[clang] [clang][Interp] Point 'declared here' note of invalid fns to definition (PR #102031)

[Timm Baeder via cfe-commits]

https://github.com/tbaederr created https://github.com/llvm/llvm-project/pull/102031

None

>From 23cad192584b903bfcd3c3ea0a6c0bfeb6951afe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbaeder at redhat.com>
Date: Mon, 5 Aug 2024 20:14:19 +0200
Subject: [PATCH] [clang][Interp] Point 'declared here' note of invalid fns to
 definition

---
 clang/lib/AST/Interp/Interp.cpp |  7 ++++++-
 clang/test/AST/Interp/cxx20.cpp | 17 +++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/clang/lib/AST/Interp/Interp.cpp b/clang/lib/AST/Interp/Interp.cpp
index 0252dd0d32699..0f72b860ddad7 100644
--- a/clang/lib/AST/Interp/Interp.cpp
+++ b/clang/lib/AST/Interp/Interp.cpp
@@ -628,7 +628,12 @@ bool CheckCallable(InterpState &S, CodePtr OpPC, const Function *F) {
 
       S.FFDiag(Loc, diag::note_constexpr_invalid_function, 1)
           << DiagDecl->isConstexpr() << (bool)CD << DiagDecl;
-      S.Note(DiagDecl->getLocation(), diag::note_declared_at);
+
+      if (DiagDecl->getDefinition())
+        S.Note(DiagDecl->getDefinition()->getLocation(),
+               diag::note_declared_at);
+      else
+        S.Note(DiagDecl->getLocation(), diag::note_declared_at);
     }
   } else {
     S.FFDiag(Loc, diag::note_invalid_subexpr_in_const_expr);
diff --git a/clang/test/AST/Interp/cxx20.cpp b/clang/test/AST/Interp/cxx20.cpp
index da80454b7a820..27dbd2818be60 100644
--- a/clang/test/AST/Interp/cxx20.cpp
+++ b/clang/test/AST/Interp/cxx20.cpp
@@ -841,3 +841,20 @@ namespace VariadicCallOperator {
   }
   constexpr int A = foo();
 }
+
+namespace DefinitionLoc {
+
+  struct NonConstexprCopy {
+    constexpr NonConstexprCopy() = default;
+    NonConstexprCopy(const NonConstexprCopy &);
+    constexpr NonConstexprCopy(NonConstexprCopy &&) = default;
+
+    int n = 42;
+  };
+
+  NonConstexprCopy::NonConstexprCopy(const NonConstexprCopy &) = default; // both-note {{here}}
+
+  constexpr NonConstexprCopy ncc1 = NonConstexprCopy(NonConstexprCopy());
+  constexpr NonConstexprCopy ncc2 = ncc1; // both-error {{constant expression}} \
+                                          // both-note {{non-constexpr constructor}}
+}