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merged 5 commits into from
Aug 21, 2025
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[clang] Include explicit object methods in overload suggestions #154041

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471fa8c
[clang] Include explicit object methods in overload suggestions
MythreyaK Aug 16, 2025
aa2c6fe
Add const to signature string
MythreyaK Aug 18, 2025
639da07
Update tests
MythreyaK Aug 18, 2025
d2476ed
code review
MythreyaK Aug 20, 2025
888ef93
code review
MythreyaK Aug 21, 2025
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133 changes: 133 additions & 0 deletions clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4532,6 +4532,139 @@ TEST(CompletionTest, MemberAccessInExplicitObjMemfn) {
EXPECT_THAT(Result.Completions, ElementsAre());
}
}

TEST(CompletionTest, ListExplicitObjectOverloads) {
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Test slightly modified from example that @zwuis originally shared in the ticket.

Happy to change or update!

Annotations Code(R"cpp(
struct S {
void foo1(int a);
void foo2(int a) const;
void foo2(this const S& self, float a);
void foo3(this const S& self, int a);
void foo4(this S& self, int a);
};

void S::foo1(int a) {
this->$c1^;
}

void S::foo2(int a) const {
this->$c2^;
}

void S::foo3(this const S& self, int a) {
self.$c3^;
}

void S::foo4(this S& self, int a) {
self.$c4^;
}

void test1(S s) {
s.$c5^;
}

void test2(const S s) {
s.$c6^;
}
)cpp");

auto TU = TestTU::withCode(Code.code());
TU.ExtraArgs = {"-std=c++23"};

auto Preamble = TU.preamble();
ASSERT_TRUE(Preamble);

CodeCompleteOptions Opts{};

MockFS FS;
auto Inputs = TU.inputs(FS);

{
auto Result = codeComplete(testPath(TU.Filename), Code.point("c1"),
Preamble.get(), Inputs, Opts);
EXPECT_THAT(
Result.Completions,
UnorderedElementsAre(AllOf(named("foo1"), signature("(int a)"),
snippetSuffix("(${1:int a})")),
AllOf(named("foo2"), signature("(int a) const"),
snippetSuffix("(${1:int a})")),
AllOf(named("foo2"), signature("(float a) const"),
snippetSuffix("(${1:float a})")),
AllOf(named("foo3"), signature("(int a) const"),
snippetSuffix("(${1:int a})")),
AllOf(named("foo4"), signature("(int a)"),
snippetSuffix("(${1:int a})"))));
}
{
auto Result = codeComplete(testPath(TU.Filename), Code.point("c2"),
Preamble.get(), Inputs, Opts);
EXPECT_THAT(
Result.Completions,
UnorderedElementsAre(AllOf(named("foo2"), signature("(int a) const"),
snippetSuffix("(${1:int a})")),
AllOf(named("foo2"), signature("(float a) const"),
snippetSuffix("(${1:float a})")),
AllOf(named("foo3"), signature("(int a) const"),
snippetSuffix("(${1:int a})"))));
}
{
auto Result = codeComplete(testPath(TU.Filename), Code.point("c3"),
Preamble.get(), Inputs, Opts);
EXPECT_THAT(
Result.Completions,
UnorderedElementsAre(AllOf(named("foo2"), signature("(int a) const"),
snippetSuffix("(${1:int a})")),
AllOf(named("foo2"), signature("(float a) const"),
snippetSuffix("(${1:float a})")),
AllOf(named("foo3"), signature("(int a) const"),
snippetSuffix("(${1:int a})"))));
}
{
auto Result = codeComplete(testPath(TU.Filename), Code.point("c4"),
Preamble.get(), Inputs, Opts);
EXPECT_THAT(
Result.Completions,
UnorderedElementsAre(AllOf(named("foo1"), signature("(int a)"),
snippetSuffix("(${1:int a})")),
AllOf(named("foo2"), signature("(int a) const"),
snippetSuffix("(${1:int a})")),
AllOf(named("foo2"), signature("(float a) const"),
snippetSuffix("(${1:float a})")),
AllOf(named("foo3"), signature("(int a) const"),
snippetSuffix("(${1:int a})")),
AllOf(named("foo4"), signature("(int a)"),
snippetSuffix("(${1:int a})"))));
}
{
auto Result = codeComplete(testPath(TU.Filename), Code.point("c5"),
Preamble.get(), Inputs, Opts);
EXPECT_THAT(
Result.Completions,
UnorderedElementsAre(AllOf(named("foo1"), signature("(int a)"),
snippetSuffix("(${1:int a})")),
AllOf(named("foo2"), signature("(int a) const"),
snippetSuffix("(${1:int a})")),
AllOf(named("foo2"), signature("(float a) const"),
snippetSuffix("(${1:float a})")),
AllOf(named("foo3"), signature("(int a) const"),
snippetSuffix("(${1:int a})")),
AllOf(named("foo4"), signature("(int a)"),
snippetSuffix("(${1:int a})"))));
}
{
auto Result = codeComplete(testPath(TU.Filename), Code.point("c6"),
Preamble.get(), Inputs, Opts);
EXPECT_THAT(
Result.Completions,
UnorderedElementsAre(AllOf(named("foo2"), signature("(int a) const"),
snippetSuffix("(${1:int a})")),
AllOf(named("foo2"), signature("(float a) const"),
snippetSuffix("(${1:float a})")),
AllOf(named("foo3"), signature("(int a) const"),
snippetSuffix("(${1:int a})"))));
}
}

