1) Declaration of function parameter packs
2) Instantiation of function parameter packs within function types.
3) Template argument deduction of function parameter packs when
matching two function types.
We're missing all of the important template-instantiation logic for
function template definitions, along with template argument deduction
from the argument list of a function call, so don't even think of
trying to use these for real yet.
llvm-svn: 122926
expansions with something that is easier to use correctly: a new
template argment kind, rather than a bit on an existing kind. Update
all of the switch statements that deal with template arguments, fixing
a few latent bugs in the process. I"m happy with this representation,
now.
And, oh look! Template instantiation and deduction work for template
template argument pack expansions.
llvm-svn: 122896
for template template argument pack expansions. This allows fun such
as:
template<template<class> class ...> struct apply_impl { /*...*/ };
template<template<class> class ...Metafunctions> struct apply {
typedef typename apply_impl<Metafunctions...>::type type;
};
However, neither template argument deduction nor template
instantiation is implemented for template template argument packs, so
this functionality isn't useful yet.
I'll probably replace the encoding of template template
argument pack expansions in TemplateArgument so that it's harder to
accidentally forget about the expansion. However, this is a step in
the right general direction.
llvm-svn: 122890
conversions on the substituted non-type template arguments of a class
template partial specialization. C++ [temp.class.spec]p8 actually
prohibits all of the cases where this code would have fired.
Hey, it's better than having to deal with variadic templates here!
llvm-svn: 122852
specializations. We weren't dealing with any of the cases where the
type of the non-type template argument differs from the type of the
corresponding template parameter in the primary template. We would
think that the template parameter in the partial specialization was
not deducible (and warn about it, incorrectly), then fail to convert a
deduced parameter to the type of the template parameter in the partial
specialization (which may involve truncation, among other
things). Fixes PR8905.
llvm-svn: 122851
template argument (described by an expression, of course). For
example:
template<int...> struct int_tuple { };
template<int ...Values>
struct square {
typedef int_tuple<(Values*Values)...> type;
};
It also lays the foundation for pack expansions in an initializer-list.
llvm-svn: 122751
caused an assertion when dealing with non-type template parameter
packs. Add some tests for deduction and instantiation of non-type
template parameter packs.
llvm-svn: 122534
parameter packs. In particular, a parameter pack not otherwise deduced
is deduced to an empty parameter pack.
The C++0x wording here is a bit unfortunate; this should really only
apply to function templates, and it mentions "trailing" parameter
packs, which doesn't really make sense in the context of function
templates. Will file a core issue separately.
llvm-svn: 122463
the presence of a pack expansion anywhere except at the end of a
template-argument-list causes the entire template-argument-list to be
a non-deduced context.
llvm-svn: 122461
single routine. Extend that routine to handle consistency
checking for template argument packs, so that we can compare the
deduced packs for template parameter packs across different pack
expansions.
llvm-svn: 122452
pattern is a template argument, which involves repeatedly deducing
template arguments using the pattern of the pack expansion, then
bundling the resulting deductions into an argument pack.
We can now handle a variety of simple list-handling metaprograms using
variadic templates. See, e.g., the new "count" metaprogram.
llvm-svn: 122439
dependent template specialization type, the number of template
arguments need not match precisely. Rather than checking the number of
arguments eagerly (which does not consider argument packs), let the
deduction routine for template argument lists cope with too many/too
few arguments.
llvm-svn: 122425
deduction. Unify all of the looping over template arguments for
deduction purposes into a single place, where argument pack expansion
occurs; this is also the hook for deducing from pack expansions, which
itself is not yet implemented.
For now, at least we can handle a basic "count" metafunction written
with variadics. See the new test for the formulation that works.
llvm-svn: 122418
area of printing template arguments. The functionality changes here
are limited to cases of variadic templates that aren't yet enabled.
llvm-svn: 122250
pack expansions, e.g. given
template<typename... Types> struct tuple;
template<typename... Types>
struct tuple_of_refs {
typedef tuple<Types&...> types;
};
the type of the "types" typedef is a PackExpansionType whose pattern
is Types&.
