[clang] [clang-tools-extra] [clang][CodeComplete] skip explicit obj param in SignatureHelp (PR #146649)

[Nathan Ridge via cfe-commits]

================
@@ -3267,6 +3267,56 @@ TEST(SignatureHelpTest, VariadicType) {
   }
 }
 
+TEST(SignatureHelpTest, SkipExplicitObjectParameter) {
+  Annotations Code(R"cpp(
+    struct A {
+      void foo(this auto&& self, int arg); 
+      void bar(this A self, int arg);
+    };
+    int main() {
+      A a {};
+      a.foo($c1^);
+      (&A::bar)($c2^);
+      (&A::foo)($c3^);
+    }
+  )cpp");
+
+  auto TU = TestTU::withCode(Code.code());
+  TU.ExtraArgs = {"-std=c++23"};
+
+  MockFS FS;
+  auto Inputs = TU.inputs(FS);
+
+  auto Preamble = TU.preamble();
+  ASSERT_TRUE(Preamble);
+
+  {
+    const auto Result = signatureHelp(testPath(TU.Filename), Code.point("c1"),
+                                      *Preamble, Inputs, MarkupKind::PlainText);
+
+    EXPECT_EQ(1U, Result.signatures.size());
+
+    EXPECT_THAT(Result.signatures[0], AllOf(sig("foo([[int arg]]) -> void")));
+  }
+  {
+    const auto Result = signatureHelp(testPath(TU.Filename), Code.point("c2"),
+                                      *Preamble, Inputs, MarkupKind::PlainText);
+
+    EXPECT_EQ(1U, Result.signatures.size());
+
+    EXPECT_THAT(Result.signatures[0], AllOf(sig("([[A]], [[int]]) -> void")));
+  }
+  {
+    // TODO: llvm/llvm-project/146649
+    const auto Result = signatureHelp(testPath(TU.Filename), Code.point("c3"),
+                                      *Preamble, Inputs, MarkupKind::PlainText);
+    // TODO: We expect 1 signature here, with this signature
+    EXPECT_EQ(0U, Result.signatures.size());
+    // EXPECT_THAT(Result.signatures[0], AllOf(sig("([[A&&]], [[int]]) ->
----------------
HighCommander4 wrote:

nit: `auto&&` rather than `A&&`, I believe

https://github.com/llvm/llvm-project/pull/146649