} // namespace
} // namespace clangd
} // namespace clang
95 changes: 65 additions & 30 deletions clang/lib/Sema/SemaCodeComplete.cpp
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Expand Up @@ -413,6 +413,37 @@ class ResultBuilder {
bool IsImpossibleToSatisfy(const NamedDecl *ND) const;
//@}
};

void AddFunctionTypeQuals(CodeCompletionBuilder &Result,
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nit: can we move this closer to where it's used? (we can make it static if needed)

const Qualifiers Quals) {
// FIXME: Add ref-qualifier!

// Handle single qualifiers without copying
if (Quals.hasOnlyConst()) {
Result.AddInformativeChunk(" const");
return;
}

if (Quals.hasOnlyVolatile()) {
Result.AddInformativeChunk(" volatile");
return;
}

if (Quals.hasOnlyRestrict()) {
Result.AddInformativeChunk(" restrict");
return;
}

// Handle multiple qualifiers.
std::string QualsStr;
if (Quals.hasConst())
QualsStr += " const";
if (Quals.hasVolatile())
QualsStr += " volatile";
if (Quals.hasRestrict())
QualsStr += " restrict";
Result.AddInformativeChunk(Result.getAllocator().CopyString(QualsStr));
}
} // namespace

void PreferredTypeBuilder::enterReturn(Sema &S, SourceLocation Tok) {
Expand Down Expand Up @@ -1435,6 +1466,14 @@ void ResultBuilder::AddResult(Result R, DeclContext *CurContext,

AdjustResultPriorityForDecl(R);

// Account for explicit object parameter
const auto GetQualifiers = [&](const CXXMethodDecl *MethodDecl) {
if (MethodDecl->isExplicitObjectMemberFunction())
return MethodDecl->getFunctionObjectParameterType().getQualifiers();
else
return MethodDecl->getMethodQualifiers();
};

