[gcc r10-10692] c++: Don't suggest cdtor or conversion op identifiers in spelling hints [PR104806]

[Jakub Jelinek <jakub@gcc.gnu.org>]

https://gcc.gnu.org/g:da83eb387b2e0e4dfab73b735beac87ed269c866

commit r10-10692-gda83eb387b2e0e4dfab73b735beac87ed269c866
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Mar 8 21:41:21 2022 +0100

    c++: Don't suggest cdtor or conversion op identifiers in spelling hints [PR104806]
    
    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.
    
    2022-03-08  Jakub Jelinek  <jakub@redhat.com>
    
            PR c++/104806
            * search.c (lookup_field_fuzzy_info::fuzzy_lookup_field): Ignore
            identifiers with space at the end.
    
            * g++.dg/spellcheck-pr104806.C: New test.
    
    (cherry picked from commit e480c3c06d20874fd7504bfdcca0b829f8000389)

Diff:
---
 gcc/cp/search.c                            | 7 +++++++
 gcc/testsuite/g++.dg/spellcheck-pr104806.C | 5 +++++
 2 files changed, 12 insertions(+)

diff --git a/gcc/cp/search.c b/gcc/cp/search.c
index 6eada2d3788..dd013f9d668 100644
--- a/gcc/cp/search.c
+++ b/gcc/cp/search.c
@@ -1249,6 +1249,13 @@ lookup_field_fuzzy_info::fuzzy_lookup_field (tree type)
       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));
     }
 }
diff --git a/gcc/testsuite/g++.dg/spellcheck-pr104806.C b/gcc/testsuite/g++.dg/spellcheck-pr104806.C
new file mode 100644
index 00000000000..559e6019163
--- /dev/null
+++ b/gcc/testsuite/g++.dg/spellcheck-pr104806.C
@@ -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 }