This commit introduces support for creating pack expansions for
template type arguments, as above, but not for any other kind of pack
expansion, nor for any form of instantiation.
llvm-svn: 122223
space better. Remove this reference. To make that work, change some APIs
(most importantly, getDesugaredType()) to take an ASTContext& if they
need to return a QualType. Simultaneously, diminish the need to return a
QualType by introducing some useful APIs on SplitQualType, which is
just a std::pair<const Type *, Qualifiers>.
llvm-svn: 121478
zextOrTrunc(), and APSInt methods extend(), extOrTrunc() and new method
trunc(), to be const and to return a new value instead of modifying the
object in place.
llvm-svn: 121121
particular, we only add the implement object parameter type if only
one of the function templates is a non-static member function
template.
Moreover, since this DR differs from existing practice in C++98/03,
this commit implements the existing practice (which ignores the
first parameter of the function template that is not the non-static
member function template) in C++98/03 mode.
llvm-svn: 119145
abstractions (e.g., TemplateArgumentListBuilder) that were designed to
support variadic templates. Only a few remnants of variadic templates
remain, in the parser (parsing template type parameter packs), AST
(template type parameter pack bits and TemplateArgument::Pack), and
Sema; these are expected to be used in a future implementation of
variadic templates.
But don't get too excited about that happening now.
llvm-svn: 118385
only keep deduction results for successful deductions, so that they
can be compared against each other. Fixes PR8462, from Richard Smith!
llvm-svn: 117983
that are suppressed during template argument deduction. This change
queues diagnostics computed during template argument deduction. Then,
if the resulting function template specialization or partial
specialization is chosen by overload resolution or partial ordering
(respectively), we will emit the queued diagnostics at that point.
This addresses most of PR6784. However, the check for unnamed/local
template arguments (which existed before this change) is still only
skin-deep, and needs to be extended to look deeper into types. It must
be improved to finish PR6784.
llvm-svn: 116373
argument deduction, make sure to check the correctness of deduced template
type arguments (which we had previously skipped) along with other
kinds of template arguments. This fixes part of PR6784, but we're
still swallowing the extension warning about unnamed/local template
arguments.
llvm-svn: 116327
against a function type, be sure to check the type of the resulting
function template specialization against the desired function type
after substituting the deduced/defaulted template arguments. Fixes PR8196.
llvm-svn: 115086
deduction where the parameter is a function reference, function
pointer, or member function pointer and the argument is an overloaded
function. Fixes <rdar://problem/8360106>, a template argument
deduction issue found by Boost.Filesystem.
llvm-svn: 112523
an '&' expression from the second caller of ActOnIdExpression.
Teach template argument deduction that an overloaded id-expression
doesn't give a valid type for deduction purposes to a non-static
member function unless the expression has the correct syntactic
form.
Teach ActOnIdExpression that it shouldn't try to create implicit
member expressions for '&function', because this isn't a
permitted form of use for member functions.
Teach CheckAddressOfOperand to diagnose these more carefully.
Some of these cases aren't reachable right now because earlier
diagnostics interrupt them.
llvm-svn: 112258
- move DeclSpec &c into the Sema library
- move ParseAST into the Parse library
Reflect this change in a thousand different includes.
Reflect this change in the link orders.
llvm-svn: 111667
a template-argument-list. When template template parameters are
involved, we won't already have checked the template-argument-list (it
may not be known yet!). Fixes PR7807.
llvm-svn: 110444
case of an elaborated-type-specifier like 'typename A<T>::foo', and
DependentTemplateSpecializationType represents the case of an
elaborated-type-specifier like 'typename A<T>::template B<T>'. The TypeLoc
representation of a DependentTST conveniently exactly matches that of an
ElaboratedType wrapping a TST.
Kill off the explicit rebuild methods for RebuildInCurrentInstantiation;
the standard implementations work fine because the nested name specifier
is computable in the newly-entered context.
llvm-svn: 105801
ObjCObjectType, which is basically just a pair of
one of {primitive-id, primitive-Class, user-defined @class}
with
a list of protocols.
An ObjCObjectPointerType is therefore just a pointer which always points to
one of these types (possibly sugared). ObjCInterfaceType is now just a kind
of ObjCObjectType which happens to not carry any protocols.
