Re: [PATCH] Fix location of typeid() (PR c++/80014)

[Jason Merrill]

On Tue, Mar 14, 2017 at 9:05 PM, David Malcolm  wrote:
> OK for trunk now, or should this wait until stage 1?

Stage 1.

> +   cp_token *close_paren = cp_parser_require (parser, CPP_CLOSE_PAREN,
> +  RT_CLOSE_PAREN);
> +   location_t end_loc = close_paren ?
> + close_paren->location : UNKNOWN_LOCATION;
> /* If all went well, simply lookup the type-id.  */
> if (cp_parser_parse_definitely (parser))
>   postfix_expression = get_typeid (type, tf_warning_or_error);
> @@ -6527,13 +6530,23 @@ cp_parser_postfix_expression (cp_parser *parser, bool 
> address_p, bool cast_p,
> /* Compute its typeid.  */
> postfix_expression = build_typeid (expression, 
> tf_warning_or_error);
> /* Look for the `)' token.  */
> -   cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
> +   close_paren
> + = cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
> +   end_loc = close_paren ? close_paren->location : UNKNOWN_LOCATION;

In both cases you're setting end_loc from close_paren, so how about
only computing it once, closer to where it's used?

Jason

[PATCH] Fix location of typeid() (PR c++/80014)

[David Malcolm]

PR c++/80014 reports an issue where no caret is printed when issuing an
error for this bogus code:
  !typeid(void);

Root cause is that we're not setting up the location for the cp_expr for
the typeid expression, so that
  !typeid(void)
has start == caret at the '!', but finish == UNKNOWN_LOCATION, and so
the layout ctor within diagnostic-show-locus.c filters out the primary
range, and hence layout::should_print_annotation_line_p returns false.

This patch fixes things by setting up a location for the typeid
expression when parsing it.

Successfully bootstrapped on x86_64-pc-linux-gnu.

OK for trunk now, or should this wait until stage 1?

gcc/cp/ChangeLog:
PR c++/80014
* parser.c (cp_parser_postfix_expression): Construct a location
for typeid expressions.

gcc/testsuite/ChangeLog:
PR c++/80014
* g++.dg/plugin/diagnostic-test-expressions-1.C (std::type_info):
Add declaration.
(test_typeid): New test function.
---
 gcc/cp/parser.c| 17 --
 .../g++.dg/plugin/diagnostic-test-expressions-1.C  | 26 ++
 2 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index c1b6496..aecf9a5 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -6513,7 +6513,10 @@ cp_parser_postfix_expression (cp_parser *parser, bool 
address_p, bool cast_p,
/* Look for the `)' token.  Otherwise, we can't be sure that
   we're not looking at an expression: consider `typeid (int
   (3))', for example.  */
-   cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+   cp_token *close_paren = cp_parser_require (parser, CPP_CLOSE_PAREN,
+  RT_CLOSE_PAREN);
+   location_t end_loc = close_paren ?
+ close_paren->location : UNKNOWN_LOCATION;
/* If all went well, simply lookup the type-id.  */
if (cp_parser_parse_definitely (parser))
  postfix_expression = get_typeid (type, tf_warning_or_error);
@@ -6527,13 +6530,23 @@ cp_parser_postfix_expression (cp_parser *parser, bool 
address_p, bool cast_p,
/* Compute its typeid.  */
postfix_expression = build_typeid (expression, tf_warning_or_error);
/* Look for the `)' token.  */
-   cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+   close_paren
+ = cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+   end_loc = close_paren ? close_paren->location : UNKNOWN_LOCATION;
  }
/* Restore the saved message.  */
parser->type_definition_forbidden_message = saved_message;
/* `typeid' may not appear in an integral constant expression.  */
if (cp_parser_non_integral_constant_expression (parser, NIC_TYPEID))
  postfix_expression = error_mark_node;
+
+   /* Construct a location e.g. :
+typeid (expr)
+^
+  ranging from the start of the "typeid" token to the final closing
+  paren, with the caret at the start.  */
+   location_t typeid_loc = make_location (start_loc, start_loc, end_loc);
+   postfix_expression.set_location (typeid_loc);
   }
   break;
 
diff --git a/gcc/testsuite/g++.dg/plugin/diagnostic-test-expressions-1.C 
b/gcc/testsuite/g++.dg/plugin/diagnostic-test-expressions-1.C
index 4d3b07c..3554086 100644
--- a/gcc/testsuite/g++.dg/plugin/diagnostic-test-expressions-1.C
+++ b/gcc/testsuite/g++.dg/plugin/diagnostic-test-expressions-1.C
@@ -782,3 +782,29 @@ tests::test_method_calls ()
~~^~
{ dg-end-multiline-output "" } */
 }
+
+namespace std
+{
+  class type_info { public: int foo; };
+}
+
+void test_typeid (int i)
+{
+  __emit_expression_range (0, (i)); /* { dg-warning "range" } */
+/* { dg-begin-multiline-output "" }
+   __emit_expression_range (0, (i));
+   ^~
+   { dg-end-multiline-output "" } */
+
+  __emit_expression_range (0, (i * 2)); /* { dg-warning "range" } */
+/* { dg-begin-multiline-output "" }
+   __emit_expression_range (0, (i * 2));
+   ^~
+   { dg-end-multiline-output "" } */
+
+  __emit_expression_range (0, typeid(int).foo); /* { dg-warning "range" } */
+/* { dg-begin-multiline-output "" }
+   __emit_expression_range (0, typeid(int).foo);
+   ^~~
+   { dg-end-multiline-output "" } */
+}
-- 
1.8.5.3