[clang] [Clang] fix missing source location for ':' error in macro-expanded case statements (PR #143460)

[Oleksandr T. via cfe-commits]

https://github.com/a-tarasyuk updated https://github.com/llvm/llvm-project/pull/143460

>From dd4953312066cb63ae1a3882270426c87b1f5b7a Mon Sep 17 00:00:00 2001
From: Oleksandr Tarasiuk <oleksandr.tarasiuk at outlook.com>
Date: Tue, 10 Jun 2025 02:47:51 +0300
Subject: [PATCH 1/2] [Clang] fix missing source location for ':' error in
 macro-expanded case statements

---
 clang/docs/ReleaseNotes.rst                        |  1 +
 clang/include/clang/Basic/DiagnosticCommonKinds.td |  1 +
 clang/lib/Parse/ParseStmt.cpp                      | 14 ++++++++++++++
 clang/test/Parser/switch-recovery.cpp              | 13 +++++++++++++
 4 files changed, 29 insertions(+)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 322686fce0b04..0ecbb4864050c 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -689,6 +689,7 @@ Bug Fixes in This Version
 - Fixed type mismatch error when 'builtin-elementwise-math' arguments have different qualifiers, this should be well-formed. (#GH141397)
 - Constant evaluation now correctly runs the destructor of a variable declared in
   the second clause of a C-style ``for`` loop. (#GH139818)
+- Fixed incorrect diagnostic location for missing ``:`` in case statements expanded from macros. (#GH143216)
 
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/include/clang/Basic/DiagnosticCommonKinds.td b/clang/include/clang/Basic/DiagnosticCommonKinds.td
index 0bd8a423c393e..ee8fc66c1822c 100644
--- a/clang/include/clang/Basic/DiagnosticCommonKinds.td
+++ b/clang/include/clang/Basic/DiagnosticCommonKinds.td
@@ -83,6 +83,7 @@ let CategoryName = "Parse Issue" in {
 def err_expected : Error<"expected %0">;
 def err_expected_either : Error<"expected %0 or %1">;
 def err_expected_after : Error<"expected %1 after %0">;
+def note_macro_expansion : Note<"expanded from macro '%0'">;
 
 def err_param_redefinition : Error<"redefinition of parameter %0">;
 def warn_method_param_redefinition : Warning<"redefinition of method parameter %0">;
diff --git a/clang/lib/Parse/ParseStmt.cpp b/clang/lib/Parse/ParseStmt.cpp
index c788723023c8b..5db6dd36f840b 100644
--- a/clang/lib/Parse/ParseStmt.cpp
+++ b/clang/lib/Parse/ParseStmt.cpp
@@ -833,9 +833,23 @@ StmtResult Parser::ParseCaseStatement(ParsedStmtContext StmtCtx,
           << FixItHint::CreateReplacement(ColonLoc, ":");
     } else {
       SourceLocation ExpectedLoc = PP.getLocForEndOfToken(PrevTokLocation);
+      SourceLocation ExprLoc =
+          LHS.get() ? LHS.get()->getExprLoc() : SourceLocation();
+
+      if (ExpectedLoc.isInvalid() && ExprLoc.isMacroID()) {
+        ExpectedLoc = PP.getSourceManager().getSpellingLoc(ExprLoc);
+      }
+
       Diag(ExpectedLoc, diag::err_expected_after)
           << "'case'" << tok::colon
           << FixItHint::CreateInsertion(ExpectedLoc, ":");
+
+      if (ExprLoc.isMacroID()) {
+        Diag(ExprLoc, diag::note_macro_expansion)
+            << Lexer::getImmediateMacroNameForDiagnostics(
+                   ExprLoc, PP.getSourceManager(), getLangOpts());
+      }
+
       ColonLoc = ExpectedLoc;
     }
 
diff --git a/clang/test/Parser/switch-recovery.cpp b/clang/test/Parser/switch-recovery.cpp
index baf703cd03aed..5966b04b3f636 100644
--- a/clang/test/Parser/switch-recovery.cpp
+++ b/clang/test/Parser/switch-recovery.cpp
@@ -229,3 +229,16 @@ void fn1() {
     }
 } // expected-error{{expected statement}}
 }
+
+namespace GH143216 {
+#define FOO 1 case 3: // expected-error {{expected ':' after 'case'}}
+
+int f(int x) {
+  switch (x) {
+  case FOO // expected-note {{expanded from macro 'FOO'}}
+    return 0;
+  default:
+    return 1;
+  }
+}
+}

>From 4126f9b4f2ec071b45694ddeeec8f37886d1d515 Mon Sep 17 00:00:00 2001
From: Oleksandr Tarasiuk <oleksandr.tarasiuk at outlook.com>
Date: Tue, 10 Jun 2025 16:18:29 +0300
Subject: [PATCH 2/2] remove duplicate note diagnostic

---
 clang/lib/Parse/ParseStmt.cpp         | 16 ++++------------
 clang/test/Parser/switch-recovery.cpp |  2 +-
 2 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/clang/lib/Parse/ParseStmt.cpp b/clang/lib/Parse/ParseStmt.cpp
index 5db6dd36f840b..c23a596183cd5 100644
--- a/clang/lib/Parse/ParseStmt.cpp
+++ b/clang/lib/Parse/ParseStmt.cpp
@@ -833,22 +833,14 @@ StmtResult Parser::ParseCaseStatement(ParsedStmtContext StmtCtx,
           << FixItHint::CreateReplacement(ColonLoc, ":");
     } else {
       SourceLocation ExpectedLoc = PP.getLocForEndOfToken(PrevTokLocation);
-      SourceLocation ExprLoc =
-          LHS.get() ? LHS.get()->getExprLoc() : SourceLocation();
-
-      if (ExpectedLoc.isInvalid() && ExprLoc.isMacroID()) {
-        ExpectedLoc = PP.getSourceManager().getSpellingLoc(ExprLoc);
+      if (ExpectedLoc.isInvalid() && LHS.get()) {
+        ExpectedLoc =
+            PP.getSourceManager().getSpellingLoc(LHS.get()->getExprLoc());
       }
 
       Diag(ExpectedLoc, diag::err_expected_after)
           << "'case'" << tok::colon
-          << FixItHint::CreateInsertion(ExpectedLoc, ":");
-
-      if (ExprLoc.isMacroID()) {
-        Diag(ExprLoc, diag::note_macro_expansion)
-            << Lexer::getImmediateMacroNameForDiagnostics(
-                   ExprLoc, PP.getSourceManager(), getLangOpts());
-      }
+          << FixItHint::CreateInsertion(ExpectedLoc, tok::getTokenName(tok::colon));
 
       ColonLoc = ExpectedLoc;
     }
diff --git a/clang/test/Parser/switch-recovery.cpp b/clang/test/Parser/switch-recovery.cpp
index 5966b04b3f636..a9c9d8fddc009 100644
--- a/clang/test/Parser/switch-recovery.cpp
+++ b/clang/test/Parser/switch-recovery.cpp
@@ -235,7 +235,7 @@ namespace GH143216 {
 
 int f(int x) {
   switch (x) {
-  case FOO // expected-note {{expanded from macro 'FOO'}}
+  case FOO
     return 0;
   default:
     return 1;