Alter a rather large number of use sites to use ObjCObjectType instead of
ObjCInterfaceType. Store an ObjCInterfaceType as a pointer on the decl rather
than hashing them in a FoldingSet. Remove some number of methods that are no
longer used, at least after this patch.
By simplifying ObjCObjectPointerType, we are now able to easily remove and apply
pointers to Objective-C types, which is crucial for a certain kind of ObjC++
metaprogramming common in WebKit.
llvm-svn: 103870
specific message that includes the template arguments, e.g.,
test/SemaTemplate/overload-candidates.cpp:27:20: note: candidate template
ignored: substitution failure [with T = int *]
typename T::type get_type(const T&); // expected-note{{candidate ...
^
llvm-svn: 103348
specializations, substitute the deduced template arguments and check
the resulting substitution before concluding that template argument
deduction succeeds. This marvelous little fix makes a bunch of
Boost.Spirit tests start working.
llvm-svn: 102601
template argument deduction or (more importantly) the final substitution
required by such deduction. Makes access control magically work in these
cases.
Fixes PR6967.
llvm-svn: 102572
template argument deduction, use the lexical declaration context as
the owner for friend function templates. Fixes 2 failures in
Boost.Graph.
llvm-svn: 102489
of a class template or class template partial specialization. That is to
say, in
template <class T> class A { ... };
or
template <class T> class B<const T*> { ... };
make 'A<T>' and 'B<const T*>' sugar for the corresponding InjectedClassNameType
when written inside the appropriate context. This allows us to track the
current instantiation appropriately even inside AST routines. It also allows
us to compute a DeclContext for a type much more efficiently, at some extra
cost every time we write a template specialization (which can be optimized,
but I've left it simple in this patch).
llvm-svn: 102407
check deduced non-type template arguments and template template
arguments against the template parameters for which they were deduced,
performing conversions as appropriate so that deduced template
arguments get the same treatment as explicitly-specified template
arguments. This is the bulk of PR6723.
Also keep track of whether deduction of a non-type template argument
came from an array bound (vs. anywhere else). With this information,
we enforce C++ [temp.deduct.type]p17, which requires exact type
matches when deduction deduces a non-type template argument from
something that is not an array bound.
Finally, when in a SFINAE context, translate the "zero sized
arrays are an extension" extension diagnostic into a hard error (for
better standard conformance), which was a minor part of PR6723.
llvm-svn: 99734
parameter, keep the integral value exactly as it was in the source
code rather than trying to convert it to the type of the non-type
template parameter (which may still be dependent!). The value will
then be converted to the appropriate type once we check the resulting
template arguments. Fixes PR6707.
llvm-svn: 99611
- When substituting template arguments as part of template argument
deduction, introduce a new local instantiation scope.
- When substituting into a function prototype type, introduce a new
"temporary" local instantiation scope that merges with its outer
scope but also keeps track of any additions it makes, removing
them when we exit that scope.
Fixes PR6700, where we were getting too much mixing of local
instantiation scopes due to template argument deduction that
substituted results into function types.
llvm-svn: 99509
injected class name of a class template or class template partial specialization.
This is a non-canonical type; the canonical type is still a template
specialization type. This becomes the TypeForDecl of the pattern declaration,
which cleans up some amount of code (and complicates some other parts, but
whatever).
Fixes PR6326 and probably a few others, primarily by re-establishing a few
invariants about TypeLoc sizes.
llvm-svn: 98134
category. Use this in a few places to eliminate unnecessary TST cases and
do some future-proofing. Provide terrible manglings for typeof. Mangle
decltype with some hope of accuracy.
Our manglings for some of the cases covered in the testcase are different
from gcc's, which I've raised as an issue with the ABI list.
llvm-svn: 97523
deduction. This requires refactoring the deduction to have access to the Sema
object instead of merely the ASTContext. Still leaves something to be desired
due to poor source location.
Fixes PR6257 and half of PR6259.
llvm-svn: 95528
arguments. Fix a bug where incomplete explicit specializations were being
passed through as legitimate. Fix a bug where the absence of an explicit
specialization in an overload set was causing overall deduction to fail.
