Correctly demangle the <unresolved-name> at the end of dt and pt (x.y, x->y).

PiperOrigin-RevId: 637934582
Change-Id: Ie89b4317b11adba058dd999800e514eff49d4d69

absl/debugging/internal/demangle.cc

@@ -1956,8 +1956,10 @@ static bool ParseExpression(State *state) {
   state->parse_state = copy;
 
   // Object and pointer member access expressions.
+  //
+  // <expression> ::= (dt | pt) <expression> <unresolved-name>
   if ((ParseTwoCharToken(state, "dt") || ParseTwoCharToken(state, "pt")) &&
-      ParseExpression(state) && ParseType(state)) {
+      ParseExpression(state) && ParseUnresolvedName(state)) {
     return true;
   }
   state->parse_state = copy;

absl/debugging/internal/demangle_test.cc

@@ -407,6 +407,14 @@ TEST(Demangle, ThisPointerInDependentSignature) {
   EXPECT_STREQ("S::f<>()", tmp);
 }
 
+TEST(Demangle, DependentMemberOperatorCall) {
+  char tmp[80];
+
+  // decltype(fp.operator()()) f<C>(C)
+  EXPECT_TRUE(Demangle("_Z1fI1CEDTcldtfp_onclEET_", tmp, sizeof(tmp)));
+  EXPECT_STREQ("f<>()", tmp);
+}
+
 // Test subobject-address template parameters.
 TEST(Demangle, SubobjectAddresses) {
   char tmp[80];