if (IsExplicitObjectMemberFunction &&
R.Kind == CodeCompletionResult::RK_Declaration &&
(isa<CXXMethodDecl>(R.Declaration) || isa<FieldDecl>(R.Declaration))) {
Expand All @@ -1447,7 +1486,7 @@ void ResultBuilder::AddResult(Result R, DeclContext *CurContext,
if (HasObjectTypeQualifiers)
if (const auto *Method = dyn_cast<CXXMethodDecl>(R.Declaration))
if (Method->isInstance()) {
Qualifiers MethodQuals = Method->getMethodQualifiers();
Qualifiers MethodQuals = GetQualifiers(Method);
if (ObjectTypeQualifiers == MethodQuals)
R.Priority += CCD_ObjectQualifierMatch;
else if (ObjectTypeQualifiers - MethodQuals) {
Expand Down Expand Up @@ -3426,40 +3465,36 @@ static void AddQualifierToCompletionString(CodeCompletionBuilder &Result,
Result.AddTextChunk(Result.getAllocator().CopyString(PrintedNNS));
}

static void
AddFunctionTypeQualsToCompletionString(CodeCompletionBuilder &Result,
const FunctionDecl *Function) {
const auto *Proto = Function->getType()->getAs<FunctionProtoType>();
if (!Proto || !Proto->getMethodQuals())
return;
// Sets the function qualifiers completion string by inspecting the explicit
// object
static void AddCXXExplicitObjectFunctionTypeQualsToCompletionString(
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This is a nice touch!

One minor comment: could we refactor this to reuse code between this function, and the rest of AddFunctionTypeQualsToCompletionString? (That way, the "Handle single qualifiers without copying" optimization would apply here as well.)

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After the refactor for code-reuse, it feels like the body of AddCXXExplicitObjectFunctionTypeQualsToCompletionString can be moved back into AddFunctionTypeQualsToCompletionString, to make it similar to the code in else branch.

I think either is fine, leaving this as is or moving the body back into AddFunctionTypeQualsToCompletionString, let me know what you think.

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Moving it back seems like it might be a bit nicer

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Done

CodeCompletionBuilder &Result, const CXXMethodDecl *Function) {
assert(isa<CXXMethodDecl>(Function) &&
Function->hasCXXExplicitFunctionObjectParameter() &&
"Valid only on CXX explicit object methods");

// FIXME: Add ref-qualifier!

// Handle single qualifiers without copying
if (Proto->getMethodQuals().hasOnlyConst()) {
Result.AddInformativeChunk(" const");
const auto Quals = Function->getFunctionObjectParameterType();
if (!Quals.hasQualifiers())
return;
}

if (Proto->getMethodQuals().hasOnlyVolatile()) {
Result.AddInformativeChunk(" volatile");
return;
}
AddFunctionTypeQuals(Result, Quals.getQualifiers());
}

if (Proto->getMethodQuals().hasOnlyRestrict()) {
Result.AddInformativeChunk(" restrict");
return;
}
static void
AddFunctionTypeQualsToCompletionString(CodeCompletionBuilder &Result,
const FunctionDecl *Function) {
if (auto *CxxMethodDecl = llvm::dyn_cast_if_present<CXXMethodDecl>(Function);
CxxMethodDecl && CxxMethodDecl->hasCXXExplicitFunctionObjectParameter()) {
// if explicit object method, infer quals from the object parameter
AddCXXExplicitObjectFunctionTypeQualsToCompletionString(Result,
CxxMethodDecl);
} else {
const auto *Proto = Function->getType()->getAs<FunctionProtoType>();
if (!Proto || !Proto->getMethodQuals())
return;

// Handle multiple qualifiers.
std::string QualsStr;
if (Proto->isConst())
QualsStr += " const";
if (Proto->isVolatile())
QualsStr += " volatile";
if (Proto->isRestrict())
QualsStr += " restrict";
Result.AddInformativeChunk(Result.getAllocator().CopyString(QualsStr));
AddFunctionTypeQuals(Result, Proto->getMethodQuals());
}
}

static void
Expand Down
70 changes: 70 additions & 0 deletions clang/test/CodeCompletion/cpp23-explicit-object.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -81,3 +81,73 @@ struct C {
}
};


struct S {
void foo1(int a);
void foo2(int a) const;
void foo2(this const S& self, float a);
void foo3(this const S& self, int a);
void foo4(this S& self, int a);
};

