void MoveConstArgCheck::check(const MatchFinder::MatchResult &Result) {
const auto *CallMove = Result.Nodes.getNodeAs<CallExpr>("call-move");
const auto *ReceivingExpr = Result.Nodes.getNodeAs<Expr>("receiving-expr");
const Expr *Arg = CallMove->getArg(0);
SourceManager &SM = Result.Context->getSourceManager();
CharSourceRange MoveRange =
CharSourceRange::getCharRange(CallMove->getSourceRange());
CharSourceRange FileMoveRange =
Lexer::makeFileCharRange(MoveRange, SM, getLangOpts());
if (!FileMoveRange.isValid())
return;
bool IsConstArg = Arg->getType().isConstQualified();
bool IsTriviallyCopyable =
Arg->getType().isTriviallyCopyableType(*Result.Context);
if (IsConstArg || IsTriviallyCopyable) {
if (const CXXRecordDecl *R = Arg->getType()->getAsCXXRecordDecl()) {
// According to [expr.prim.lambda]p3, "whether the closure type is
// trivially copyable" property can be changed by the implementation of
// the language, so we shouldn't rely on it when issuing diagnostics.
if (R->isLambda())
return;
// Don't warn when the type is not copyable.
for (const auto *Ctor : R->ctors()) {
if (Ctor->isCopyConstructor() && Ctor->isDeleted())
return;
}
}
if (!IsConstArg && IsTriviallyCopyable && !CheckTriviallyCopyableMove)
return;
bool IsVariable = isa<DeclRefExpr>(Arg);
const auto *Var =
IsVariable ? dyn_cast<DeclRefExpr>(Arg)->getDecl() : nullptr;
auto Diag = diag(FileMoveRange.getBegin(),
"std::move of the %select{|const }0"
"%select{expression|variable %4}1 "
"%select{|of the trivially-copyable type %5 }2"
"has no effect; remove std::move()"
"%select{| or make the variable non-const}3")
<< IsConstArg << IsVariable << IsTriviallyCopyable
<< (IsConstArg && IsVariable && !IsTriviallyCopyable) << Var
<< Arg->getType();
ReplaceCallWithArg(CallMove, Diag, SM, getLangOpts());
} else if (ReceivingExpr) {
auto Diag = diag(FileMoveRange.getBegin(),
"passing result of std::move() as a const reference "
"argument; no move will actually happen");
ReplaceCallWithArg(CallMove, Diag, SM, getLangOpts());
}
}
void MoveConstantArgumentCheck::check(const MatchFinder::MatchResult &Result) {
const auto *CallMove = Result.Nodes.getNodeAs<CallExpr>("call-move");
const auto *ReceivingExpr = Result.Nodes.getNodeAs<Expr>("receiving-expr");
const Expr *Arg = CallMove->getArg(0);
SourceManager &SM = Result.Context->getSourceManager();
CharSourceRange MoveRange =
CharSourceRange::getCharRange(CallMove->getSourceRange());
CharSourceRange FileMoveRange =
Lexer::makeFileCharRange(MoveRange, SM, getLangOpts());
if (!FileMoveRange.isValid())
return;
bool IsConstArg = Arg->getType().isConstQualified();
bool IsTriviallyCopyable =
Arg->getType().isTriviallyCopyableType(*Result.Context);
if (IsConstArg || IsTriviallyCopyable) {
bool IsVariable = isa<DeclRefExpr>(Arg);
const auto *Var =
IsVariable ? dyn_cast<DeclRefExpr>(Arg)->getDecl() : nullptr;
auto Diag = diag(FileMoveRange.getBegin(),
"std::move of the %select{|const }0"
"%select{expression|variable %4}1 "
"%select{|of the trivially-copyable type %5 }2"
"has no effect; remove std::move()"
"%select{| or make the variable non-const}3")
<< IsConstArg << IsVariable << IsTriviallyCopyable
<< (IsConstArg && IsVariable && !IsTriviallyCopyable) << Var
<< Arg->getType();
ReplaceCallWithArg(CallMove, Diag, SM, getLangOpts());
} else if (ReceivingExpr) {
auto Diag = diag(FileMoveRange.getBegin(),
"passing result of std::move() as a const reference "
"argument; no move will actually happen");
ReplaceCallWithArg(CallMove, Diag, SM, getLangOpts());
}
}
