[Clang] use begin member expr location for call expr with deducing this (llvm#117345)

Fixes llvm#116928

Author: a-tarasyuk

clang/docs/ReleaseNotes.rst

@@ -732,6 +732,8 @@ Bug Fixes to AST Handling
   sometimes incorrectly return null even if a comment was present. (#GH108145)
 - Clang now correctly parses the argument of the ``relates``, ``related``, ``relatesalso``,
   and ``relatedalso`` comment commands.
+- Clang now uses the location of the begin of the member expression for ``CallExpr``
+  involving deduced ``this``. (#GH116928)
 
 Miscellaneous Bug Fixes
 ^^^^^^^^^^^^^^^^^^^^^^^

clang/lib/Sema/SemaOverload.cpp

@@ -15565,7 +15565,7 @@ ExprResult Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE,
     // Build the actual expression node.
     ExprResult FnExpr =
         CreateFunctionRefExpr(*this, Method, FoundDecl, MemExpr,
-                              HadMultipleCandidates, MemExpr->getExprLoc());
+                              HadMultipleCandidates, MemExpr->getBeginLoc());
     if (FnExpr.isInvalid())
       return ExprError();
 

clang/test/AST/ast-dump-cxx2b-deducing-this.cpp

@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -std=c++2b -ast-dump %s | FileCheck -strict-whitespace %s
+
+namespace GH116928 {
+struct S {
+  int f(this S&);
+};
+
+int main() {
+  S s;
+  int x = s.f();
+  // CHECK: CallExpr 0x{{[^ ]*}} <col:11, col:15> 'int
+  // CHECK-NEXT: |-ImplicitCastExpr 0x{{[^ ]*}} <col:11> 'int (*)(S &)' <FunctionToPointerDecay>
+  // CHECK-NEXT: | `-DeclRefExpr 0x{{[^ ]*}} <col:11> 'int (S &)' lvalue CXXMethod 0x{{[^ ]*}} 'f' 'int (S &)'
+}
+}