void S::foo1(int a) {
this->;
// RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:%(line-1):9 -std=c++23 %s | FileCheck -check-prefix=CHECK-CC7 %s
// CHECK-CC7: COMPLETION: foo1 : [#void#]foo1(<#int a#>)
// CHECK-CC7: COMPLETION: foo2 : [#void#]foo2(<#int a#>)[# const#]
// CHECK-CC7: COMPLETION: foo2 : [#void#]foo2(<#float a#>)[# const#]
// CHECK-CC7: COMPLETION: foo3 : [#void#]foo3(<#int a#>)[# const#]
// CHECK-CC7: COMPLETION: foo4 : [#void#]foo4(<#int a#>)
}

void S::foo2(int a) const {
this->;
// RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:%(line-1):9 -std=c++23 %s | FileCheck -check-prefix=CHECK-CC8 %s
// CHECK-CC8: COMPLETION: foo2 : [#void#]foo2(<#int a#>)[# const#]
// CHECK-CC8: COMPLETION: foo2 : [#void#]foo2(<#float a#>)[# const#]
// CHECK-CC8: COMPLETION: foo3 : [#void#]foo3(<#int a#>)[# const#]
}

void S::foo3(this const S& self, int a) {
self.;
// RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:%(line-1):8 -std=c++23 %s | FileCheck -check-prefix=CHECK-CC9 %s
// CHECK-CC9: COMPLETION: foo2 : [#void#]foo2(<#int a#>)[# const#]
// CHECK-CC9: COMPLETION: foo2 : [#void#]foo2(<#float a#>)[# const#]
// CHECK-CC9: COMPLETION: foo3 : [#void#]foo3(<#int a#>)[# const#]
}

void S::foo4(this S& self, int a) {
self.;
// RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:%(line-1):8 -std=c++23 %s | FileCheck -check-prefix=CHECK-CC10 %s
// CHECK-CC10: COMPLETION: foo1 : [#void#]foo1(<#int a#>)
// CHECK-CC10: COMPLETION: foo2 : [#void#]foo2(<#int a#>)[# const#]
// CHECK-CC10: COMPLETION: foo2 : [#void#]foo2(<#float a#>)[# const#]
// CHECK-CC10: COMPLETION: foo3 : [#void#]foo3(<#int a#>)[# const#]
// CHECK-CC10: COMPLETION: foo4 : [#void#]foo4(<#int a#>)
}

void test1(S s) {
s.;
// RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:%(line-1):5 -std=c++23 %s | FileCheck -check-prefix=CHECK-CC11 %s
// CHECK-CC11: COMPLETION: foo1 : [#void#]foo1(<#int a#>)
// CHECK-CC11: COMPLETION: foo2 : [#void#]foo2(<#int a#>)[# const#]
// CHECK-CC11: COMPLETION: foo2 : [#void#]foo2(<#float a#>)[# const#]
// CHECK-CC11: COMPLETION: foo3 : [#void#]foo3(<#int a#>)[# const#]
// CHECK-CC11: COMPLETION: foo4 : [#void#]foo4(<#int a#>)
}

void test2(const S s) {
s.;
// RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:%(line-1):5 -std=c++23 %s | FileCheck -check-prefix=CHECK-CC12 %s
// CHECK-CC12: COMPLETION: foo2 : [#void#]foo2(<#int a#>)[# const#]
// CHECK-CC12: COMPLETION: foo2 : [#void#]foo2(<#float a#>)[# const#]
// CHECK-CC12: COMPLETION: foo3 : [#void#]foo3(<#int a#>)[# const#]
}

void test3(S s) {
s.foo2();
// RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:%(line-1):10 -std=c++23 %s | FileCheck -check-prefix=CHECK-CC13 %s
// CHECK-CC13: OVERLOAD: [#void#]foo2(<#int a#>)
// CHECK-CC13: OVERLOAD: [#void#]foo2(float a)
// TODO: foo2 should be OVERLOAD: [#void#]foo2(<#float a#>)
}
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