candidate}}
   void f() {
     S s(1, 2, 3); // expected-error {{no matching}}
-    for (auto x : s) { // expected-error {{invalid range expression of}}
+    for (auto x : s) {
       // We used to attempt to evaluate the initializer of this variable,
       // and crash because it has an undeduced type.
       const int &n(x);