From: Marek Polacek <polacek@redhat.com>
Date: Fri, 8 Jan 2021 20:48:41 +0000 (-0500)
Subject: c++: ICE when late parsing noexcept/NSDMI [PR98333]
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=c37f1d4081f5a19e39192d13e2a3acea13662e5a;p=gcc.git

c++: ICE when late parsing noexcept/NSDMI [PR98333]

Since certain members of a class are a complete-class context
[class.mem.general]p7, we delay their parsing untile the whole class has
been parsed.  For instance, NSDMIs and noexcept-specifiers.  The order
in which we perform this delayed parsing matters; we were first parsing
NSDMIs and only they did we parse noexcept-specifiers.   That turns out
to be wrong: since NSDMIs may use noexcept-specifiers, we must process
noexcept-specifiers first.  Otherwise we'll ICE in code that doesn't
expect to see DEFERRED_PARSE.

This doesn't just shift the problem, noexcept-specifiers can use members
with a NSDMI just fine, and I've also tested a similar test with this
member function:

  bool f() { return __has_nothrow_constructor (S<true>); }

and that compiled fine too.

gcc/cp/ChangeLog:

	PR c++/98333
	* parser.c (cp_parser_class_specifier_1): Perform late-parsing
	of NSDMIs before late-parsing of noexcept-specifiers.

gcc/testsuite/ChangeLog:

	PR c++/98333
	* g++.dg/cpp0x/noexcept62.C: New test.
---

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index e67339d56f9..5651cfacd3c 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -25008,31 +25008,10 @@ cp_parser_class_specifier_1 (cp_parser* parser)
 	  maybe_end_member_template_processing ();
 	}
       vec_safe_truncate (unparsed_funs_with_default_args, 0);
-      /* Now parse any NSDMIs.  */
-      save_ccp = current_class_ptr;
-      save_ccr = current_class_ref;
-      FOR_EACH_VEC_SAFE_ELT (unparsed_nsdmis, ix, decl)
-	{
-	  if (class_type != DECL_CONTEXT (decl))
-	    {
-	      if (pushed_scope)
-		pop_scope (pushed_scope);
-	      class_type = DECL_CONTEXT (decl);
-	      pushed_scope = push_scope (class_type);
-	    }
-	  inject_this_parameter (class_type, TYPE_UNQUALIFIED);
-	  cp_parser_late_parsing_nsdmi (parser, decl);
-	}
-      vec_safe_truncate (unparsed_nsdmis, 0);
-      current_class_ptr = save_ccp;
-      current_class_ref = save_ccr;
-      if (pushed_scope)
-	pop_scope (pushed_scope);
 
       /* If there are noexcept-specifiers that have not yet been processed,
-	 take care of them now.  */
-      class_type = NULL_TREE;
-      pushed_scope = NULL_TREE;
+	 take care of them now.  Do this before processing NSDMIs as they
+	 may depend on noexcept-specifiers already having been processed.  */
       FOR_EACH_VEC_SAFE_ELT (unparsed_noexcepts, ix, decl)
 	{
 	  tree ctx = DECL_CONTEXT (decl);
@@ -25084,6 +25063,25 @@ cp_parser_class_specifier_1 (cp_parser* parser)
 	  maybe_end_member_template_processing ();
 	}
       vec_safe_truncate (unparsed_noexcepts, 0);
+
+      /* Now parse any NSDMIs.  */
+      save_ccp = current_class_ptr;
+      save_ccr = current_class_ref;
+      FOR_EACH_VEC_SAFE_ELT (unparsed_nsdmis, ix, decl)
+	{
+	  if (class_type != DECL_CONTEXT (decl))
+	    {
+	      if (pushed_scope)
+		pop_scope (pushed_scope);
+	      class_type = DECL_CONTEXT (decl);
+	      pushed_scope = push_scope (class_type);
+	    }
+	  inject_this_parameter (class_type, TYPE_UNQUALIFIED);
+	  cp_parser_late_parsing_nsdmi (parser, decl);
+	}
+      vec_safe_truncate (unparsed_nsdmis, 0);
+      current_class_ptr = save_ccp;
+      current_class_ref = save_ccr;
       if (pushed_scope)
 	pop_scope (pushed_scope);
 
diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept62.C b/gcc/testsuite/g++.dg/cpp0x/noexcept62.C
new file mode 100644
index 00000000000..53606c79142
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/noexcept62.C
@@ -0,0 +1,10 @@
+// PR c++/98333
+// { dg-do compile { target c++11 } }
+
+struct T {
+  template <bool N>
+  struct S {
+    S () noexcept (N) {}
+  };
+  int a = __has_nothrow_constructor (S<true>);
+};