[PATCH] D103760: [clang] use correct builtin type for defaulted comparison analyzer

[Matheus Izvekov via Phabricator via cfe-commits]

mizvekov created this revision.
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Fixes PR50591.

When analyzing classes with members which have user-defined conversion
operators to builtin types, the defaulted comparison analyzer was
picking the member type instead of the type for the builtin operator
which was selected as the best match.

This could either result in wrong comparison category being selected,
or a crash when runtime checks are enabled.

Signed-off-by: Matheus Izvekov <mizvekov at gmail.com>


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D103760

Files:
  clang/lib/Sema/SemaDeclCXX.cpp
  clang/test/CXX/class/class.compare/class.spaceship/p2.cpp


Index: clang/test/CXX/class/class.compare/class.spaceship/p2.cpp
===================================================================
--- clang/test/CXX/class/class.compare/class.spaceship/p2.cpp
+++ clang/test/CXX/class/class.compare/class.spaceship/p2.cpp
@@ -172,3 +172,23 @@
     int C::*x;                                   // expected-note {{because there is no viable three-way comparison function for member 'x'}}
   };
 }
+
+namespace PR50591 {
+  struct a1 {
+    operator int() const;
+  };
+  struct b1 {
+    auto operator<=>(b1 const &) const = default;
+    a1 f;
+  };
+  std::strong_ordering cmp_b1 = b1() <=> b1();
+
+  struct a2 {
+    operator float() const;
+  };
+  struct b2 {
+    auto operator<=>(b2 const &) const = default;
+    a2 f;
+  };
+  std::partial_ordering cmp_b2 = b2() <=> b2();
+}
Index: clang/lib/Sema/SemaDeclCXX.cpp
===================================================================
--- clang/lib/Sema/SemaDeclCXX.cpp
+++ clang/lib/Sema/SemaDeclCXX.cpp
@@ -7861,8 +7861,13 @@
             return Result::deleted();
           }
         } else {
+          QualType T = Best->BuiltinParamTypes[0];
+          assert(T == Best->BuiltinParamTypes[1] &&
+                 "builtin comparison for different types?");
+          assert(Best->BuiltinParamTypes[2].isNull() &&
+                 "invalid builtin comparison");
           Optional<ComparisonCategoryType> Cat =
-              getComparisonCategoryForBuiltinCmp(Args[0]->getType());
+              getComparisonCategoryForBuiltinCmp(T);
           assert(Cat && "no category for builtin comparison?");
           R.Category = *Cat;
         }


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