From: David Malcolm <dmalcolm@redhat.com>
Date: Wed, 27 Jun 2018 23:21:46 +0000 (+0000)
Subject: C++: don't offer bogus "._0" suggestions (PR c++/86329)
X-Git-Tag: basepoints/gcc-10~5660
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5da1234bb7aaf95dd7e3b5e5438cd92be95daf0f;p=thirdparty%2Fgcc.git

C++: don't offer bogus "._0" suggestions (PR c++/86329)

PR c++/86329 reports that the C++ frontend can offer bogus suggestions like:

#include <string>

int compare()
{
  return __n1 - __n2;
}

suggested.cc: In function 'int compare()':
suggested.cc:5:10: error: '__n1' was not declared in this scope
   return __n1 - __n2;
          ^~~~
suggested.cc:5:10: note: suggested alternative: '._61'
   return __n1 - __n2;
          ^~~~
          ._61
suggested.cc:5:17: error: '__n2' was not declared in this scope
   return __n1 - __n2;
                 ^~~~
suggested.cc:5:17: note: suggested alternative: '._72'
   return __n1 - __n2;
                 ^~~~
                 ._72

The dot-prefixed names are an implementation detail of how we implement
anonymous enums found in the header files, generated via
anon_aggrname_format in make_anon_name.

This patch uses anon_aggrname_p to filter them out when considering
which names to suggest.

gcc/cp/ChangeLog:
	PR c++/86329
	* name-lookup.c (consider_binding_level): Filter out names that
	match anon_aggrname_p.

gcc/testsuite/ChangeLog:
	PR c++/86329
	* g++.dg/lookup/pr86329.C: New test.

From-SVN: r262199
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 05383b6003ab..040a84d02169 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2018-06-27  David Malcolm  <dmalcolm@redhat.com>
+
+	PR c++/86329
+	* name-lookup.c (consider_binding_level): Filter out names that
+	match anon_aggrname_p.
+
 2018-06-27  Jason Merrill  <jason@redhat.com>
 
 	* name-lookup.c (do_pushtag): If we skip a class level, also skip
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index e0500d830711..3aafb0f0ccf8 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -5786,6 +5786,11 @@ consider_binding_level (tree name, best_match <tree, const char *> &bm,
       if (!suggestion)
 	continue;
 
+      /* Don't suggest names that are for anonymous aggregate types, as
+	 they are an implementation detail generated by the compiler.  */
+      if (anon_aggrname_p (suggestion))
+	continue;
+
       const char *suggestion_str = IDENTIFIER_POINTER (suggestion);
 
       /* Ignore internal names with spaces in them.  */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e9e2e2a77680..3b33d2051f00 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-06-27  David Malcolm  <dmalcolm@redhat.com>
+
+	PR c++/86329
+	* g++.dg/lookup/pr86329.C: New test.
+
 2018-06-27  Carl Love  <cel@us.ibm.com>
 
 Add test case that was supposed to be added in commit 255556 on 2017-12-11.
diff --git a/gcc/testsuite/g++.dg/lookup/pr86329.C b/gcc/testsuite/g++.dg/lookup/pr86329.C
new file mode 100644
index 000000000000..fc091ba35de6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/lookup/pr86329.C
@@ -0,0 +1,11 @@
+/* PR c++/86329: ensure we don't erroneously offer suggestions like "._0",
+   which are an implementation detail of how e.g. anonymous enums are
+   handled internally.  */
+   
+enum {NONEMPTY};
+
+int test()
+{
+  return __0; // { dg-error "'__0' was not declared in this scope" }
+  // { dg-bogus "suggested alternative" "" { target *-*-* } .-1 }
+}