[PATCH] D35297: [Sema] Fix operator lookup to consider local extern declarations.

[Eric Fiselier via Phabricator via cfe-commits]

EricWF created this revision.

Previously Clang was not considering operator declarations that occur at function scope. This is incorrect according to [over.match.oper]p3

> The set of non-member candidates is the result of the unqualified lookup of operator@ in the context of the expression according to the usual rules for name lookup in unqualified function calls.

This patch fixes operator name lookup to consider block scope declarations.

I think there might be existing open bugs for this but I can't find them.


https://reviews.llvm.org/D35297

Files:
  lib/Sema/SemaLookup.cpp
  test/CXX/over/over.match/over.match.funcs/over.match.oper/p3.cpp


Index: test/CXX/over/over.match/over.match.funcs/over.match.oper/p3.cpp
===================================================================
--- test/CXX/over/over.match/over.match.funcs/over.match.oper/p3.cpp
+++ test/CXX/over/over.match/over.match.funcs/over.match.oper/p3.cpp
@@ -2,6 +2,21 @@
 
 namespace bullet2 {
 
+// The set of non-member candidates is the result of the unqualified lookup of
+// operator@ in the context of the expression according to the usual rules for
+// name lookup in unqualified function calls.
+
+// Test that local extern declarations are allowed.
+struct A {};
+void test_local_lookup() {
+  A a;
+  +a; // expected-error {{invalid argument type 'bullet2::A' to unary expression}}
+  a + a; // expected-error {{invalid operands to binary expression ('bullet2::A' and 'bullet2::A')}}
+  void operator+(A);
+  void operator+(A, A);
+  +a; // OK
+  a + a;
+}
 // For non-member candidates, if no operand has a class type, only those
 // non-member functions that have a matching enumeration parameter are
 // candidates.
Index: lib/Sema/SemaLookup.cpp
===================================================================
--- lib/Sema/SemaLookup.cpp
+++ lib/Sema/SemaLookup.cpp
@@ -226,7 +226,7 @@
     // Operator lookup is its own crazy thing;  it is not the same
     // as (e.g.) looking up an operator name for redeclaration.
     assert(!Redeclaration && "cannot do redeclaration operator lookup");
-    IDNS = Decl::IDNS_NonMemberOperator;
+    IDNS = Decl::IDNS_NonMemberOperator | Decl::IDNS_LocalExtern;
     break;
 
   case Sema::LookupTagName:


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