[clang] 3466cdb - [clang][CodeComplete] skip explicit obj param when creating signature string (#146649)

via cfe-commits cfe-commits at lists.llvm.org
Wed Jul 30 23:12:28 PDT 2025


Author: Mythreya Kuricheti
Date: 2025-07-31T02:12:25-04:00
New Revision: 3466cdb76944022d17a45fa66edd275bcd3a68d1

URL: https://github.com/llvm/llvm-project/commit/3466cdb76944022d17a45fa66edd275bcd3a68d1
DIFF: https://github.com/llvm/llvm-project/commit/3466cdb76944022d17a45fa66edd275bcd3a68d1.diff

LOG: [clang][CodeComplete] skip explicit obj param when creating signature string (#146649)

Fixes clangd/clangd#2284

Added: 
    

Modified: 
    clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
    clang/lib/Sema/SemaCodeComplete.cpp
    clang/test/CodeCompletion/skip-explicit-object-parameter.cpp

Removed: 
    


################################################################################
diff  --git a/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp b/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
index 5a5d815076e2a..61bd6318b46cf 100644
--- a/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
+++ b/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
@@ -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("([[auto&&]], [[int]]) ->
+    // void")));
+  }
+}
+
 TEST(CompletionTest, IncludedCompletionKinds) {
   Annotations Test(R"cpp(#include "^)cpp");
   auto TU = TestTU::withCode(Test.code());
@@ -4369,14 +4419,24 @@ TEST(CompletionTest, 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.^
+      a.$c1^;
+      (&A::fo$c2^;
+      (&A::ba$c3^;
     }
   )cpp");
 
+  // TODO: llvm/llvm-project/146649
+  // This is incorrect behavior. Correct Result should be a variant of,
+  // c2: signature = (auto&& self, int arg)
+  //     snippet = (${1: auto&& self}, ${2: int arg})
+  // c3: signature = (A self, int arg)
+  //     snippet = (${1: A self}, ${2: int arg})
+
   auto TU = TestTU::withCode(Code.code());
   TU.ExtraArgs = {"-std=c++23"};
 
@@ -4387,12 +4447,31 @@ TEST(CompletionTest, SkipExplicitObjectParameter) {
 
   MockFS FS;
   auto Inputs = TU.inputs(FS);
-  auto Result = codeComplete(testPath(TU.Filename), Code.point(),
-                             Preamble.get(), Inputs, Opts);
-
-  EXPECT_THAT(Result.Completions,
-              ElementsAre(AllOf(named("foo"), signature("(int arg)"),
-                                snippetSuffix("(${1:int arg})"))));
+  {
+    auto Result = codeComplete(testPath(TU.Filename), Code.point("c1"),
+                               Preamble.get(), Inputs, Opts);
+
+    EXPECT_THAT(Result.Completions,
+                UnorderedElementsAre(AllOf(named("foo"), signature("(int arg)"),
+                                           snippetSuffix("(${1:int arg})")),
+                                     AllOf(named("bar"), signature("(int arg)"),
+                                           snippetSuffix("(${1:int arg})"))));
+  }
+  {
+    auto Result = codeComplete(testPath(TU.Filename), Code.point("c2"),
+                               Preamble.get(), Inputs, Opts);
+    EXPECT_THAT(
+        Result.Completions,
+        ElementsAre(AllOf(named("foo"), signature("<class self:auto>(int arg)"),
+                          snippetSuffix("<${1:class self:auto}>"))));
+  }
+  {
+    auto Result = codeComplete(testPath(TU.Filename), Code.point("c3"),
+                               Preamble.get(), Inputs, Opts);
+    EXPECT_THAT(Result.Completions,
+                ElementsAre(AllOf(named("bar"), signature("(int arg)"),
+                                  snippetSuffix(""))));
+  }
 }
 } // namespace
 } // namespace clangd

diff  --git a/clang/lib/Sema/SemaCodeComplete.cpp b/clang/lib/Sema/SemaCodeComplete.cpp
index a43ac9eb7610d..0de55800ccdd1 100644
--- a/clang/lib/Sema/SemaCodeComplete.cpp
+++ b/clang/lib/Sema/SemaCodeComplete.cpp
@@ -4034,6 +4034,14 @@ static void AddOverloadParameterChunks(
       return;
     }
 
