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pt.c (maybe_adjust_types_for_deduction, [...]): Remove spurious information in comment.

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cp:
	* pt.c (maybe_adjust_types_for_deduction, DEDUCE_ORDER case):
	Remove spurious information in comment. Allow further
	adjustments of REFERENCE_TYPE args.
testsuite:
	* g++.old-deja/g++.pt/spec40.C: New test.

From-SVN: r39604
This commit is contained in:
Nathan Sidwell 2001-02-12 14:38:25 +00:00 • committed by Nathan Sidwell
parent 82c18d5c67
commit 996065b440
4 changed files with 27 additions and 18 deletions
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6
gcc/cp/ChangeLog
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@ -1,3 +1,9 @@
2001-02-12 Nathan Sidwell <nathan@codesourcery.com>
* pt.c (maybe_adjust_types_for_deduction, DEDUCE_ORDER case):
Remove spurious information in comment. Allow further
adjustments of REFERENCE_TYPE args.
2001-02-12 Nathan Sidwell <nathan@codesourcery.com>
* errfn.c (cp_deprecated): Tweak diagnostic text.

22
gcc/cp/pt.c
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@ -7833,31 +7833,18 @@ maybe_adjust_types_for_deduction (strict, parm, arg)
compiler accepts it).
John also confirms that deduction should proceed as in a function
call. Which implies the usual ARG and PARM bashing as DEDUCE_CALL.
call. Which implies the usual ARG and PARM conversions as DEDUCE_CALL.
However, in ordering, ARG can have REFERENCE_TYPE, but no argument
to an actual call can have such a type.
When deducing against a REFERENCE_TYPE, we can either not change
PARM's type, or we can change ARG's type too. The latter, though
seemingly more safe, turns out to give the following quirk. Consider
deducing a call to a `const int *' with the following template
function parameters
#1; T const *const & ; T = int
#2; T *const & ; T = const int
#3; T * ; T = const int
It looks like #1 is the more specialized. Taken pairwise, #1 is
more specialized than #2 and #2 is more specialized than #3, yet
there is no ordering between #1 and #3.
So, if ARG is a reference, we look though it when PARM is
not a refence. When both are references we don't change either. */
If both ARG and PARM are REFERENCE_TYPE, we change neither.
If only ARG is a REFERENCE_TYPE, we look through that and then
proceed as with DEDUCE_CALL (which could further convert it). */
if (TREE_CODE (*arg) == REFERENCE_TYPE)
{
if (TREE_CODE (*parm) == REFERENCE_TYPE)
return 0;
*arg = TREE_TYPE (*arg);
result |= UNIFY_ALLOW_OUTER_LESS_CV_QUAL;
goto skip_arg;
}
break;
default:
@ -7890,7 +7877,6 @@ maybe_adjust_types_for_deduction (strict, parm, arg)
*arg = TYPE_MAIN_VARIANT (*arg);
}
skip_arg:;
/* [temp.deduct.call]
If P is a cv-qualified type, the top level cv-qualifiers

4
gcc/testsuite/ChangeLog
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@ -1,3 +1,7 @@
2001-02-12 Nathan Sidwell <nathan@codesourcery.com>
* g++.old-deja/g++.pt/spec40.C: New test.
2001-02-12 Nathan Sidwell <nathan@codesourcery.com>
* g++.old-deja/g++.robertl/eb63.C: Remove new initializer list

13
gcc/testsuite/g++.old-deja/g++.pt/spec40.C Normal file
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@ -0,0 +1,13 @@
// Copyright (C) 2000 Free Software Foundation, Inc.
// Contributed by Nathan Sidwell 12 Feb 2001 <nathan@codesourcery.com>
// More from bug 1617. We didn't resolve partial ordering properly. The
// std is rather vague about it anyway, DR 214 talks about this.
template <typename T> int Foo (T const *) {return 1;}
template <unsigned I> int Foo (char const (&)[I]) {return 2;}
int main ()
{
return Foo ("a") != 2;
}