Fixes PR6191.
llvm-svn: 95052
(C++ [temp.mem]p5-6), which involves template argument deduction based
on the type named, e.g., given
struct X { template<typename T> operator T*(); } x;
when we call
x.operator int*();
we perform template argument deduction to determine that T=int. This
template argument deduction is needed for template specialization and
explicit instantiation, e.g.,
template<> X::operator float*() { /* ... */ }
and when calling or otherwise naming a conversion function (as in the
first example).
This fixes PR5742 and PR5762, although there's some remaining ugliness
that's causing out-of-line definitions of conversion function
templates to fail. I'll look into that separately.
llvm-svn: 93162
QualType to get CVR-qualifiers through array types, and switches the primary
comparison methods to use it. This may allow simplifying some of the callers of
getUnqualifiedArrayType.
Also fix the normalizing of CV-qualification during template deduction to
normalize through arrays and allow a more qualified deduced array type. This
fixes PR5911.
llvm-svn: 92289
more or less cv-qualified than another during implicit conversion and overload
resolution ([basic.type.qualifier] p5). Factors the logic out of template
deduction and into the ASTContext so it can be shared.
This fixes several aspects of PR5542, but not all of them.
llvm-svn: 92248
explicitly-specified template arguments are enough to determine the
instantiation, and either template argument deduction fails or is not
performed in that context, we can resolve the template-id down to a
function template specialization (so sayeth C++0x
[temp.arg.explicit]p3). Fixes PR5811.
llvm-svn: 91852
not deduce an "overload" type. Such a deduction indicates a failure in
semantic analysis (e.g., PR5811) that currently isn't caught until
code-generation time. This assertions makes it clearer that this
particular issue is a semantic-analysis problem, not a code-gen problem.
llvm-svn: 91844
sugared types. The basic problem is that our qualifier accessors
(getQualifiers, getCVRQualifiers, isConstQualified, etc.) only look at
the current QualType and not at any qualifiers that come from sugared
types, meaning that we won't see these qualifiers through, e.g.,
typedefs:
typedef const int CInt;
typedef CInt Self;
Self.isConstQualified() currently returns false!
Various bugs (e.g., PR5383) have cropped up all over the front end due
to such problems. I'm addressing this problem by splitting each
qualifier accessor into two versions:
- the "local" version only returns qualifiers on this particular
QualType instance
- the "normal" version that will eventually combine qualifiers from this
QualType instance with the qualifiers on the canonical type to
produce the full set of qualifiers.
This commit adds the local versions and switches a few callers from
the "normal" version (e.g., isConstQualified) over to the "local"
version (e.g., isLocalConstQualified) when that is the right thing to
do, e.g., because we're printing or serializing the qualifiers. Also,
switch a bunch of
Context.getCanonicalType(T1).getUnqualifiedType() == Context.getCanonicalType(T2).getQualifiedType()
expressions over to
Context.hasSameUnqualifiedType(T1, T2)
llvm-svn: 88969
permits, among other things, ripping apart and reconstructing
templates via partial specialization:
template<typename T>
struct DeepRemoveConst { typedef T type; };
template<typename T>
struct DeepRemoveConst<const T> {
typedef typename DeepRemoveConst<T>::type type;
};
template<template<typename> class TT, typename T>
struct DeepRemoveConst<TT<T> > {
typedef TT<typename DeepRemoveConst<T>::type> type;
};
Also, fix a longstanding thinko in the code handling partial ordering
of class template partial specializations. We were performing the
second deduction without clearing out the results of the first
deduction. It's amazing we got through so much code with such a
horrendous error :(
llvm-svn: 86893
parameters. Rather than storing them as either declarations (for the
non-dependent case) or expressions (for the dependent case), we now
(always) store them as TemplateNames.
The primary change here is to add a new kind of TemplateArgument,
which stores a TemplateName. However, making that change ripples to
every switch on a TemplateArgument's kind, also affecting
TemplateArgumentLocInfo/TemplateArgumentLoc, default template
arguments for template template parameters, type-checking of template
template arguments, etc.
