[llvm-branch-commits] [clang] [clang] add fallback to expr in the template differ when comparing ValueDecl (PR #93266)

[via llvm-branch-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Matheus Izvekov (mizvekov)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/93266.diff


3 Files Affected:

- (modified) clang/docs/ReleaseNotes.rst (+1) 
- (modified) clang/lib/AST/ASTDiagnostic.cpp (+5) 
- (modified) clang/test/Misc/diag-template-diffing-cxx26.cpp (+2-2) 


``````````diff
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 6e8687fadc6f7..5e217a76c81a1 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -784,6 +784,7 @@ Miscellaneous Bug Fixes
 - Fixed an infinite recursion in ASTImporter, on return type declared inside
   body of C++11 lambda without trailing return (#GH68775).
 - Fixed declaration name source location of instantiated function definitions (GH71161).
+- Missing fallback to expression in the template differ when comparing ValueDecls.
 
 Miscellaneous Clang Crashes Fixed
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/AST/ASTDiagnostic.cpp b/clang/lib/AST/ASTDiagnostic.cpp
index 7e4a5709a44ce..1885b21178666 100644
--- a/clang/lib/AST/ASTDiagnostic.cpp
+++ b/clang/lib/AST/ASTDiagnostic.cpp
@@ -1936,6 +1936,11 @@ class TemplateDiff {
       return;
     }
 
+    if (E) {
+      PrintExpr(E);
+      return;
+    }
+
     OS << "(no argument)";
   }
 
diff --git a/clang/test/Misc/diag-template-diffing-cxx26.cpp b/clang/test/Misc/diag-template-diffing-cxx26.cpp
index cc174d6c334fb..2b6dd86a9885d 100644
--- a/clang/test/Misc/diag-template-diffing-cxx26.cpp
+++ b/clang/test/Misc/diag-template-diffing-cxx26.cpp
@@ -19,10 +19,10 @@ namespace GH93068 {
     // expected-note@#A {{no known conversion from 'A<0>' to 'const A<&n[1]> &' for 1st argument}}
     // expected-note@#A {{no known conversion from 'A<0>' to 'A<&n[1]> &&' for 1st argument}}
 
-    // notree-error@#2 {{no viable conversion from 'A<n>' to 'A<(no argument)>'}}
+    // notree-error@#2 {{no viable conversion from 'A<n>' to 'A<n + 1>'}}
     /* tree-error@#2 {{no viable conversion
   A<
-    [n != (no argument)]>}}*/
+    [n != n + 1]>}}*/
 
     A<n + 1> v2 = A<n>(); // #2
     // expected-note@#A {{no known conversion from 'A<n>' to 'const A<&n[1]> &' for 1st argument}}

``````````

</details>


https://github.com/llvm/llvm-project/pull/93266