r236075 - Add -Wpessimizing-move and -Wredundant-move warnings.
Richard Trieu
rtrieu at google.com
Tue Apr 28 20:59:19 PDT 2015
Since this warning did not exist when std::move was first introduced, and
many people are not familiar with copy elision rules, there have been a lot
of uses of the pessimizing move pattern. In relative numbers, the
pessimizing move warning is over 5x more common than either the range loop
warning (-Wrange-loop-analysis) or the proposed comma warning (-Wcomma).
With such a high occurrence, it seemed better not to have it on by default.
On Tue, Apr 28, 2015 at 7:17 PM, Nico Weber <thakis at chromium.org> wrote:
> Why are these DefaultIgnore?
>
> On Tue, Apr 28, 2015 at 6:52 PM, Richard Trieu <rtrieu at google.com> wrote:
>
>> Author: rtrieu
>> Date: Tue Apr 28 20:52:17 2015
>> New Revision: 236075
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=236075&view=rev
>> Log:
>> Add -Wpessimizing-move and -Wredundant-move warnings.
>>
>> -Wpessimizing-move warns when a call to std::move would prevent copy
>> elision
>> if the argument was not wrapped in a call. This happens when moving a
>> local
>> variable in a return statement when the variable is the same type as the
>> return type or using a move to create a new object from a temporary
>> object.
>>
>> -Wredundant-move warns when an implicit move would already be made, so the
>> std::move call is not needed, such as when moving a local variable in a
>> return
>> that is different from the return type.
>>
>> Differential Revision: http://reviews.llvm.org/D7633
>>
>> Added:
>> cfe/trunk/test/SemaCXX/warn-pessmizing-move.cpp
>> cfe/trunk/test/SemaCXX/warn-redundant-move.cpp
>> Modified:
>> cfe/trunk/include/clang/Basic/DiagnosticGroups.td
>> cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>> cfe/trunk/lib/Sema/SemaInit.cpp
>>
>> Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticGroups.td?rev=236075&r1=236074&r2=236075&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/include/clang/Basic/DiagnosticGroups.td (original)
>> +++ cfe/trunk/include/clang/Basic/DiagnosticGroups.td Tue Apr 28 20:52:17
>> 2015
>> @@ -286,6 +286,7 @@ def DeprecatedObjCIsaUsage : DiagGroup<"
>> def ExplicitInitializeCall : DiagGroup<"explicit-initialize-call">;
>> def Packed : DiagGroup<"packed">;
>> def Padded : DiagGroup<"padded">;
>> +def PessimizingMove : DiagGroup<"pessimizing-move">;
>> def PointerArith : DiagGroup<"pointer-arith">;
>> def PoundWarning : DiagGroup<"#warnings">;
>> def PoundPragmaMessage : DiagGroup<"#pragma-messages">,
>> @@ -294,6 +295,7 @@ def : DiagGroup<"pointer-to-int-cast">;
>> def : DiagGroup<"redundant-decls">;
>> def RedeclaredClassMember : DiagGroup<"redeclared-class-member">;
>> def GNURedeclaredEnum : DiagGroup<"gnu-redeclared-enum">;
>> +def RedundantMove : DiagGroup<"redundant-move">;
>> def ReturnStackAddress : DiagGroup<"return-stack-address">;
>> def ReturnTypeCLinkage : DiagGroup<"return-type-c-linkage">;
>> def ReturnType : DiagGroup<"return-type", [ReturnTypeCLinkage]>;
>>
>> Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=236075&r1=236074&r2=236075&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
>> +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Tue Apr 28
>> 20:52:17 2015
>> @@ -4777,6 +4777,17 @@ def warn_self_move : Warning<
>> "explicitly moving variable of type %0 to itself">,
>> InGroup<SelfMove>, DefaultIgnore;
>>
>> +def warn_redundant_move_on_return : Warning<
>> + "redundant move in return statement">,
>> + InGroup<RedundantMove>, DefaultIgnore;
>> +def warn_pessimizing_move_on_return : Warning<
>> + "moving a local object in a return statement prevents copy elision">,
>> + InGroup<PessimizingMove>, DefaultIgnore;
>> +def warn_pessimizing_move_on_initialization : Warning<
>> + "moving a temporary object prevents copy elision">,
>> + InGroup<PessimizingMove>, DefaultIgnore;
>> +def note_remove_move : Note<"remove std::move call here">;
>> +
>> def warn_string_plus_int : Warning<
>> "adding %0 to a string does not append to the string">,
>> InGroup<StringPlusInt>;
>>
>> Modified: cfe/trunk/lib/Sema/SemaInit.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaInit.cpp?rev=236075&r1=236074&r2=236075&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/Sema/SemaInit.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaInit.cpp Tue Apr 28 20:52:17 2015
>> @@ -5768,6 +5768,112 @@ static void DiagnoseNarrowingInInitList(
>> QualType EntityType,
>> const Expr *PostInit);
>>
>> +/// Provide warnings when std::move is used on construction.
