Fix crash on zero-argument assignment operator.

Make sure we don't crash when checking whether an assignment operator
without any arguments is a special member.  <rdar://problem/14397774>.

llvm-svn: 186137

clang/lib/AST/DeclCXX.cpp

@@ -1406,7 +1406,8 @@ bool CXXMethodDecl::isCopyAssignmentOperator() const {
   //  type X, X&, const X&, volatile X& or const volatile X&.
   if (/*operator=*/getOverloadedOperator() != OO_Equal ||
       /*non-static*/ isStatic() || 
-      /*non-template*/getPrimaryTemplate() || getDescribedFunctionTemplate())
+      /*non-template*/getPrimaryTemplate() || getDescribedFunctionTemplate() ||
+      getNumParams() != 1)
     return false;
       
   QualType ParamType = getParamDecl(0)->getType();
@@ -1425,7 +1426,8 @@ bool CXXMethodDecl::isMoveAssignmentOperator() const {
   //  non-template member function of class X with exactly one parameter of type
   //  X&&, const X&&, volatile X&&, or const volatile X&&.
   if (getOverloadedOperator() != OO_Equal || isStatic() ||
-      getPrimaryTemplate() || getDescribedFunctionTemplate())
+      getPrimaryTemplate() || getDescribedFunctionTemplate() ||
+      getNumParams() != 1)
     return false;
 
   QualType ParamType = getParamDecl(0)->getType();

clang/lib/Sema/SemaDeclCXX.cpp

@@ -11535,6 +11535,7 @@ void Sema::SetDeclDefaulted(Decl *Dcl, SourceLocation DefaultLoc) {
 
     CXXSpecialMember Member = getSpecialMember(MD);
     if (Member == CXXInvalid) {
+      if (!MD->isInvalidDecl())
         Diag(DefaultLoc, diag::err_default_special_members);
       return;
     }

clang/test/SemaCXX/overloaded-operator.cpp

@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s 
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s 
 class X { };
 
 X operator+(X, X);
@@ -441,3 +441,7 @@ namespace test10 {
     a[bar<float>];
   }
 }
+
+struct InvalidOperatorEquals {
+  InvalidOperatorEquals operator=() = delete; // expected-error {{overloaded 'operator=' must be a binary operator}}
+};