[llvm-branch-commits] [clang] Backport/20.x: [Clang] Fix an incorrect assumption on getTemplatedDecl() (PR #131729)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Younan Zhang (zyn0217)

<details>
<summary>Changes</summary>

This backports d9110858ee because it fixes a regression introduced in 19 and we don't want it to persist in 20

---
Full diff: https://github.com/llvm/llvm-project/pull/131729.diff


3 Files Affected:

- (modified) clang/docs/ReleaseNotes.rst (+1) 
- (modified) clang/lib/Sema/SemaAccess.cpp (+2-2) 
- (modified) clang/test/SemaCXX/concept-crash-on-diagnostic.cpp (+12) 


``````````diff
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 02292c10e6964..dc63b5213c546 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -1059,6 +1059,7 @@ Bug Fixes to C++ Support
   corresponding to a pack parameter (#GH124715)
 - Clang is now better at keeping track of friend function template instance contexts. (#GH55509)
 - Fixed an integer overflow bug in computing template parameter depths when synthesizing CTAD guides. (#GH128691)
+- Fixed an incorrect pointer access when checking access-control on concepts. (#GH131530)
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaAccess.cpp b/clang/lib/Sema/SemaAccess.cpp
index f79d9a758e7af..6813786df3fc4 100644
--- a/clang/lib/Sema/SemaAccess.cpp
+++ b/clang/lib/Sema/SemaAccess.cpp
@@ -1518,8 +1518,8 @@ void Sema::HandleDelayedAccessCheck(DelayedDiagnostic &DD, Decl *D) {
   } else if (FunctionDecl *FN = dyn_cast<FunctionDecl>(D)) {
     DC = FN;
   } else if (TemplateDecl *TD = dyn_cast<TemplateDecl>(D)) {
-    if (isa<DeclContext>(TD->getTemplatedDecl()))
-      DC = cast<DeclContext>(TD->getTemplatedDecl());
+    if (auto *D = dyn_cast_if_present<DeclContext>(TD->getTemplatedDecl()))
+      DC = D;
   } else if (auto *RD = dyn_cast<RequiresExprBodyDecl>(D)) {
     DC = RD;
   }
diff --git a/clang/test/SemaCXX/concept-crash-on-diagnostic.cpp b/clang/test/SemaCXX/concept-crash-on-diagnostic.cpp
index 71e55c8290ee4..c38f8888075de 100644
--- a/clang/test/SemaCXX/concept-crash-on-diagnostic.cpp
+++ b/clang/test/SemaCXX/concept-crash-on-diagnostic.cpp
@@ -36,3 +36,15 @@ void function() {
 // expected-note@#4 {{candidate template ignored: constraints not satisfied [with IteratorL = Object *, IteratorR = Object *]}}
 // We don't know exactly the substituted type for `lhs == rhs`, thus a placeholder 'expr-type' is emitted.
 // expected-note@#3 {{because 'convertible_to<expr-type, bool>' would be invalid}}
+
+namespace GH131530 {
+
+class foo {
+  struct bar {}; // expected-note {{implicitly declared private}}
+};
+
+template <typename T>
+concept is_foo_concept = __is_same(foo::bar, T);
+// expected-error at -1 {{'bar' is a private member of 'GH131530::foo'}}
+
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/131729