[AST] Fix structural inequivalence of operators

[martong]

Summary

Operators kind was not checked, so we reported e.g. op- to be equal with op+

[a_sidorin]

Looks good, thanks!

[shafik]

unittests/AST/StructuralEquivalenceTest.cpp

251

Curious, is this test just for completeness or is this somehow related to the overloaded operator check?

[martong]

unittests/AST/StructuralEquivalenceTest.cpp

251

This is just for the sake of completeness. Operators and ctor/dtor do not have regular names with IdentifierInfo. (See the DeclarationName class for details.)

lib/AST/ASTStructuralEquivalence.cpp

if (auto *MD2 = dyn_cast<CXXMethodDecl>(D2)) {
       if (!::IsStructurallyEquivalent(*this, MD1, MD2))
         return false;
     } else {
       // Kind mismatch.
       return false;
     }
   } else if (FunctionDecl *FD1 = dyn_cast<FunctionDecl>(D1)) {
     if (FunctionDecl *FD2 = dyn_cast<FunctionDecl>(D2)) {
+      if (FD1->isOverloadedOperator()) {
+        if (!FD2->isOverloadedOperator())
+          return false;
+        if (FD1->getOverloadedOperator() != FD2->getOverloadedOperator())
+          return false;
+      }
       if (!::IsStructurallyEquivalent(FD1->getIdentifier(),
                                       FD2->getIdentifier()))
         return false;
       if (!::IsStructurallyEquivalent(*this, FD1, FD2))
         return false;
     } else {
       // Kind mismatch.
       return false;

unittests/AST/StructuralEquivalenceTest.cpp

 TEST_F(StructuralEquivalenceFunctionTest, TemplateVsNonTemplate) {
   auto t = makeNamedDecls(
       "void foo();",
       "template<class T> void foo();",
       Lang_CXX);
   EXPECT_FALSE(testStructuralMatch(t));
 }
 
+TEST_F(StructuralEquivalenceFunctionTest, DifferentOperators) {
+  auto t = makeDecls<FunctionDecl>(
+      "struct X{}; bool operator<(X, X);",
+      "struct X{}; bool operator==(X, X);", Lang_CXX,
+      functionDecl(hasOverloadedOperatorName("<")),
+      functionDecl(hasOverloadedOperatorName("==")));
+  EXPECT_FALSE(testStructuralMatch(t));
+}
+
+TEST_F(StructuralEquivalenceFunctionTest, SameOperators) {
+  auto t = makeDecls<FunctionDecl>(
+      "struct X{}; bool operator<(X, X);",
+      "struct X{}; bool operator<(X, X);", Lang_CXX,
+      functionDecl(hasOverloadedOperatorName("<")),
+      functionDecl(hasOverloadedOperatorName("<")));
+  EXPECT_TRUE(testStructuralMatch(t));
+}
+
+TEST_F(StructuralEquivalenceFunctionTest, CtorVsDtor) {
+  auto t = makeDecls<FunctionDecl>(
+      "struct X{ X(); };",
+      "struct X{ ~X(); };", Lang_CXX,
+      cxxConstructorDecl(),
+      cxxDestructorDecl());
+  EXPECT_FALSE(testStructuralMatch(t));
+}
+
 TEST_F(StructuralEquivalenceFunctionTest, ParamConstWithRef) {
   auto t = makeNamedDecls("void foo(int&);",
                           "void foo(const int&);", Lang_CXX);
   EXPECT_FALSE(testStructuralMatch(t));
 }
 
 TEST_F(StructuralEquivalenceFunctionTest, ParamConstSimple) {
   auto t = makeNamedDecls("void foo(int);",