Sema: Implement DR244

Summary:
Naming the destructor using a typedef-name for the class-name is
well-formed.

This fixes PR19620.

Reviewers: rsmith, doug.gregor

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D3583

llvm-svn: 209319

clang/lib/Sema/SemaExprCXX.cpp

@@ -121,31 +121,26 @@ ParsedType Sema::getDestructorName(SourceLocation TildeLoc,
 
     bool AlreadySearched = false;
     bool LookAtPrefix = true;
-    // C++ [basic.lookup.qual]p6:
+    // C++11 [basic.lookup.qual]p6:
     //   If a pseudo-destructor-name (5.2.4) contains a nested-name-specifier,
     //   the type-names are looked up as types in the scope designated by the
-    //   nested-name-specifier. In a qualified-id of the form:
+    //   nested-name-specifier. Similarly, in a qualified-id of the form:
     //
-    //     ::[opt] nested-name-specifier  ~ class-name
+    //     nested-name-specifier[opt] class-name :: ~ class-name
     //
-    //   where the nested-name-specifier designates a namespace scope, and in
-    //   a qualified-id of the form:
+    //   the second class-name is looked up in the same scope as the first.
     //
-    //     ::opt nested-name-specifier class-name ::  ~ class-name
-    //
-    //   the class-names are looked up as types in the scope designated by
-    //   the nested-name-specifier.
-    //
-    // Here, we check the first case (completely) and determine whether the
-    // code below is permitted to look at the prefix of the
-    // nested-name-specifier.
+    // Here, we determine whether the code below is permitted to look at the
+    // prefix of the nested-name-specifier.
     DeclContext *DC = computeDeclContext(SS, EnteringContext);
     if (DC && DC->isFileContext()) {
       AlreadySearched = true;
       LookupCtx = DC;
       isDependent = false;
-    } else if (DC && isa<CXXRecordDecl>(DC))
+    } else if (DC && isa<CXXRecordDecl>(DC)) {
       LookAtPrefix = false;
+      LookInScope = true;
+    }
 
     // The second case from the C++03 rules quoted further above.
     NestedNameSpecifier *Prefix = 0;
@@ -163,8 +158,6 @@ ParsedType Sema::getDestructorName(SourceLocation TildeLoc,
       LookupCtx = computeDeclContext(SS, EnteringContext);
       isDependent = LookupCtx && LookupCtx->isDependentContext();
     }
-
-    LookInScope = false;
   } else if (ObjectTypePtr) {
     // C++ [basic.lookup.classref]p3:
     //   If the unqualified-id is ~type-name, the type-name is looked up

clang/test/CXX/basic/basic.lookup/basic.lookup.qual/p6.cpp

@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -fsyntax-only -verify %s
+// expected-no-diagnostics
 
 struct C { 
   typedef int I;
@@ -20,5 +21,5 @@ struct A {
 typedef A AB; 
 int main() {
   AB *p; 
-  p->AB::~AB(); // expected-error{{expected the class name after '~' to name a destructor}}
+  p->AB::~AB();
 }

clang/test/CXX/drs/dr2xx.cpp

@@ -466,7 +466,7 @@ namespace dr243 { // dr243: yes
   A a2 = b; // expected-error {{ambiguous}}
 }
 
-namespace dr244 { // dr244: no
+namespace dr244 { // dr244: 3.5
   struct B {}; struct D : B {}; // expected-note {{here}}
 
   D D_object;
@@ -480,7 +480,7 @@ namespace dr244 { // dr244: no
     B_ptr->~B_alias();
     B_ptr->B_alias::~B();
     // This is valid under DR244.
-    B_ptr->B_alias::~B_alias(); // FIXME: expected-error {{expected the class name after '~' to name a destructor}}
+    B_ptr->B_alias::~B_alias();
     B_ptr->dr244::~B(); // expected-error {{refers to a member in namespace}}
     B_ptr->dr244::~B_alias(); // expected-error {{refers to a member in namespace}}
   }
@@ -1013,11 +1013,16 @@ namespace dr298 { // dr298: yes
 
   B::B() {} // expected-error {{requires a type specifier}}
   B::A() {} // ok
-  C::~C() {} // expected-error {{expected the class name}}
-  C::~A() {} // ok
+  C::~C() {} // expected-error {{destructor cannot be declared using a typedef 'C' (aka 'const dr298::A') of the class name}}
 
   typedef struct D E; // expected-note {{here}}
   struct E {}; // expected-error {{conflicts with typedef}}
+
+  struct F {
+    ~F();
+  };
+  typedef const F G;
+  G::~F() {} // ok
 }
 
 namespace dr299 { // dr299: yes c++11

clang/www/cxx_dr_status.html

@@ -1504,7 +1504,7 @@ accessible?</td>
     <td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#244">244</a></td>
     <td>CD1</td>
     <td>Destructor lookup</td>
-    <td class="none" align="center">No</td>
+    <td class="svn" align="center">SVN</td>
   </tr>
   <tr id="245">
     <td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#245">245</a></td>