+    // C++23 introduces an explicit object parameter, a.k.a. "deducing this"
+    // Skip it for autocomplete and treat the next parameter as the first
+    // parameter
+    if (Function && FirstParameter &&
+        Function->getParamDecl(P)->isExplicitObjectParameter()) {
+      continue;
+    }
+
     if (FirstParameter)
       FirstParameter = false;
     else

diff  --git a/clang/test/CodeCompletion/skip-explicit-object-parameter.cpp b/clang/test/CodeCompletion/skip-explicit-object-parameter.cpp
index 55c16bb126fee..587d6cb044d19 100644
--- a/clang/test/CodeCompletion/skip-explicit-object-parameter.cpp
+++ b/clang/test/CodeCompletion/skip-explicit-object-parameter.cpp
@@ -1,14 +1,48 @@
 struct A {
-  void foo(this A self, int arg);
+  void foo(this auto&& self, int arg);
+  void bar(this A self, int arg);
 };
 
-int main() {
+int func1() {
   A a {};
   a.
 }
-// RUN: %clang_cc1 -cc1 -fsyntax-only -code-completion-at=%s:%(line-2):5 -std=c++23 %s | FileCheck %s
-// CHECK: COMPLETION: A : A::
-// CHECK-NEXT: COMPLETION: foo : [#void#]foo(<#int arg#>)
-// CHECK-NEXT: COMPLETION: operator= : [#A &#]operator=(<#const A &#>)
-// CHECK-NEXT: COMPLETION: operator= : [#A &#]operator=(<#A &&#>)
-// CHECK-NEXT: COMPLETION: ~A : [#void#]~A()
+// RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:%(line-2):5 -std=c++23 %s | FileCheck -check-prefix=CHECK-CC1 %s
+// CHECK-CC1: COMPLETION: A : A::
+// CHECK-NEXT-CC1: COMPLETION: bar : [#void#]bar(<#int arg#>)
+// CHECK-NEXT-CC1: COMPLETION: foo : [#void#]foo(<#int arg#>)
+// CHECK-NEXT-CC1: COMPLETION: operator= : [#A &#]operator=(<#const A &#>)
+// CHECK-NEXT-CC1: COMPLETION: operator= : [#A &#]operator=(<#A &&#>)
+// CHECK-NEXT-CC1: COMPLETION: ~A : [#void#]~A()
+
+struct B {
+  template <typename T>
+  void foo(this T&& self, int arg);
+};
+
+int func2() {
+  B b {};
+  b.foo();
+}
+// RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:%(line-2):9 -std=c++23 %s | FileCheck -check-prefix=CHECK-CC2 %s
+// CHECK-CC2: OVERLOAD: [#void#]foo(int arg)
+
+// TODO: llvm/llvm-project/146649
+// This is incorrect behavior. Correct Result should be a variant of, 
+// CC3: should be something like [#void#]foo(<#A self#>, <#int arg#>)
+// CC4: should be something like [#void#]bar(<#A self#>, <#int arg#>)
+int func3() {
+  (&A::foo)
+  (&A::bar)
+}
+// RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:%(line-3):10 -std=c++23 %s | FileCheck -check-prefix=CHECK-CC3 %s
+// CHECK-CC3: COMPLETION: foo : [#void#]foo<<#class self:auto#>>(<#int arg#>)
+// RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:%(line-4):10 -std=c++23 %s | FileCheck -check-prefix=CHECK-CC4 %s
+// CHECK-CC4: COMPLETION: bar : [#void#]bar(<#int arg#>)
+
+int func4() {
+  // TODO (&A::foo)(
+  (&A::bar)(
+}
+// RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:%(line-2):13 -std=c++23 %s | FileCheck -check-prefix=CHECK-CC5 %s
+// CHECK-CC5: OVERLOAD: [#void#](<#A#>, int)


        


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