[PATCH] c++: Don't suggest cdtor or conversion op identifiers in spelling hints [PR104806]

[Jakub Jelinek <jakub@redhat.com>]

Hi!

On the following testcase, we emit "did you mean '__dt '?" in the error
message.  "__dt " shows there because it is dtor_identifier, but we
shouldn't suggest those to the user, they are purely internal and can't
be really typed by the user because of the final space in it.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2022-03-08  Jakub Jelinek  <jakub@redhat.com>

	PR c++/104806
	* search.cc (lookup_field_fuzzy_info::fuzzy_lookup_field): Ignore
	identifiers with space at the end.

	* g++.dg/spellcheck-pr104806.C: New test.

--- gcc/cp/search.cc.jj	2022-01-18 11:58:59.407984557 +0100
+++ gcc/cp/search.cc	2022-03-07 10:44:33.455673155 +0100
@@ -1275,6 +1275,13 @@ lookup_field_fuzzy_info::fuzzy_lookup_fi
       if (is_lambda_ignored_entity (field))
 	continue;
 
+      /* Ignore special identifiers with space at the end like cdtor or
+	 conversion op identifiers.  */
+      if (TREE_CODE (DECL_NAME (field)) == IDENTIFIER_NODE)
+	if (unsigned int len = IDENTIFIER_LENGTH (DECL_NAME (field)))
+	  if (IDENTIFIER_POINTER (DECL_NAME (field))[len - 1] == ' ')
+	    continue;
+
       m_candidates.safe_push (DECL_NAME (field));
     }
 }
--- gcc/testsuite/g++.dg/spellcheck-pr104806.C.jj	2022-03-07 10:34:07.224499657 +0100
+++ gcc/testsuite/g++.dg/spellcheck-pr104806.C	2022-03-07 10:43:41.900399808 +0100
@@ -0,0 +1,5 @@
+// PR c++/104806
+
+struct S {};
+int main() { S s; s.__d; }	// { dg-bogus "'struct S' has no member named '__d'; did you mean '__\[a-z]* '" }
+				// { dg-error "'struct S' has no member named '__d'" "" { target *-*-* } .-1 }

	Jakub