[ASTMatchers] Fix matching CXXOperatorCallExpr of -> (#139994)

The `->` operator does not have a corresponding `UnaryOperatorKind`, and
so was unsupported by the `hasOperatorName` and `hasUnaryOperand`
matchers.

Instead of trying to determine the equivalent unary or binary operator
and then deriving the opcode string, we consult `OperatorKinds.def`
directly (through `getOperatorSpelling`).

For `hasUnaryOperand` support, we special case the arrow operator
specifically.

Author: tJener

clang/include/clang/ASTMatchers/ASTMatchersInternal.h

@@ -2161,8 +2161,10 @@ inline const Expr *getSubExpr(const NodeType &Node) {
 template <>
 inline const Expr *
 getSubExpr<CXXOperatorCallExpr>(const CXXOperatorCallExpr &Node) {
-  if (!internal::equivalentUnaryOperator(Node))
+  if (!internal::equivalentUnaryOperator(Node) &&
+      Node.getOperator() != OO_Arrow) {
     return nullptr;
+  }
   return Node.getArg(0);
 }
 
@@ -2223,14 +2225,9 @@ inline StringRef getOpName(const CXXRewrittenBinaryOperator &Node) {
   return Node.getOpcodeStr();
 }
 inline std::optional<StringRef> getOpName(const CXXOperatorCallExpr &Node) {
-  auto optBinaryOpcode = equivalentBinaryOperator(Node);
-  if (!optBinaryOpcode) {
-    auto optUnaryOpcode = equivalentUnaryOperator(Node);
-    if (!optUnaryOpcode)
-      return std::nullopt;
-    return UnaryOperator::getOpcodeStr(*optUnaryOpcode);
-  }
-  return BinaryOperator::getOpcodeStr(*optBinaryOpcode);
+  if (const char *Str = getOperatorSpelling(Node.getOperator()))
+    return Str;
+  return std::nullopt;
 }
 inline StringRef getOpName(const CXXFoldExpr &Node) {
   return BinaryOperator::getOpcodeStr(Node.getOperator());
@@ -2271,14 +2268,9 @@ class HasAnyOperatorNameMatcher : public SingleNodeMatcherInterface<T> {
     return Node.getOpcodeStr();
   }
   static std::optional<StringRef> getOpName(const CXXOperatorCallExpr &Node) {
-    auto optBinaryOpcode = equivalentBinaryOperator(Node);
-    if (!optBinaryOpcode) {
-      auto optUnaryOpcode = equivalentUnaryOperator(Node);
-      if (!optUnaryOpcode)
-        return std::nullopt;
-      return UnaryOperator::getOpcodeStr(*optUnaryOpcode);
-    }
-    return BinaryOperator::getOpcodeStr(*optBinaryOpcode);
+    if (const char *Str = getOperatorSpelling(Node.getOperator()))
+      return Str;
+    return std::nullopt;
   }
 
   std::vector<std::string> Names;

clang/unittests/ASTMatchers/ASTMatchersTraversalTest.cpp

@@ -2025,21 +2025,36 @@ void plusIntOperator()
                          hasOperatorName("+"), hasUnaryOperand(expr())))));
 
   Code = R"cpp(
-struct HasOpArrow
+struct S {
+  void foo(int);
+};
+struct HasOpStar
 {
     int& operator*();
 };
-void foo()
+struct HasOpArrow
 {
-    HasOpArrow s1;
-    *s1;
+    S* operator->();
+};
+void hasOpStarMem(HasOpStar s)
+{
+    *s;
+}
+void hasOpArrowMem(HasOpArrow a)
+{
+    a->foo(42);
 }
 )cpp";
 
   EXPECT_TRUE(
       matches(Code, traverse(TK_IgnoreUnlessSpelledInSource,
                              cxxOperatorCallExpr(hasOperatorName("*"),
                                                  hasUnaryOperand(expr())))));
+  EXPECT_TRUE(matches(
+      Code, traverse(TK_IgnoreUnlessSpelledInSource,
+                     cxxOperatorCallExpr(hasOperatorName("->"),
+                                         hasUnaryOperand(declRefExpr(
+                                             to(varDecl(hasName("a")))))))));
 }
 
 TEST(Matcher, UnaryOperatorTypes) {