This change is light on testing. It should fix several pre-existing
problems with template template parameters, such as:
- the inability to use dependent template names as template template
arguments
- template template parameter default arguments cannot be
instantiation
However, there are enough pieces missing that more implementation is
required before we can adequately test template template parameters.
llvm-svn: 86777
types. Preserve it through template instantiation. Preserve it through PCH,
although TSTs themselves aren't serializable, so that's pretty much meaningless.
llvm-svn: 85500
class template partial specializations of member templates. Also,
fixes a silly little bug in the marking of "used" template parameters
in member templates. Fixes PR5236.
llvm-svn: 85447
type is a template-id (e.g., basic_ostream<CharT, Traits>) and the
argument type is a class that has a derived class matching the
parameter type. Previously, we were giving up on template argument
deduction too early.
llvm-svn: 83177
member functions of class template specializations, and static data
members. The mechanics are (mostly) present, but the semantic analysis
is very weak.
llvm-svn: 82789
first implementation recognizes when a function declaration is an
explicit function template specialization (based on the presence of a
template<> header), performs template argument deduction + ambiguity
resolution to determine which template is being specialized, and hooks
There are many caveats here:
- We completely and totally drop any explicitly-specified template
arguments on the floor
- We don't diagnose any of the extra semantic things that we should
diagnose.
- I haven't looked to see that we're getting the right linkage for
explicit specializations
On a happy note, this silences a bunch of errors that show up in
libstdc++'s <iostream>, although Clang still can't get through the
entire header.
llvm-svn: 82728
Type hierarchy. Demote 'volatile' to extended-qualifier status. Audit our
use of qualifiers and fix a few places that weren't dealing with qualifiers
quite right; many more remain.
llvm-svn: 82705
Several of the existing methods were identical to their respective
specializations, and so have been removed entirely. Several more 'leaf'
optimizations were introduced.
The getAsFoo() methods which imposed extra conditions, like
getAsObjCInterfacePointerType(), have been left in place.
llvm-svn: 82501
template smarter, by taking into account which function template
parameters are deducible from the call arguments. For example,
template<typename RandomAccessIterator>
void sort(RandomAccessIterator first, RandomAccessIterator last);
will have a code-completion string like
sort({RandomAccessIterator first}, {RandomAccessIterator last})
since the template argument for its template parameter is
deducible. On the other hand,
template<class X, class Y>
X* dyn_cast(Y *Val);
will have a code-completion string like
dyn_cast<{class X}>({Y *Val})
since the template type parameter X is not deducible from the function
call.
llvm-svn: 82306
MarkUsedTemplateParameters, which is able to mark template parameters
used within non-deduced contexts as well as deduced contexts. Use this
to finish the implementation of [temp.deduct.partial]p11.
llvm-svn: 81794
argument deduction. This fixes the new test case (since partial
ordering does not have a "verify the results of deduction" step), and
will allow failed template argument deductions to return more quickly
for, e.g., matching class template partial specializations.
llvm-svn: 81779
to a multi-level template argument list by making it explicit. The
forced auditing of callers found a bug in the instantiation of member
classes inside member templates.
I *love* static type systems.
llvm-svn: 80391
Type::getAsReferenceType() -> Type::getAs<ReferenceType>()
Type::getAsRecordType() -> Type::getAs<RecordType>()
Type::getAsPointerType() -> Type::getAs<PointerType>()
Type::getAsBlockPointerType() -> Type::getAs<BlockPointerType>()
Type::getAsLValueReferenceType() -> Type::getAs<LValueReferenceType>()
Type::getAsRValueReferenceType() -> Type::getAs<RValueReferenceType>()
Type::getAsMemberPointerType() -> Type::getAs<MemberPointerType>()
Type::getAsReferenceType() -> Type::getAs<ReferenceType>()
Type::getAsTagType() -> Type::getAs<TagType>()
And remove Type::getAsReferenceType(), etc.
This change is similar to one I made a couple weeks ago, but that was partly
reverted pending some additional design discussion. With Doug's pending smart
pointer changes for Types, it seemed natural to take this approach.
llvm-svn: 77510
real. It turns out that we need to actually move all of the qualifiers
up to the array type itself, then recanonicalize the deduced template
argument type.
llvm-svn: 76788
until Doug Gregor's Type smart pointer code lands (or more discussion occurs).
These methods just call the new Type::getAs<XXX> methods, so we still have
reduced implementation redundancy. Having explicit getAsXXXType() methods makes
it easier to set breakpoints in the debugger.
llvm-svn: 76193
This method is intended to eventually replace the individual
Type::getAsXXXType<> methods.
