Implement support for C++ Substitution Failure Is Not An Error
(SFINAE), which says that errors that occur during template argument
deduction do *not* produce diagnostics and do not necessarily make a
program ill-formed. Instead, template argument deduction silently
fails. This is currently implemented for template argument deduction
during matching of class template partial specializations, although
the mechanism will also apply to template argument deduction for
function templates. The scheme is simple:

  - If we are in a template argument deduction context, any diagnostic
    that is considered a SFINAE error (or warning) will be
    suppressed. The error will be propagated up the call stack via the
    normal means.
  - By default, all warnings and errors are SFINAE errors. Add the
    NoSFINAE class to a diagnostic in the .td file to make it a hard
    error (e.g., for access-control violations).

Note that, to make this fully work, every place in Sema that emits an
error *and then immediately recovers* will need to check
Sema::isSFINAEContext() to determine whether it must immediately
return an error rather than recovering.

llvm-svn: 73332

preprocessor and initialize it early in clang-cc.  This
ensures that __has_builtin works in all modes, not just
when ASTContext is around.

llvm-svn: 73319

llvm-svn: 73316

Have CheckClassTemplatePartialSpecializationArgs take a TemplateArgumentListBuilder. No functionality change.

llvm-svn: 73297

of the elements.  Issue reported on cfe-dev by Mattias Holm.

llvm-svn: 73292

I'm not completely sure this is the right way to fix this issue, but it seems 
reasonable, and it's consistent with the non-template code for this 
construct.

llvm-svn: 73285

llvm-svn: 73281

obviously written by someone who didn't read C++ [temp.class.spec].

llvm-svn: 73276

llvm-svn: 73275

specialization cannot be deduced, produce a warning noting that the
affected class template partial specialization will never be used.

llvm-svn: 73274

llvm-svn: 73269

llvm-svn: 73268

This fixes a source range problem reported by Olaf Krzikalla.

llvm-svn: 73266

llvm-svn: 73264

It looks like we've finished off matching of class template partial specializations; add comments and update the C++ status page

llvm-svn: 73263

llvm-svn: 73262

llvm-svn: 73261

llvm-svn: 73260

specialization's arguments are identical to the implicit template
arguments of the primary template. Typically, this is meant to be a
declaration/definition of the primary template, so we give that
advice.

llvm-svn: 73259

template partial specializations.

llvm-svn: 73254

llvm-svn: 73247

specialization do not have default arguments 
(C++ [temp.class.spec]p10). 

llvm-svn: 73245

llvm-svn: 73240

argument deduction failed. For example, given

  template<typename T> struct is_same<T, T> { ... };

template argument deduction will fail for is_same<int, float>, and now
reports enough information

Right now, we don't do anything with this extra information, but it
can be used for informative diagnostics that say, e.g., "template
argument deduction failed because T was deduced to 'int' in one
context and 'float' in another".

llvm-svn: 73237

It's an error to use a function declared in a class definition as a default argument before the function has been declared.

llvm-svn: 73234

llvm-svn: 73232

partial specialization, substitute those template arguments back into
the template arguments of the class template partial specialization to
see if the results still match the original template arguments.

This code is more general than it needs to be, since we don't yet
diagnose C++ [temp.class.spec]p9. However, it's likely to be needed
for function templates.

llvm-svn: 73196

Add a null check that fixes the crash in PR4362, and make sure to instantiate non-type template arguments.

llvm-svn: 73193

(Actually, this isn't precisely correct, but it doesn't make 
sense to query whether an expression that isn't an ICE is 
value-dependent anyway.)

llvm-svn: 73179

llvm-svn: 73176

Also, introduced some of the framework for performing instantiation as
part of template argument deduction.

llvm-svn: 73175

visible anywhere normally because the printf format checks for 
this case, and we don't print out attribute values anywhere.  Original 
patch by Roberto Bagnara.

llvm-svn: 73157

T::*) and implement template instantiation for member pointer types.

llvm-svn: 73151

specialization types. As the example shows, we can now compute the
length of a type-list using a template metaprogram and class template
partial specialization.

llvm-svn: 73136

llvm-svn: 73101

llvm-svn: 73077

llvm-svn: 73071

llvm-svn: 73070

llvm-svn: 73043

hack which introduces some strange inconsistencies in compatibility 
for block pointers.

Note that unlike an earlier revision proposed on cfe-commits, this patch 
still allows declaring block pointers without a prototype.

llvm-svn: 73041