[clang] 5282d0c - [Clang] Skip invalid fields when synthesizing defaulted comparisons (#221570)

[via cfe-commits]

Author: Akash Manna
Date: 2026-09-09T06:43:10-07:00
New Revision: 5282d0c073beba1c2569222ede55ff943d46fcef

URL: https://github.com/llvm/llvm-project/commit/5282d0c073beba1c2569222ede55ff943d46fcef
DIFF: https://github.com/llvm/llvm-project/commit/5282d0c073beba1c2569222ede55ff943d46fcef.diff

LOG: [Clang] Skip invalid fields when synthesizing defaulted comparisons (#221570)

Fixes #194605

`CheckFieldDecl` already rejects `int [[clang::address_space(1)]] i;`
and marks the field invalid, but `DefaultedComparisonVisitor` still
visited it when synthesizing the defaulted `operator==`.
`BuildFieldReferenceExpr` then tripped the
`!MemberQuals.hasAddressSpace()` assertion. Both
`__is_trivially_equality_comparable(S)` and a plain `a == b` reach that
path.

`visitSubobjects` now skips invalid fields, the same way
`SpecialMemberVisitor` and the copy-assignment synthesis already do.
That covers the analyzer and the synthesizer together, and the assertion
stays in place since it still holds for valid code.

Added: 
    

Modified: 
    clang/docs/ReleaseNotes.md
    clang/lib/Sema/SemaDeclCXX.cpp
    clang/test/SemaCXX/cxx20-default-compare.cpp

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.md b/clang/docs/ReleaseNotes.md
index 0fb6dcf59d4c9..59b5c14c59242 100644
--- a/clang/docs/ReleaseNotes.md
+++ b/clang/docs/ReleaseNotes.md
@@ -652,6 +652,10 @@ features cannot lower the translation-unit ABI level;
 - Fixed a crash when a coroutine keyword appeared inside a mem-initializer on a
   function that is not a constructor. (#GH194298)
 
+- Fixed an assertion when a defaulted comparison operator was synthesized for a
+  class with an invalid non-static data member, such as one qualified with an
+  address space. (#GH194605)
+
 #### Bug Fixes to AST Handling
 
 - Fixed a non-deterministic ordering of unused local typedefs that made

diff  --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 4457ec58902d0..ac98bdaf22f0c 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -8203,6 +8203,8 @@ class DefaultedComparisonVisitor {
       //   Unnamed bit-fields are not members ...
       if (Field->isUnnamedBitField())
         continue;
+      if (Field->isInvalidDecl())
+        continue;
       // Recursively expand anonymous structs.
       if (Field->isAnonymousStructOrUnion()) {
         if (visitSubobjects(Results, Field->getType()->getAsCXXRecordDecl(),

diff  --git a/clang/test/SemaCXX/cxx20-default-compare.cpp b/clang/test/SemaCXX/cxx20-default-compare.cpp
index 4e93298bd17a9..b812aba747ac9 100644
--- a/clang/test/SemaCXX/cxx20-default-compare.cpp
+++ b/clang/test/SemaCXX/cxx20-default-compare.cpp
@@ -88,3 +88,12 @@ union A {
 A a;
 bool b = a == a;
 }
+
+namespace GH194605 {
+struct S {
+  int [[clang::address_space(1)]] i; // expected-error {{field may not be qualified with an address space}}
+  bool operator==(const S &) const = default;
+};
+
+static_assert(S{} == S{});
+}