Re: [PATCH v2] c++: Failure to delay noexcept parsing with ptr-operator [PR100752]

[Marek Polacek <polacek@redhat.com>]

On Thu, Jun 10, 2021 at 10:31:33PM -0400, Jason Merrill wrote:
> On 6/10/21 5:19 PM, Marek Polacek wrote:
> > On Thu, Jun 10, 2021 at 03:09:29PM -0400, Jason Merrill wrote:
> > > On 6/8/21 8:25 PM, Marek Polacek wrote:
> > > > We weren't passing 'flags' to the recursive call to cp_parser_declarator
> > > > in the ptr-operator case and as an effect, delayed parsing of noexcept
> > > > didn't work as advertised.  The following change passes more than just
> > > > CP_PARSER_FLAGS_DELAY_NOEXCEPT but that doesn't seem to break anything.
> > > > 
> > > > I'm not passing member_p because I don't need it and because it breaks
> > > > a few tests.
> > > > 
> > > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/branches?
> > > > 
> > > > 	PR c++/100752
> > > > 
> > > > gcc/cp/ChangeLog:
> > > > 
> > > > 	* parser.c (cp_parser_declarator): Pass flags down to
> > > > 	cp_parser_declarator.
> > > > 
> > > > gcc/testsuite/ChangeLog:
> > > > 
> > > > 	* g++.dg/cpp0x/noexcept69.C: New test.
> > > > ---
> > > >    gcc/cp/parser.c                         |  3 +--
> > > >    gcc/testsuite/g++.dg/cpp0x/noexcept69.C | 12 ++++++++++++
> > > >    2 files changed, 13 insertions(+), 2 deletions(-)
> > > >    create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept69.C
> > > > 
> > > > diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
> > > > index d59a829d0b9..5930990ec1c 100644
> > > > --- a/gcc/cp/parser.c
> > > > +++ b/gcc/cp/parser.c
> > > > @@ -22066,8 +22066,7 @@ cp_parser_declarator (cp_parser* parser,
> > > >    	cp_parser_parse_tentatively (parser);
> > > >          /* Parse the dependent declarator.  */
> > > > -      declarator = cp_parser_declarator (parser, dcl_kind,
> > > > -					 CP_PARSER_FLAGS_NONE,
> > > > +      declarator = cp_parser_declarator (parser, dcl_kind, flags,
> > > >    					 /*ctor_dtor_or_conv_p=*/NULL,
> > > >    					 /*parenthesized_p=*/NULL,
> > > >    					 /*member_p=*/false,
> > > 
> > > Should the other parameters also be passed down?  I'd think definitely
> > > member_p and static_p, not sure about ctor_dtor_or_conv_p and
> > > parenthesized_p.
> > 
> > Hmm, as I mentioned in the patch description, I tried, but passing member_p
> > broke a few tests and since it's not needed for this fix I gave up
> > investigating why.  I could look into it if you're curious :).
> 
> Please.

Turns out those were just trivial changes to the expected error messages.
The following patch passes member_p and static_p too:

Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

-- >8 --
We weren't passing 'flags' to the recursive call to cp_parser_declarator
in the ptr-operator case and as an effect, delayed parsing of noexcept
didn't work as advertised.  The following change passes more than just
CP_PARSER_FLAGS_DELAY_NOEXCEPT but that doesn't seem to break anything.

I'm now also passing member_p and static_p, as a consequence, two tests
needed small tweaks.

	PR c++/100752

gcc/cp/ChangeLog:

	* parser.c (cp_parser_declarator): Pass flags down to
	cp_parser_declarator.  Also pass static_p/member_p.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/noexcept69.C: New test.
	* g++.dg/parse/saved1.C: Adjust dg-error.
	* g++.dg/template/crash50.C: Likewise.
---
 gcc/cp/parser.c                         |  6 ++----
 gcc/testsuite/g++.dg/cpp0x/noexcept69.C | 12 ++++++++++++
 gcc/testsuite/g++.dg/parse/saved1.C     |  4 ++--
 gcc/testsuite/g++.dg/template/crash50.C |  2 +-
 4 files changed, 17 insertions(+), 7 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept69.C

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 096580e7e50..02daa7a6f6a 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -22170,12 +22170,10 @@ cp_parser_declarator (cp_parser* parser,
 	cp_parser_parse_tentatively (parser);
 
       /* Parse the dependent declarator.  */
-      declarator = cp_parser_declarator (parser, dcl_kind,
-					 CP_PARSER_FLAGS_NONE,
+      declarator = cp_parser_declarator (parser, dcl_kind, flags,
 					 /*ctor_dtor_or_conv_p=*/NULL,
 					 /*parenthesized_p=*/NULL,
-					 /*member_p=*/false,
-					 friend_p, /*static_p=*/false);
+					 member_p, friend_p, static_p);
 
       /* If we are parsing an abstract-declarator, we must handle the
 	 case where the dependent declarator is absent.  */
diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept69.C b/gcc/testsuite/g++.dg/cpp0x/noexcept69.C
new file mode 100644
index 00000000000..9b87ba0cafb
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/noexcept69.C
@@ -0,0 +1,12 @@
+// PR c++/100752
+// { dg-do compile { target c++11 } }
+
+struct S {
+  void f() noexcept {}
+  S &g() noexcept(noexcept(f())) { f(); return *this; }
+};
+
+struct X {
+  int& f() noexcept(noexcept(i));
+  int i;
+};
diff --git a/gcc/testsuite/g++.dg/parse/saved1.C b/gcc/testsuite/g++.dg/parse/saved1.C
index 979a05676d2..1deaa93f516 100644
--- a/gcc/testsuite/g++.dg/parse/saved1.C
+++ b/gcc/testsuite/g++.dg/parse/saved1.C
@@ -1,7 +1,7 @@
 // Test that the parser doesn't go into an infinite loop from ignoring the
 // PRE_PARSED_FUNCTION_DECL token.
 
-class C { static void* operator new(size_t); }; // { dg-error "24:declaration of .operator new. as non-function" }
-// { dg-error "expected|ISO C\\+\\+ forbids" "" { target *-*-* } .-1 }
+class C { static void* operator new(size_t); }; // { dg-error "37:.size_t. has not been declared" }
+// { dg-error ".operator new. takes type .size_t." "" { target *-*-* } .-1 }
 void* C::operator new(size_t) { return 0; } // { dg-error "" }
 class D { D(int i): integer(i){}}; // { dg-error "" }
diff --git a/gcc/testsuite/g++.dg/template/crash50.C b/gcc/testsuite/g++.dg/template/crash50.C
index 286685ac838..4b846cdabc8 100644
--- a/gcc/testsuite/g++.dg/template/crash50.C
+++ b/gcc/testsuite/g++.dg/template/crash50.C
@@ -3,5 +3,5 @@
 
 struct A
 {
-  template<int> void* foo(; // { dg-error "primary-expression|initialization|static|template" }
+  template<int> void* foo(; // { dg-error "expected|initialization|static|template" }
 };

base-commit: 74ebd1297e9cfa9f7d05bfcac5510d4968cc6ba8
-- 
2.31.1