| Message ID | 20200514201927.3787724-1-ppalka@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | c++: decltype of invalid non-dependent expr [PR57943] | expand |
On 5/14/20 4:19 PM, Patrick Palka wrote: > We sometimes fail to reject a invalid non-dependent operand to decltype > when inside a template, because finish_decltype_type resolves the > decltype to the TREE_TYPE of the operand before we ever instantiate and > fully process the operand. Fix this by adding a call to > instantiate_non_dependent_expr_sfinae in finish_decltype_type. > > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK to > commit? OK. > gcc/cp/ChangeLog: > > PR c++/57943 > * semantics.c (finish_decltype_type): Call > instantiate_non_dependent_expr_sfinae on the decltype's operand. > > gcc/testsuite/ChangeLog: > > PR c++/57943 > * g++.dg/cpp0x/decltype76.C: New test. > --- > gcc/cp/semantics.c | 8 ++++++++ > gcc/testsuite/g++.dg/cpp0x/decltype76.C | 7 +++++++ > 2 files changed, 15 insertions(+) > create mode 100644 gcc/testsuite/g++.dg/cpp0x/decltype76.C > > diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c > index d90816eabc9..64587c791c6 100644 > --- a/gcc/cp/semantics.c > +++ b/gcc/cp/semantics.c > @@ -9746,6 +9746,14 @@ finish_decltype_type (tree expr, bool id_expression_or_member_access_p, > > return type; > } > + else if (processing_template_decl) > + { > + ++cp_unevaluated_operand; > + expr = instantiate_non_dependent_expr_sfinae (expr, complain); > + --cp_unevaluated_operand; > + if (expr == error_mark_node) > + return error_mark_node; > + } > > /* The type denoted by decltype(e) is defined as follows: */ > > diff --git a/gcc/testsuite/g++.dg/cpp0x/decltype76.C b/gcc/testsuite/g++.dg/cpp0x/decltype76.C > new file mode 100644 > index 00000000000..239fe6d2a8f > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp0x/decltype76.C > @@ -0,0 +1,7 @@ > +// PR c+/57943 > +// { dg-do compile { target c++11 } } > + > +struct a { }; > + > +template <typename T = decltype (a(0))> // { dg-error "" } > +void f() { } >
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c index d90816eabc9..64587c791c6 100644 --- a/gcc/cp/semantics.c +++ b/gcc/cp/semantics.c @@ -9746,6 +9746,14 @@ finish_decltype_type (tree expr, bool id_expression_or_member_access_p, return type; } + else if (processing_template_decl) + { + ++cp_unevaluated_operand; + expr = instantiate_non_dependent_expr_sfinae (expr, complain); + --cp_unevaluated_operand; + if (expr == error_mark_node) + return error_mark_node; + } /* The type denoted by decltype(e) is defined as follows: */ diff --git a/gcc/testsuite/g++.dg/cpp0x/decltype76.C b/gcc/testsuite/g++.dg/cpp0x/decltype76.C new file mode 100644 index 00000000000..239fe6d2a8f --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/decltype76.C @@ -0,0 +1,7 @@ +// PR c+/57943 +// { dg-do compile { target c++11 } } + +struct a { }; + +template <typename T = decltype (a(0))> // { dg-error "" } +void f() { }