Commit 41fcd172 authored by Mark de Wever's avatar Mark de Wever
Browse files

[Sema] Avoid Wrange-loop-analysis false positives 

When Wrange-loop-analysis issues a diagnostic on a dependent type in a
template the diagnostic may not be valid for all instantiations. Therefore
the diagnostic is suppressed during the instantiation. Non dependent types
still issue a diagnostic.

The same can happen when using macros. Therefore the diagnostic is
disabled for macros.

Fixes https://bugs.llvm.org/show_bug.cgi?id=44556

Differential Revision: https://reviews.llvm.org/D73007
parent 6b9a5e6f

clang/lib/Sema/SemaStmt.cpp

+6 −0
Original line number Diff line number Diff line
@@ -2838,6 +2838,9 @@ static void DiagnoseForRangeConstVariableCopies(Sema &SemaRef, 
///    Suggest "const foo &x" to prevent the copy.

static void DiagnoseForRangeVariableCopies(Sema &SemaRef,

                                           const CXXForRangeStmt *ForStmt) {

  if (SemaRef.inTemplateInstantiation())

    return;



  if (SemaRef.Diags.isIgnored(diag::warn_for_range_const_reference_copy,

                              ForStmt->getBeginLoc()) &&

      SemaRef.Diags.isIgnored(diag::warn_for_range_variable_always_copy,
@@ -2860,6 +2863,9 @@ static void DiagnoseForRangeVariableCopies(Sema &SemaRef, 
  if (!InitExpr)

    return;



  if (InitExpr->getExprLoc().isMacroID())

    return;



  if (VariableType->isReferenceType()) {

    DiagnoseForRangeReferenceVariableCopies(SemaRef, VD,

                                            ForStmt->getRangeInit()->getType());

clang/test/SemaCXX/warn-range-loop-analysis.cpp

+72 −0
Original line number Diff line number Diff line
@@ -454,3 +454,75 @@ void test10() { 
  // expected-note@-2 {{'Bar'}}

  // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:17-[[@LINE-3]]:18}:" "

}



template <class T>

void test_template_function() {

  // In a template instantiation the diagnostics should not be emitted for

  // loops with dependent types.

  Container<Bar> C;

  for (const Bar &x : C) {}

  // expected-warning@-1 {{always a copy}}

  // expected-note@-2 {{'Bar'}}

  // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:18-[[@LINE-3]]:19}:""



  Container<T> Dependent;

  for (const T &x : Dependent) {}

}

template void test_template_function<Bar>();



template <class T>

struct test_template_struct {

  static void static_member() {

    Container<Bar> C;

    for (const Bar &x : C) {}

    // expected-warning@-1 {{always a copy}}

    // expected-note@-2 {{'Bar'}}

    // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:20-[[@LINE-3]]:21}:""



    Container<T> Dependent;

    for (const T &x : Dependent) {}

  }



  void member() {

    Container<Bar> C;

    for (const Bar &x : C) {}

    // expected-warning@-1 {{always a copy}}

    // expected-note@-2 {{'Bar'}}

    // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:20-[[@LINE-3]]:21}:""



    Container<T> Dependent;

    for (const T &x : Dependent) {}

  }

};

template struct test_template_struct<Bar>;



struct test_struct_with_templated_member {

  void member() {

    Container<Bar> C;

    for (const Bar &x : C) {}

    // expected-warning@-1 {{always a copy}}

    // expected-note@-2 {{'Bar'}}

    // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:20-[[@LINE-3]]:21}:""

  }



  template <class T>

  void template_member() {

    Container<Bar> C;

    for (const Bar &x : C) {}

    // expected-warning@-1 {{always a copy}}

    // expected-note@-2 {{'Bar'}}

    // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:20-[[@LINE-3]]:21}:""



    Container<T> Dependent;

    for (const T &x : Dependent) {}

  }

};

template void test_struct_with_templated_member::template_member<Bar>();



#define TEST_MACRO            \

  void test_macro() {         \

    Container<Bar> C;         \

    for (const Bar &x : C) {} \

  }



TEST_MACRO