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Instantiate exception specifications when instantiating function types (other

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than the type of a function declaration). We previously didn't instantiate
these at all! This also covers the pathological case where the only mention of
a parameter pack is within the exception specification; this gives us a second
way (other than alias templates) to reach the horrible state where a type
contains an unexpanded pack, but its canonical type does not.


This is a re-commit of r219977:

r219977 was reverted in r220038 because it hit a wrong-code bug in GCC 4.7.2.
(That's gcc.gnu.org/PR56135, and affects any implicit lambda-capture of
'this' within a template.)


r219977 was a re-commit of r217995, r218011, and r218053:

r217995 was reverted in r218058 because it hit a rejects-valid bug in MSVC.
(Incorrect overload resolution in the presence of using-declarations.)
It was re-committed in r219977 with a workaround for the MSVC rejects-valid.

r218011 was a workaround for an MSVC parser bug. (Incorrect desugaring of
unbraced range-based for loop).

llvm-svn: 221750
This commit is contained in:
Richard Smith
2014-11-12 02:00:47 +00:00
parent 68caa7d34d
commit 2e32155b58
15 changed files with 422 additions and 240 deletions
Download Patch File Download Diff File Expand all files Collapse all files

24
clang/lib/Sema/SemaExceptionSpec.cpp
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@@ -720,10 +720,11 @@ static bool CheckSpecForTypesEquivalent(Sema &S,
/// assignment and override compatibility check. We do not check the parameters
/// of parameter function pointers recursively, as no sane programmer would
/// even be able to write such a function type.
bool Sema::CheckParamExceptionSpec(const PartialDiagnostic & NoteID,
const FunctionProtoType *Target, SourceLocation TargetLoc,
const FunctionProtoType *Source, SourceLocation SourceLoc)
{
bool Sema::CheckParamExceptionSpec(const PartialDiagnostic &NoteID,
const FunctionProtoType *Target,
SourceLocation TargetLoc,
const FunctionProtoType *Source,
SourceLocation SourceLoc) {
if (CheckSpecForTypesEquivalent(
*this, PDiag(diag::err_deep_exception_specs_differ) << 0, PDiag(),
Target->getReturnType(), TargetLoc, Source->getReturnType(),
@@ -744,23 +745,30 @@ bool Sema::CheckParamExceptionSpec(const PartialDiagnostic & NoteID,
return false;
}
bool Sema::CheckExceptionSpecCompatibility(Expr *From, QualType ToType)
{
bool Sema::CheckExceptionSpecCompatibility(Expr *From, QualType ToType) {
// First we check for applicability.
// Target type must be a function, function pointer or function reference.
const FunctionProtoType *ToFunc = GetUnderlyingFunction(ToType);
if (!ToFunc)
if (!ToFunc || ToFunc->hasDependentExceptionSpec())
return false;
// SourceType must be a function or function pointer.
const FunctionProtoType *FromFunc = GetUnderlyingFunction(From->getType());
if (!FromFunc)
if (!FromFunc || FromFunc->hasDependentExceptionSpec())
return false;
// Now we've got the correct types on both sides, check their compatibility.
// This means that the source of the conversion can only throw a subset of
// the exceptions of the target, and any exception specs on arguments or
// return types must be equivalent.
//
// FIXME: If there is a nested dependent exception specification, we should
// not be checking it here. This is fine:
// template<typename T> void f() {
// void (*p)(void (*) throw(T));
// void (*q)(void (*) throw(int)) = p;
// }
// ... because it might be instantiated with T=int.
return CheckExceptionSpecSubset(PDiag(diag::err_incompatible_exception_specs),
PDiag(), ToFunc,
From->getSourceRange().getBegin(),