>> +static void CheckMoveOnConstruction(Sema &S, const Expr *InitExpr,
>> + bool IsReturnStmt) {
>> + if (!InitExpr)
>> + return;
>> +
>> + QualType DestType = InitExpr->getType();
>> + if (!DestType->isRecordType())
>> + return;
>> +
>> + unsigned DiagID = 0;
>> + if (IsReturnStmt) {
>> + const CXXConstructExpr *CCE =
>> + dyn_cast<CXXConstructExpr>(InitExpr->IgnoreParens());
>> + if (!CCE || CCE->getNumArgs() != 1)
>> + return;
>> +
>> + if (!CCE->getConstructor()->isCopyOrMoveConstructor())
>> + return;
>> +
>> + InitExpr = CCE->getArg(0)->IgnoreImpCasts();
>> +
>> + // Remove implicit temporary and constructor nodes.
>> + if (const MaterializeTemporaryExpr *MTE =
>> + dyn_cast<MaterializeTemporaryExpr>(InitExpr)) {
>> + InitExpr = MTE->GetTemporaryExpr()->IgnoreImpCasts();
>> + while (const CXXConstructExpr *CCE =
>> + dyn_cast<CXXConstructExpr>(InitExpr)) {
>> + if (isa<CXXTemporaryObjectExpr>(CCE))
>> + return;
>> + if (CCE->getNumArgs() == 0)
>> + return;
>> + if (CCE->getNumArgs() > 1 &&
>> !isa<CXXDefaultArgExpr>(CCE->getArg(1)))
>> + return;
>> + InitExpr = CCE->getArg(0);
>> + }
>> + InitExpr = InitExpr->IgnoreImpCasts();
>> + DiagID = diag::warn_redundant_move_on_return;
>> + }
>> + }
>> +
>> + // Find the std::move call and get the argument.
>> + const CallExpr *CE = dyn_cast<CallExpr>(InitExpr->IgnoreParens());
>> + if (!CE || CE->getNumArgs() != 1)
>> + return;
>> +
>> + const FunctionDecl *MoveFunction = CE->getDirectCallee();
>> + if (!MoveFunction || !MoveFunction->isInStdNamespace() ||
>> + !MoveFunction->getIdentifier() ||
>> + !MoveFunction->getIdentifier()->isStr("move"))
>> + return;
>> +
>> + const Expr *Arg = CE->getArg(0)->IgnoreImplicit();
>> +
>> + if (IsReturnStmt) {
>> + const DeclRefExpr *DRE =
>> dyn_cast<DeclRefExpr>(Arg->IgnoreParenImpCasts());
>> + if (!DRE || DRE->refersToEnclosingVariableOrCapture())
>> + return;
>> +
>> + const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl());
>> + if (!VD || !VD->hasLocalStorage())
>> + return;
>> +
>> + if (DiagID == 0) {
>> + DiagID = S.Context.hasSameUnqualifiedType(DestType, VD->getType())
>> + ? diag::warn_pessimizing_move_on_return
>> + : diag::warn_redundant_move_on_return;
>> + }
>> + } else {
>> + DiagID = diag::warn_pessimizing_move_on_initialization;
>> + const Expr *ArgStripped = Arg->IgnoreImplicit()->IgnoreParens();
>> + if (!ArgStripped->isRValue() ||
>> !ArgStripped->getType()->isRecordType())
>> + return;
>> + }
>> +
>> + S.Diag(CE->getLocStart(), DiagID);
>> +
>> + // Get all the locations for a fix-it. Don't emit the fix-it if any
>> location
>> + // is within a macro.
>> + SourceLocation CallBegin = CE->getCallee()->getLocStart();
>> + if (CallBegin.isMacroID())
>> + return;
>> + SourceLocation RParen = CE->getRParenLoc();
>> + if (RParen.isMacroID())
>> + return;
>> + SourceLocation LParen;
>> + SourceLocation ArgLoc = Arg->getLocStart();
>> +
>> + // Special testing for the argument location. Since the fix-it needs
>> the
>> + // location right before the argument, the argument location can be in
>> a
>> + // macro only if it is at the beginning of the macro.
