[Clang] Rewrite SourceLocExpr in default args (#93383)

In order for their dependency to be computed correctly, SourceLocExpr
should refer to the context in which they are used.

Fixes #92680

Author: cor3ntin

clang/docs/ReleaseNotes.rst

@@ -794,6 +794,8 @@ Bug Fixes to C++ Support
   Fixes (#GH87210), (GH89541).
 - Clang no longer tries to check if an expression is immediate-escalating in an unevaluated context.
   Fixes (#GH91308).
+- Fix a crash caused by a regression in the handling of ``source_location``
+  in dependent contexts. Fixes (#GH92680).
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^

clang/lib/Sema/SemaExpr.cpp

@@ -5506,6 +5506,15 @@ struct EnsureImmediateInvocationInDefaultArgs
   // cause it to incorrectly point it to the outermost class
   // in the case of nested struct initialization.
   ExprResult TransformCXXThisExpr(CXXThisExpr *E) { return E; }
+
+  // Rewrite to source location to refer to the context in which they are used.
+  ExprResult TransformSourceLocExpr(SourceLocExpr *E) {
+    if (E->getParentContext() == SemaRef.CurContext)
+      return E;
+    return getDerived().RebuildSourceLocExpr(E->getIdentKind(), E->getType(),
+                                             E->getBeginLoc(), E->getEndLoc(),
+                                             SemaRef.CurContext);
+  }
 };
 
 ExprResult Sema::BuildCXXDefaultArgExpr(SourceLocation CallLoc,

clang/test/SemaCXX/source_location.cpp

@@ -912,3 +912,20 @@ auto g() {
 }
 
 }
+
+namespace GH92680 {
+
+struct IntConstuctible {
+  IntConstuctible(std::source_location = std::source_location::current());
+};
+
+template <typename>
+auto construct_at(IntConstuctible) -> decltype(IntConstuctible()) {
+  return {};
+}
+
+void test() {
+  construct_at<IntConstuctible>({});
+}
+
+}