Skip to content

[clang-tidy]bugprone-unused-return-value ignore ++ and -- operator overloading #84922

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 4 commits into from
Mar 18, 2024
Merged

[clang-tidy]bugprone-unused-return-value ignore ++ and -- operator overloading #84922

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
d760b28
[clang-tidy]bugprone-unused-return-value ignore `++` and `--` operato…
HerrCai0907 Mar 12, 2024
784df68
better version
HerrCai0907 Mar 13, 2024
e91d1da
fix
HerrCai0907 Mar 14, 2024
623720c
fix
HerrCai0907 Mar 14, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
41 changes: 22 additions & 19 deletions clang-tools-extra/clang-tidy/bugprone/UnusedReturnValueCheck.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -31,9 +31,16 @@ AST_MATCHER_P(FunctionDecl, isInstantiatedFrom, Matcher<FunctionDecl>,
Finder, Builder);
}

AST_MATCHER_P(CXXMethodDecl, isOperatorOverloading,
llvm::SmallVector<OverloadedOperatorKind>, Kinds) {
return llvm::is_contained(Kinds, Node.getOverloadedOperator());
constexpr std::initializer_list<OverloadedOperatorKind>
AssignmentOverloadedOperatorKinds = {
OO_Equal, OO_PlusEqual, OO_MinusEqual, OO_StarEqual,
OO_SlashEqual, OO_PercentEqual, OO_CaretEqual, OO_AmpEqual,
OO_PipeEqual, OO_LessLessEqual, OO_GreaterGreaterEqual, OO_PlusPlus,
OO_MinusMinus};

AST_MATCHER(FunctionDecl, isAssignmentOverloadedOperator) {
return llvm::is_contained(AssignmentOverloadedOperatorKinds,
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

getOverloadedOperator belongs to FunctionDecl, change this from Method to Function, and same in calee, in such case you will also cover calls to free standing operators called directly.

Node.getOverloadedOperator());
}
} // namespace

Expand Down Expand Up @@ -164,22 +171,18 @@ void UnusedReturnValueCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
}

void UnusedReturnValueCheck::registerMatchers(MatchFinder *Finder) {
auto MatchedDirectCallExpr = expr(
callExpr(
callee(functionDecl(
// Don't match void overloads of checked functions.
unless(returns(voidType())),
// Don't match copy or move assignment operator.
unless(cxxMethodDecl(isOperatorOverloading(
{OO_Equal, OO_PlusEqual, OO_MinusEqual, OO_StarEqual,
OO_SlashEqual, OO_PercentEqual, OO_CaretEqual, OO_AmpEqual,
OO_PipeEqual, OO_LessLessEqual, OO_GreaterGreaterEqual}))),
anyOf(
isInstantiatedFrom(
matchers::matchesAnyListedName(CheckedFunctions)),
returns(hasCanonicalType(hasDeclaration(namedDecl(
matchers::matchesAnyListedName(CheckedReturnTypes)))))))))
.bind("match"));
auto MatchedDirectCallExpr =
expr(callExpr(callee(functionDecl(
// Don't match copy or move assignment operator.
unless(isAssignmentOverloadedOperator()),
// Don't match void overloads of checked functions.
unless(returns(voidType())),
anyOf(isInstantiatedFrom(matchers::matchesAnyListedName(
CheckedFunctions)),
returns(hasCanonicalType(hasDeclaration(
namedDecl(matchers::matchesAnyListedName(
CheckedReturnTypes)))))))))
.bind("match"));

auto CheckCastToVoid =
AllowCastToVoid ? castExpr(unless(hasCastKind(CK_ToVoid))) : castExpr();
Expand Down
45 changes: 35 additions & 10 deletions clang-tools-extra/test/clang-tidy/checkers/bugprone/unused-return-value-avoid-assignment.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3,28 +3,53 @@
// RUN: {bugprone-unused-return-value.CheckedFunctions: "::*"}}' \
// RUN: --

struct S {
S(){};
S(S const &);
S(S &&);
S &operator=(S const &);
S &operator=(S &&);
S &operator+=(S);
struct S1 {
S1(){};
S1(S1 const &);
S1(S1 &&);
S1 &operator=(S1 const &);
S1 &operator=(S1 &&);
S1 &operator+=(S1);
S1 &operator++();
S1 &operator++(int);
S1 &operator--();
S1 &operator--(int);
};

S returnValue();
S const &returnRef();
struct S2 {
S2(){};
S2(S2 const &);
S2(S2 &&);
};

S2 &operator-=(S2&, int);
S2 &operator++(S2 &);
S2 &operator++(S2 &, int);

S1 returnValue();
S1 const &returnRef();

void bar() {
returnValue();
// CHECK-MESSAGES: [[@LINE-1]]:3: warning: the value returned by this function should not be disregarded; neglecting it may lead to errors

S a{};
S1 a{};
a = returnValue();
a.operator=(returnValue());

a = returnRef();
a.operator=(returnRef());

a += returnRef();

a++;
++a;
a--;
--a;

S2 b{};

b -= 1;
b++;
++b;
}