More helpful diagnostic on casts between unrelated class hierarchies.

llvm-svn: 227371
This commit is contained in:
Nathan Sidwell 2015-01-28 21:31:26 +00:00
parent 949389c395
commit ffa7dc379f
4 changed files with 48 additions and 4 deletions

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@ -5267,6 +5267,11 @@ def err_bad_cstyle_cast_overload : Error<
def err_bad_cxx_cast_generic : Error< def err_bad_cxx_cast_generic : Error<
"%select{const_cast|static_cast|reinterpret_cast|dynamic_cast|C-style cast|" "%select{const_cast|static_cast|reinterpret_cast|dynamic_cast|C-style cast|"
"functional-style cast}0 from %1 to %2 is not allowed">; "functional-style cast}0 from %1 to %2 is not allowed">;
def err_bad_cxx_cast_unrelated_class : Error<
"%select{const_cast|static_cast|reinterpret_cast|dynamic_cast|C-style cast|"
"functional-style cast}0 from %1 to %2, which are not related by "
"inheritance, is not allowed">;
def note_type_incomplete : Note<"%0 is incomplete">;
def err_bad_cxx_cast_rvalue : Error< def err_bad_cxx_cast_rvalue : Error<
"%select{const_cast|static_cast|reinterpret_cast|dynamic_cast|C-style cast|" "%select{const_cast|static_cast|reinterpret_cast|dynamic_cast|C-style cast|"
"functional-style cast}0 from rvalue to reference type %2">; "functional-style cast}0 from rvalue to reference type %2">;

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@ -389,6 +389,33 @@ static void diagnoseBadCast(Sema &S, unsigned msg, CastType castType,
S.Diag(opRange.getBegin(), msg) << castType S.Diag(opRange.getBegin(), msg) << castType
<< src->getType() << destType << opRange << src->getSourceRange(); << src->getType() << destType << opRange << src->getSourceRange();
// Detect if both types are (ptr to) class, and note any incompleteness.
int DifferentPtrness = 0;
QualType From = destType;
if (auto Ptr = From->getAs<PointerType>()) {
From = Ptr->getPointeeType();
DifferentPtrness++;
}
QualType To = src->getType();
if (auto Ptr = To->getAs<PointerType>()) {
To = Ptr->getPointeeType();
DifferentPtrness--;
}
if (!DifferentPtrness) {
auto RecFrom = From->getAs<RecordType>();
auto RecTo = To->getAs<RecordType>();
if (RecFrom && RecTo) {
auto DeclFrom = RecFrom->getAsCXXRecordDecl();
if (!DeclFrom->isCompleteDefinition())
S.Diag(DeclFrom->getLocation(), diag::note_type_incomplete)
<< DeclFrom->getDeclName();
auto DeclTo = RecTo->getAsCXXRecordDecl();
if (!DeclTo->isCompleteDefinition())
S.Diag(DeclTo->getLocation(), diag::note_type_incomplete)
<< DeclTo->getDeclName();
}
}
} }
/// UnwrapDissimilarPointerTypes - Like Sema::UnwrapSimilarPointerTypes, /// UnwrapDissimilarPointerTypes - Like Sema::UnwrapSimilarPointerTypes,
@ -1079,6 +1106,14 @@ static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr,
if (!CStyle && if (!CStyle &&
Self.CheckTollFreeBridgeStaticCast(DestType, SrcExpr.get(), Kind)) Self.CheckTollFreeBridgeStaticCast(DestType, SrcExpr.get(), Kind))
return TC_Success; return TC_Success;
// See if it looks like the user is trying to convert between
// related record types, and select a better diagnostic if so.
if (auto SrcPointer = SrcType->getAs<PointerType>())
if (auto DestPointer = DestType->getAs<PointerType>())
if (SrcPointer->getPointeeType()->getAs<RecordType>() &&
DestPointer->getPointeeType()->getAs<RecordType>())
msg = diag::err_bad_cxx_cast_unrelated_class;
// We tried everything. Everything! Nothing works! :-( // We tried everything. Everything! Nothing works! :-(
return TC_NotApplicable; return TC_NotApplicable;

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@ -1,5 +1,5 @@
// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify %s // RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify %s
template<typename T> struct X; template<typename T> struct X; // expected-note {{'X' is incomplete}}
template<int I> struct Y; template<int I> struct Y;
X<X<int>> *x1; X<X<int>> *x1;

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@ -9,8 +9,8 @@ struct F : public C1 {}; // Single path to B with virtual.
struct G1 : public B {}; struct G1 : public B {};
struct G2 : public B {}; struct G2 : public B {};
struct H : public G1, public G2 {}; // Ambiguous path to B. struct H : public G1, public G2 {}; // Ambiguous path to B.
struct I; // Incomplete. struct I; // Incomplete. expected-note {{'I' is incomplete}}
struct J; // Incomplete. struct J; // Incomplete. expected-note {{'J' is incomplete}}
enum Enum { En1, En2 }; enum Enum { En1, En2 };
enum Onom { On1, On2 }; enum Onom { On1, On2 };
@ -92,9 +92,13 @@ void t_529_5_8()
(void)static_cast<E&>(*((A*)0)); // expected-error {{cannot cast private base class 'A' to 'E'}} (void)static_cast<E&>(*((A*)0)); // expected-error {{cannot cast private base class 'A' to 'E'}}
(void)static_cast<H*>((A*)0); // expected-error {{ambiguous cast from base 'A' to derived 'H':\n struct A -> struct B -> struct G1 -> struct H\n struct A -> struct B -> struct G2 -> struct H}} (void)static_cast<H*>((A*)0); // expected-error {{ambiguous cast from base 'A' to derived 'H':\n struct A -> struct B -> struct G1 -> struct H\n struct A -> struct B -> struct G2 -> struct H}}
(void)static_cast<H&>(*((A*)0)); // expected-error {{ambiguous cast from base 'A' to derived 'H':\n struct A -> struct B -> struct G1 -> struct H\n struct A -> struct B -> struct G2 -> struct H}} (void)static_cast<H&>(*((A*)0)); // expected-error {{ambiguous cast from base 'A' to derived 'H':\n struct A -> struct B -> struct G1 -> struct H\n struct A -> struct B -> struct G2 -> struct H}}
(void)static_cast<E*>((B*)0); // expected-error {{static_cast from 'B *' to 'E *' is not allowed}} (void)static_cast<E*>((B*)0); // expected-error {{static_cast from 'B *' to 'E *', which are not related by inheritance, is not allowed}}
(void)static_cast<E&>(*((B*)0)); // expected-error {{non-const lvalue reference to type 'E' cannot bind to a value of unrelated type 'B'}} (void)static_cast<E&>(*((B*)0)); // expected-error {{non-const lvalue reference to type 'E' cannot bind to a value of unrelated type 'B'}}
(void)static_cast<E*>((J*)0); // expected-error {{static_cast from 'J *' to 'E *', which are not related by inheritance, is not allowed}}
(void)static_cast<I*>((B*)0); // expected-error {{static_cast from 'B *' to 'I *', which are not related by inheritance, is not allowed}}
// TODO: Test inaccessible base in context where it's accessible, i.e. // TODO: Test inaccessible base in context where it's accessible, i.e.
// member function and friend. // member function and friend.