[clang] 10b43f4 - [Clang][Sema] Correctly transform dependent operands of overloaded binary operator& (#97596)

[via cfe-commits]

Author: Krystian Stasiowski
Date: 2024-07-03T18:19:58-04:00
New Revision: 10b43f429a9f5cc7315c5b0490433647c9a93493

URL: https://github.com/llvm/llvm-project/commit/10b43f429a9f5cc7315c5b0490433647c9a93493
DIFF: https://github.com/llvm/llvm-project/commit/10b43f429a9f5cc7315c5b0490433647c9a93493.diff

LOG: [Clang][Sema] Correctly transform dependent operands of overloaded binary operator& (#97596)

Currently, `TreeTransform::TransformCXXOperatorCallExpr` calls
`TreeTransform::TransformAddressOfOperand` to transform the first
operand of a `CXXOperatorCallExpr` when its `OverloadOperatorKind` is
`OO_Amp` -- regardless of arity. This results in the first operand of
binary `operator&` being incorrectly transformed as if it was the
operand of the address of operator in cases such as the following:
```
struct A {
  int x;
};

void operator&(A, A);

template<typename T>
struct B {
  int f() {
    return T::x & 1; // invalid reference to 'A::x' is not diagnosed because 'T::x' is incorrectly transformed as if it was the operand of unary operator&
  }
};

template struct B<A>;
```
Prior to #92318 we would build a `CXXDependentScopeMemberExpr` for
`T::x` (as with most dependent qualified names that were not member
qualified names). Since `TreeTransform::TransformAddressOfOperand` only
differs from `TransformExpr` for `DependentScopeDeclRefExpr` and
`UnresolvedLookupExpr` operands, `T::x` was transformed "correctly". Now
that we build a `DependentScopeDeclRefExpr` for `T::x`, it is
incorrectly transformed as if it was the operand of the address of
operator and we fail to diagnose the invalid reference to a non-static
data member. This patch fixes the issue by only calling
`TreeTransform::TransformAddressOfOperand` for `CXXOperatorCallExpr`s
with a single operand. This fixes #97483.

Added: 
    clang/test/CXX/expr/expr.prim/expr.prim.id/expr.prim.id.general/p4.cpp

Modified: 
    clang/docs/ReleaseNotes.rst
    clang/lib/Sema/TreeTransform.h

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index f40fd1cd145bb..f149684214567 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -954,6 +954,8 @@ Bug Fixes to C++ Support
   forward-declared class. (#GH93512).
 - Fixed a bug in access checking inside return-type-requirement of compound requirements. (#GH93788).
 - Fixed an assertion failure about invalid conversion when calling lambda. (#GH96205).
+- Fixed a bug where the first operand of binary ``operator&`` would be transformed as if it was the operand
+  of the address of operator. (#GH97483).
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^

diff  --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 51ba22f99e3a3..4450ebaf615cd 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -12919,7 +12919,7 @@ TreeTransform<Derived>::TransformCXXOperatorCallExpr(CXXOperatorCallExpr *E) {
   }
 
   ExprResult First;
-  if (E->getOperator() == OO_Amp)
+  if (E->getNumArgs() == 1 && E->getOperator() == OO_Amp)
     First = getDerived().TransformAddressOfOperand(E->getArg(0));
   else
     First = getDerived().TransformExpr(E->getArg(0));

diff  --git a/clang/test/CXX/expr/expr.prim/expr.prim.id/expr.prim.id.general/p4.cpp b/clang/test/CXX/expr/expr.prim/expr.prim.id/expr.prim.id.general/p4.cpp
new file mode 100644
index 0000000000000..e6d9c171e3893
--- /dev/null
+++ b/clang/test/CXX/expr/expr.prim/expr.prim.id/expr.prim.id.general/p4.cpp
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -verify %s
+
+struct A {
+  int x;
+};
+
+void operator&(A, A);
+
+template<typename T>
+struct B {
+  int f() {
+    return T::x & 1; // expected-error {{invalid use of non-static data member 'x'}}
+  }
+};
+
+template struct B<A>; // expected-note {{in instantiation of}}