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author | Marek Polacek <polacek@redhat.com> | 2020-02-28 16:57:04 -0500 |
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committer | Marek Polacek <polacek@redhat.com> | 2020-03-09 19:54:51 -0400 |
commit | d417b4f5414d9076300ab41974a14424f722688c (patch) | |
tree | 9a570171945bfd3c01b4eab4a93b2a1c86c2ff46 /gcc/cp/typeck2.c | |
parent | ea182fe63634bb5b7913b3f1b6846e1900c5e0c4 (diff) | |
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c++: Fix convert_like in template [PR91465, PR93870, PR92031, PR94068]
The point of this patch is to fix the recurring problem of trees
generated by convert_like while processing a template that break when
substituting. For instance, when convert_like creates a CALL_EXPR
while in a template, substituting such a call breaks in finish_call_expr
because we have two 'this' arguments. Another problem is that we
can create &TARGET_EXPR<> and then fail when substituting because we're
taking the address of an rvalue. I've analyzed some of the already fixed
PRs and also some of the currently open ones:
In c++/93870 we create EnumWrapper<E>::operator E(&operator~(E)).
In c++/87145 we create S::operator int (&{N}).
In c++/92031 we create &TARGET_EXPR <0>.
The gist of the problem is when convert_like_real creates a call for
a ck_user or wraps a TARGET_EXPR in & in a template. So in these cases
use IMPLICIT_CONV_EXPR. In a template we shouldn't need to perform the
actual conversion, we only need it's result type.
perform_direct_initialization_if_possible and
perform_implicit_conversion_flags can also create an IMPLICIT_CONV_EXPR.
Given the change above, build_converted_constant_expr can return an
IMPLICIT_CONV_EXPR so call fold_non_dependent_expr rather than
maybe_constant_value to deal with that.
To avoid the problem of instantiating something twice in a row I'm
removing a call to instantiate_non_dependent_expr_sfinae in
compute_array_index_type_loc. And the build_converted_constant_expr
pattern can now be simplified.
2020-03-09 Marek Polacek <polacek@redhat.com>
PR c++/92031 - bogus taking address of rvalue error.
PR c++/91465 - ICE with template codes in check_narrowing.
PR c++/93870 - wrong error when converting template non-type arg.
PR c++/94068 - ICE with template codes in check_narrowing.
* call.c (convert_like_real): Return IMPLICIT_CONV_EXPR
in a template when not ck_identity and we're dealing with a class.
(convert_like_real) <case ck_ref_bind>: Return IMPLICIT_CONV_EXPR
in a template if we need a temporary.
* decl.c (compute_array_index_type_loc): Remove
instantiate_non_dependent_expr_sfinae call. Call
fold_non_dependent_expr instead of maybe_constant_value.
(build_explicit_specifier): Don't instantiate or create a sentinel
before converting the expression.
* except.c (build_noexcept_spec): Likewise.
* pt.c (convert_nontype_argument): Don't build IMPLICIT_CONV_EXPR.
Set IMPLICIT_CONV_EXPR_NONTYPE_ARG if that's what
build_converted_constant_expr returned.
* typeck2.c (check_narrowing): Call fold_non_dependent_expr instead
of maybe_constant_value.
* g++.dg/cpp0x/conv-tmpl2.C: New test.
* g++.dg/cpp0x/conv-tmpl3.C: New test.
* g++.dg/cpp0x/conv-tmpl4.C: New test.
* g++.dg/cpp0x/conv-tmpl5.C: New test.
* g++.dg/cpp0x/conv-tmpl6.C: New test.
* g++.dg/cpp1z/conv-tmpl1.C: New test.
Diffstat (limited to 'gcc/cp/typeck2.c')
-rw-r--r-- | gcc/cp/typeck2.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/gcc/cp/typeck2.c b/gcc/cp/typeck2.c index 4892089..bff4ddb 100644 --- a/gcc/cp/typeck2.c +++ b/gcc/cp/typeck2.c @@ -981,7 +981,11 @@ check_narrowing (tree type, tree init, tsubst_flags_t complain, return ok; } - init = maybe_constant_value (init); + /* Even non-dependent expressions can still have template + codes like CAST_EXPR, so use *_non_dependent_expr to cope. */ + init = fold_non_dependent_expr (init, complain); + if (init == error_mark_node) + return ok; /* If we were asked to only check constants, return early. */ if (const_only && !TREE_CONSTANT (init)) |