clang/test/SemaCXX/warn-redundant-move.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -Wredundant-move -std=c++11 -verify %s
   2 // RUN: %clang_cc1 -fsyntax-only -Wredundant-move -std=c++11 -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
   3 // RUN: %clang_cc1 -fsyntax-only -std=c++11 %s -ast-dump | FileCheck %s --check-prefix=CHECK-AST
   4
   5 // definitions for std::move
   6 namespace std {
   7 inline namespace foo {
   8 template <class T> struct remove_reference { typedef T type; };
   9 template <class T> struct remove_reference<T&> { typedef T type; };
  10 template <class T> struct remove_reference<T&&> { typedef T type; };
  11
  12 template <class T> typename remove_reference<T>::type &&move(T &&t);
  13 }
  14 }
  15
  16 // test1 and test2 should not warn until after implementation of DR1579.
  17 struct A {};
  18 struct B : public A {};
  19
  20 A test1(B b1) {
  21   B b2;
  22   return b1;
  23   return b2;
  24   return std::move(b1);
  25   return std::move(b2);
  26 }
  27
  28 struct C {
  29   C() {}
  30   C(A) {}
  31 };
  32
  33 C test2(A a1, B b1) {
  34   A a2;
  35   B b2;
  36
  37   return a1;
  38   return a2;
  39   return b1;
  40   return b2;
  41
  42   return std::move(a1);
  43   return std::move(a2);
  44   return std::move(b1);
  45   return std::move(b2);
  46 }
  47
  48 // Copy of tests above with types changed to reference types.
  49 A test3(B& b1) {
  50   B& b2 = b1;
  51   return b1;
  52   return b2;
  53   return std::move(b1);
  54   return std::move(b2);
  55 }
  56
  57 C test4(A& a1, B& b1) {
  58   A& a2 = a1;
  59   B& b2 = b1;
  60
  61   return a1;
  62   return a2;
  63   return b1;
  64   return b2;
  65
  66   return std::move(a1);
  67   return std::move(a2);
  68   return std::move(b1);
  69   return std::move(b2);
  70 }
  71
  72 // PR23819, case 2
  73 struct D {};
  74 D test5(D d) {
  75   return d;
  76   // Verify the implicit move from the AST dump
  77   // CHECK-AST: ReturnStmt{{.*}}line:[[@LINE-2]]
  78   // CHECK-AST-NEXT: CXXConstructExpr{{.*}}D{{.*}}void (D &&)
  79   // CHECK-AST-NEXT: ImplicitCastExpr
  80   // CHECK-AST-NEXT: DeclRefExpr{{.*}}ParmVar{{.*}}'d'
  81
  82   return std::move(d);
  83   // expected-warning@-1{{redundant move in return statement}}
  84   // expected-note@-2{{remove std::move call here}}
  85   // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:10-[[@LINE-3]]:20}:""
  86   // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:21-[[@LINE-4]]:22}:""
  87 }
  88
  89 namespace templates {
  90   struct A {};
  91   struct B { B(A); };
  92
  93   // Warn once here since the type is not dependent.
  94   template <typename T>
  95   A test1(A a) {
  96     return std::move(a);
  97     // expected-warning@-1{{redundant move in return statement}}
  98     // expected-note@-2{{remove std::move call here}}
  99     // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:12-[[@LINE-3]]:22}:""
 100     // CHECK: fix-it:"{{.*}}":{[[@LINE-4]]:23-[[@LINE-4]]:24}:""
 101   }
 102   void run_test1() {
 103     test1<A>(A());
 104     test1<B>(A());
 105   }
 106
 107   // T1 and T2 may not be the same, the warning may not always apply.
 108   template <typename T1, typename T2>
 109   T1 test2(T2 t) {
 110     return std::move(t);
 111   }
 112   void run_test2() {
 113     test2<A, A>(A());
 114     test2<B, A>(A());
 115   }
 116 }