>> + while (ArgLoc.isMacroID() &&
>> +
>> S.getSourceManager().isAtStartOfImmediateMacroExpansion(ArgLoc)) {
>> + ArgLoc =
>> S.getSourceManager().getImmediateExpansionRange(ArgLoc).first;
>> + }
>> +
>> + if (LParen.isMacroID())
>> + return;
>> +
>> + LParen = ArgLoc.getLocWithOffset(-1);
>> +
>> + S.Diag(CE->getLocStart(), diag::note_remove_move)
>> + << FixItHint::CreateRemoval(SourceRange(CallBegin, LParen))
>> + << FixItHint::CreateRemoval(SourceRange(RParen, RParen));
>> +}
>> +
>> ExprResult
>> InitializationSequence::Perform(Sema &S,
>> const InitializedEntity &Entity,
>> @@ -6497,6 +6603,12 @@ InitializationSequence::Perform(Sema &S,
>> cast<FieldDecl>(Entity.getDecl()),
>> CurInit.get());
>>
>> + // Check for std::move on construction.
>> + if (const Expr *E = CurInit.get()) {
>> + CheckMoveOnConstruction(S, E,
>> + Entity.getKind() ==
>> InitializedEntity::EK_Result);
>> + }
>> +
>> return CurInit;
>> }
>>
>>
>> Added: cfe/trunk/test/SemaCXX/warn-pessmizing-move.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-pessmizing-move.cpp?rev=236075&view=auto
>>
>> ==============================================================================
>> --- cfe/trunk/test/SemaCXX/warn-pessmizing-move.cpp (added)
>> +++ cfe/trunk/test/SemaCXX/warn-pessmizing-move.cpp Tue Apr 28 20:52:17
>> 2015
>> @@ -0,0 +1,203 @@
>> +// RUN: %clang_cc1 -fsyntax-only -Wpessimizing-move -std=c++11 -verify %s
>> +// RUN: %clang_cc1 -fsyntax-only -Wpessimizing-move -std=c++11
>> -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
>> +
>> +// definitions for std::move
>> +namespace std {
>> +inline namespace foo {
>> +template <class T> struct remove_reference { typedef T type; };
>> +template <class T> struct remove_reference<T&> { typedef T type; };
>> +template <class T> struct remove_reference<T&&> { typedef T type; };
>> +
>> +template <class T> typename remove_reference<T>::type &&move(T &&t);
>> +}
>> +}
>> +
>> +struct A {};
>> +struct B {
>> + B() {}
>> + B(A) {}
>> +};
>> +
>> +A test1(A a1) {
>> + A a2;
>> + return a1;
>> + return a2;
>> + return std::move(a1);
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:22-[[@LINE-4]]:23}:""
>> + return std::move(a2);
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:22-[[@LINE-4]]:23}:""
>> +}
>> +
>> +B test2(A a1, B b1) {
>> + // Object is different than return type so don't warn.
>> + A a2;
>> + return a1;
>> + return a2;
>> + return std::move(a1);
>> + return std::move(a2);
>> +
>> + B b2;
>> + return b1;
>> + return b2;
>> + return std::move(b1);
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:22-[[@LINE-4]]:23}:""
>> + return std::move(b2);
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:22-[[@LINE-4]]:23}:""
>> +}
>> +
>> +A global_a;
>> +A test3() {
>> + // Don't warn when object is not local.
>> + return global_a;
>> + return std::move(global_a);
>> + static A static_a;
>> + return static_a;
>> + return std::move(static_a);
>> +
>> +}
>> +
>> +A test4() {
>> + return A();
>> + return test3();
>> +
>> + return std::move(A());
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:23-[[@LINE-4]]:24}:""
>> + return std::move(test3());
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:27-[[@LINE-4]]:28}:""
>> +}
>> +
>> +void test5(A) {
>> + test5(A());
>> + test5(test4());
>> +
>> + test5(std::move(A()));
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:9-[[@LINE-3]]:19}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:22-[[@LINE-4]]:23}:""
>> + test5(std::move(test4()));
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:9-[[@LINE-3]]:19}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:26-[[@LINE-4]]:27}:""
>> +}
>> +
>> +void test6() {
>> + A a1 = A();
>> + A a2 = test3();
>> +
>> + A a3 = std::move(A());
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:23-[[@LINE-4]]:24}:""
>> + A a4 = std::move(test3());
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:27-[[@LINE-4]]:28}:""
>> +}
>> +
>> +A test7() {
>> + A a1 = std::move(A());
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:23-[[@LINE-4]]:24}:""
>> + A a2 = std::move((A()));
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:25-[[@LINE-4]]:26}:""
>> + A a3 = (std::move(A()));
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:11-[[@LINE-3]]:21}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:24-[[@LINE-4]]:25}:""
>> + A a4 = (std::move((A())));
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:11-[[@LINE-3]]:21}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:26-[[@LINE-4]]:27}:""
>> +
>> + return std::move(a1);
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:22-[[@LINE-4]]:23}:""
>> + return std::move((a1));
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:24-[[@LINE-4]]:25}:""
>> + return (std::move(a1));
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:11-[[@LINE-3]]:21}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:23-[[@LINE-4]]:24}:""
>> + return (std::move((a1)));
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:11-[[@LINE-3]]:21}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:25-[[@LINE-4]]:26}:""
>> +}
>> +
>> +#define wrap1(x) x
>> +#define wrap2(x) x
>> +
>> +// Macro test. Since the std::move call is outside the macro, it is
>> +// safe to suggest a fix-it.