The motivation behind this change is twofold:
1) Reduce redundant implementations of Type::getAsXXXType() methods. Most of
them are basically copy-and-paste.
2) By centralizing the implementation of the getAs<Type> logic we can more
smoothly move over to Doug Gregor's proposed canonical type smart pointer
scheme.
Along with this patch:
a) Removed 'Type::getAsPointerType()'; now clients use getAs<PointerType>.
b) Removed 'Type::getAsBlockPointerTypE()'; now clients use getAs<BlockPointerType>.
llvm-svn: 76098
function template. Most of the change here is in factoring out the
common bits used for template argument deduction from a function call
and when taking the address of a function template.
llvm-svn: 75044
implement C++ [temp.deduct.call]p3b3, which allows a template-id
parameter to match a derived class of the argument, while deducing
template arguments.
llvm-svn: 74965
by distinguishing between substitution that occurs for template
argument deduction vs. explicitly-specifiad template arguments. This
is used both to improve diagnostics and to make sure we only provide
SFINAE in those cases where SFINAE should apply.
In addition, deal with the sticky issue where SFINAE only considers
substitution of template arguments into the *type* of a function
template; we need to issue hard errors beyond this point, as
test/SemaTemplate/operator-template.cpp illustrates.
llvm-svn: 74651
substitute those template arguments into the function parameter types
prior to template argument deduction. There's still a bit of work to
do to make this work properly when only some of the template arguments
are specified.
llvm-svn: 74576
deduction from pointer and pointer-to-member types to work even in the
presence of a qualification conversion (C++ [temp.deduct.type]p3
bullet 2).
llvm-svn: 74354
non-dependent parameter types. Instead, class template partial
specializations perform a final check of all of the instantiated
arguments. This model is cleaner, and works better for function
templates where the "final check" occurs during overload resolution.
Also, cope with cv-qualifiers when the parameter type was originally a
reference type, so that the deduced argument can be more qualified
than the transformed argument.
llvm-svn: 74323
For a FunctionDecl that has been instantiated due to template argument
deduction, we now store the primary template from which it was
instantiated and the deduced template arguments. From this
information, we can instantiate the body of the function template.
llvm-svn: 74232
templates.
For example, this now type-checks (but does not instantiate the body
of deref<int>):
template<typename T> T& deref(T* t) { return *t; }
void test(int *ip) {
int &ir = deref(ip);
}
Specific changes/additions:
* Template argument deduction from a call to a function template.
* Instantiation of a function template specializations (just the
declarations) from the template arguments deduced from a call.
* FunctionTemplateDecls are stored directly in declaration contexts
and found via name lookup (all forms), rather than finding the
FunctionDecl and then realizing it is a template. This is
responsible for most of the churn, since some of the core
declaration matching and lookup code assumes that all functions are
FunctionDecls.
llvm-svn: 74213
Add a type (ObjCObjectPointerType) and remove a type (ObjCQualifiedIdType).
This large/tedious patch is just a first step. Next step is to remove ObjCQualifiedInterfaceType. After that, I will remove the magic TypedefType for 'id' (installed by Sema). This work will enable various simplifications throughout clang (when dealing with ObjC types).
No functionality change.
llvm-svn: 73649
that were suppressed due to SFINAE. By checking whether any errors
occur at the end of template argument deduction, we avoid the
possibility of suppressing an error (due to SFINAE) and then
recovering so well that template argument deduction never detects that
there was a problem. Thanks to Eli for the push in this direction.
llvm-svn: 73336
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
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
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
- Once we have deduced template arguments for a class template partial
specialization, we use exactly those template arguments for instantiating
the definition of the class template partial specialization.
- Added template argument deduction for non-type template parameters.
- Added template argument deduction for dependently-sized array types.
With these changes, we can now implement, e.g., the remove_reference
type trait. Also, Daniel's Ackermann template metaprogram now compiles
properly.
llvm-svn: 72909
deductions of the same template parameter are equivalent. This allows
us to implement the is_same type trait (!).
Also, move template argument deduction into its own file and update a
few build systems with this change (grrrr).
llvm-svn: 72819
Douglas Gregor