[pushed] c: add name hints to c_parser_declspecs [PR107583]

[pushed] c: add name hints to c_parser_declspecs [PR107583]

[David Malcolm]

PR c/107583 notes that we weren't issuing a hint for

  struct foo {
    time_t mytime; /* missing <time.h> include should trigger fixit */
  };

in the C frontend.

The root cause is that one of the "unknown type name" diagnostics
was missing logic to emit hints, which this patch fixes.

Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu.
Pushed to trunk as r14-1876-g57446d1bc9757e.

gcc/c/ChangeLog:
	PR c/107583
	* c-parser.cc (c_parser_declspecs): Add hints to "unknown type
	name" error.

gcc/testsuite/ChangeLog:
	PR c/107583
	* c-c++-common/spellcheck-pr107583.c: New test.
---
 gcc/c/c-parser.cc                                | 14 +++++++++++++-
 gcc/testsuite/c-c++-common/spellcheck-pr107583.c | 10 ++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/c-c++-common/spellcheck-pr107583.c

diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 5baa501dbee..f8b14e4c688 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -3182,7 +3182,19 @@ c_parser_declspecs (c_parser *parser, struct c_declspecs *specs,
 	  attrs_ok = true;
 	  if (kind == C_ID_ID)
 	    {
-	      error_at (loc, "unknown type name %qE", value);
+	      auto_diagnostic_group d;
+	      name_hint hint = lookup_name_fuzzy (value, FUZZY_LOOKUP_TYPENAME,
+						  loc);
+	      if (const char *suggestion = hint.suggestion ())
+		{
+		  gcc_rich_location richloc (loc);
+		  richloc.add_fixit_replace (suggestion);
+		  error_at (&richloc,
+			    "unknown type name %qE; did you mean %qs?",
+			    value, suggestion);
+		}
+	      else
+		error_at (loc, "unknown type name %qE", value);
 	      t.kind = ctsk_typedef;
 	      t.spec = error_mark_node;
 	    }
diff --git a/gcc/testsuite/c-c++-common/spellcheck-pr107583.c b/gcc/testsuite/c-c++-common/spellcheck-pr107583.c
new file mode 100644
index 00000000000..86a9e7dbcb6
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/spellcheck-pr107583.c
@@ -0,0 +1,10 @@
+struct s1 {
+  time_t mytime; /* { dg-error "unknown type name 'time_t'" "c error" { target c } } */
+  /* { dg-error "'time_t' does not name a type" "c++ error" { target c++ } .-1 } */
+  /* { dg-message "'time_t' is defined in header" "hint" { target *-*-* } .-2 } */
+};
+
+struct s2 {
+  unsinged i; /* { dg-error "unknown type name 'unsinged'; did you mean 'unsigned'." "c error" { target c } } */
+  /* { dg-error "'unsinged' does not name a type; did you mean 'unsigned'." "c++ error" { target c++ } .-1 } */
+};
-- 
2.26.3