>> +A test8(A a) {
>> + return std::move(a);
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:21-[[@LINE-4]]:22}:""
>> + return std::move(wrap1(a));
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:28-[[@LINE-4]]:29}:""
>> + return std::move(wrap1(wrap2(a)));
>> + // expected-warning at -1{{prevents copy elision}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:35-[[@LINE-4]]:36}:""
>> +}
>> +
>> +#define test9 \
>> + A test9(A a) { \
>> + return std::move(a); \
>> + }
>> +
>> +// Macro test. The std::call is inside the macro, so no fix-it is
>> suggested.
>> +test9
>> +// expected-warning at -1{{prevents copy elision}}
>> +// CHECK-NOT: fix-it
>> +
>> +#define return_a return std::move(a)
>> +
>> +// Macro test. The std::call is inside the macro, so no fix-it is
>> suggested.
>> +A test10(A a) {
>> + return_a;
>> + // expected-warning at -1{{prevents copy elision}}
>> + // CHECK-NOT: fix-it
>> +}
>>
>> Added: cfe/trunk/test/SemaCXX/warn-redundant-move.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-redundant-move.cpp?rev=236075&view=auto
>>
>> ==============================================================================
>> --- cfe/trunk/test/SemaCXX/warn-redundant-move.cpp (added)
>> +++ cfe/trunk/test/SemaCXX/warn-redundant-move.cpp Tue Apr 28 20:52:17
>> 2015
>> @@ -0,0 +1,68 @@
>> +// RUN: %clang_cc1 -fsyntax-only -Wredundant-move -std=c++11 -verify %s
>> +// RUN: %clang_cc1 -fsyntax-only -Wredundant-move -std=c++11
>> -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
>> +
>> +// definitions for std::move
>> +namespace std {
>> +inline namespace foo {
>> +template <class T> struct remove_reference { typedef T type; };
>> +template <class T> struct remove_reference<T&> { typedef T type; };
>> +template <class T> struct remove_reference<T&&> { typedef T type; };
>> +
>> +template <class T> typename remove_reference<T>::type &&move(T &&t);
>> +}
>> +}
>> +
>> +struct A {};
>> +struct B : public A {};
>> +
>> +A test1(B b1) {
>> + B b2;
>> + //return b1;
>> + //return b2;
>> + return std::move(b1);
>> + // expected-warning at -1{{redundant move}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:22-[[@LINE-4]]:23}:""
>> + return std::move(b2);
>> + // expected-warning at -1{{redundant move}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:22-[[@LINE-4]]:23}:""
>> +}
>> +
>> +struct C {
>> + C() {}
>> + C(A) {}
>> +};
>> +
>> +C test2(A a1, B b1) {
>> + A a2;
>> + B b2;
>> +
>> + return a1;
>> + return a2;
>> + return b1;
>> + return b2;
>> +
>> + return std::move(a1);
>> + // expected-warning at -1{{redundant move}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:22-[[@LINE-4]]:23}:""
>> + return std::move(a2);
>> + // expected-warning at -1{{redundant move}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:22-[[@LINE-4]]:23}:""
>> + return std::move(b1);
>> + // expected-warning at -1{{redundant move}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:22-[[@LINE-4]]:23}:""
>> + return std::move(b2);
>> + // expected-warning at -1{{redundant move}}
>> + // expected-note at -2{{remove std::move call}}
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
>> + // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:22-[[@LINE-4]]:23}:""
>> +}
>>
>>
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