[PATCH] D153690: [clang][Sema] Remove dead diagnostic for loss of __unaligned qualifier

[Takuya Shimizu via Phabricator via cfe-commits]

hazohelet updated this revision to Diff 535010.
hazohelet added a comment.

Added release note and test because this change is not NFC


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D153690/new/

https://reviews.llvm.org/D153690

Files:
  clang/docs/ReleaseNotes.rst
  clang/include/clang/Basic/DiagnosticSemaKinds.td
  clang/lib/Sema/SemaOverload.cpp
  clang/test/SemaCXX/MicrosoftExtensions.cpp


Index: clang/test/SemaCXX/MicrosoftExtensions.cpp
===================================================================
--- clang/test/SemaCXX/MicrosoftExtensions.cpp
+++ clang/test/SemaCXX/MicrosoftExtensions.cpp
@@ -68,19 +68,23 @@
 void (aligned_type4::*__unaligned p4_aligned_type4)();
 
 // Check that __unaligned qualifier can be used for overloading
-void foo_unaligned(int *arg) {}
-void foo_unaligned(__unaligned int *arg) {}
+void foo_unaligned(int *arg) {} // expected-note {{not viable: 1st argument ('const __unaligned int *') would lose const qualifier}}
+void foo_unaligned(__unaligned int *arg) {} // expected-note {{not viable: 1st argument ('const __unaligned int *') would lose const qualifier}}
 void foo_unaligned(int arg) {} // expected-note {{previous definition is here}}
-void foo_unaligned(__unaligned int arg) {} // expected-error {{redefinition of 'foo_unaligned'}}
+void foo_unaligned(__unaligned int arg) {} // expected-error {{redefinition of 'foo_unaligned'}} \
+                                           // expected-note {{not viable: no known conversion from 'const __unaligned int *' to '__unaligned int'}}
 class A_unaligned {};
 class B_unaligned : public A_unaligned {};
-int foo_unaligned(__unaligned A_unaligned *arg) { return 0; }
-void *foo_unaligned(B_unaligned *arg) { return 0; }
+int foo_unaligned(__unaligned A_unaligned *arg) { return 0; } // expected-note {{not viable: no known conversion from 'const __unaligned int *' to '__unaligned A_unaligned *'}}
+void *foo_unaligned(B_unaligned *arg) { return 0; } // expected-note {{not viable: no known conversion from 'const __unaligned int *' to 'B_unaligned *'}}
 
 void test_unaligned() {
   int *p1 = 0;
   foo_unaligned(p1);
 
+  const __unaligned int *const_p1 = 0;
+  foo_unaligned(const_p1); // expected-error {{no matching function for call to 'foo_unaligned'}}
+
   __unaligned int *p2 = 0;
   foo_unaligned(p2);
 
Index: clang/lib/Sema/SemaOverload.cpp
===================================================================
--- clang/lib/Sema/SemaOverload.cpp
+++ clang/lib/Sema/SemaOverload.cpp
@@ -10821,15 +10821,6 @@
       return;
     }
 
-    if (FromQs.hasUnaligned() != ToQs.hasUnaligned()) {
-      S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_unaligned)
-          << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
-          << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
-          << FromQs.hasUnaligned() << I + 1;
-      MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
-      return;
-    }
-
     unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers();
     assert(CVR && "expected qualifiers mismatch");
 
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -4700,9 +4700,6 @@
     "%select{const|restrict|const and restrict|volatile|const and volatile|"
     "volatile and restrict|const, volatile, and restrict}4 qualifier"
     "%select{||s||s|s|s}4">;
-def note_ovl_candidate_bad_unaligned : Note<
-    "candidate %sub{select_ovl_candidate_kind}0,1,2 not viable: "
-    "%ordinal5 argument (%3) would lose __unaligned qualifier">;
 def note_ovl_candidate_bad_base_to_derived_conv : Note<
     "candidate %sub{select_ovl_candidate_kind}0,1,2 not viable: "
     "cannot %select{convert from|convert from|bind}3 "
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -375,6 +375,8 @@
   by making use of the syntactical structure of function calls. This avoids display
   of syntactically invalid codes in diagnostics.
   (`#57081: <https://github.com/llvm/llvm-project/issues/57081>`_)
+- Clang no longer emits inappropriate notes about the loss of ``__unaligned`` qualifier
+  on overload resolution, when the actual reason for the failure is loss of other qualifiers.
 
 Bug Fixes in This Version
 -------------------------


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