Reimplement removal fix-it hints in terms of replace

This patch eliminates class fixit_remove, reimplementing
rich_location::add_fixit_remove in terms of replacement with the
empty string.  Deleting the removal subclass simplifies
fixit-handling code, as we only have two concrete fixit_hint
subclasses to deal with, rather than three.

The patch also fixes some problems in diagnostic-show-locus.c for
situations where a replacement fix-it has a different range to the
range of the diagnostic, by unifying the drawing of the two kinds of
fixits.  For example, this:

  foo = bar.field;
      ^
            m_field

becomes:

  foo = bar.field;
      ^
            -----
            m_field

showing the range to be replaced.

gcc/ChangeLog:
	* diagnostic-show-locus.c
	(layout::annotation_line_showed_range_p): New method.
	(layout::print_any_fixits): Remove case fixit_hint::REMOVE.
	Reimplement case fixit_hint::REPLACE to cover removals, and
	replacements where the range of the replacement isn't one
	of the ranges in the rich_location.
	(test_one_liner_fixit_replace): Likewise.
	(selftest::test_one_liner_fixit_replace_non_equal_range): New
	function.
	(selftest::test_one_liner_fixit_replace_equal_secondary_range):
	New function.
	(selftest::test_diagnostic_show_locus_one_liner): Call the new
	functions.
	* diagnostic.c (print_parseable_fixits): Remove case
	fixit_hint::REMOVE.

libcpp/ChangeLog:
	* include/line-map.h (fixit_hint::kind): Delete REPLACE.
	(class fixit_remove): Delete.
	* line-map.c (rich_location::add_fixit_remove): Reimplement
	by calling add_fixit_replace with an empty string.
	(fixit_remove::fixit_remove): Delete.
	(fixit_remove::affects_line_p): Delete.

From-SVN: r239632

libcpp/ChangeLog

@@ -1,3 +1,12 @@
+2016-08-19  David Malcolm  <dmalcolm@redhat.com>
+
+	* include/line-map.h (fixit_hint::kind): Delete REPLACE.
+	(class fixit_remove): Delete.
+	* line-map.c (rich_location::add_fixit_remove): Reimplement
+	by calling add_fixit_replace with an empty string.
+	(fixit_remove::fixit_remove): Delete.
+	(fixit_remove::affects_line_p): Delete.
+
 2016-08-19  Joseph Myers  <joseph@codesourcery.com>
 
 	PR c/32187

libcpp/include/line-map.h

@@ -1422,7 +1422,7 @@ protected:
 class fixit_hint
 {
 public:
-  enum kind {INSERT, REMOVE, REPLACE};
+  enum kind {INSERT, REPLACE};
 
   virtual ~fixit_hint () {}
 
@@ -1453,27 +1453,6 @@ class fixit_insert : public fixit_hint
   size_t m_len;
 };
 
-class fixit_remove : public fixit_hint
-{
- public:
-  fixit_remove (source_range src_range);
-  ~fixit_remove () {}
-
-  enum kind get_kind () const { return REMOVE; }
-  bool affects_line_p (const char *file, int line);
-  source_location get_start_loc () const { return m_src_range.m_start; }
-  bool maybe_get_end_loc (source_location *out) const
-  {
-    *out = m_src_range.m_finish;
-    return true;
-  }
-
-  source_range get_range () const { return m_src_range; }
-
- private:
-  source_range m_src_range;
-};
-
 class fixit_replace : public fixit_hint
 {
  public:

libcpp/line-map.c

@@ -2086,8 +2086,7 @@ rich_location::add_fixit_insert (source_location where,
 void
 rich_location::add_fixit_remove (source_range src_range)
 {
-  linemap_assert (m_num_fixit_hints < MAX_FIXIT_HINTS);
-  m_fixit_hints[m_num_fixit_hints++] = new fixit_remove (src_range);
+  add_fixit_replace (src_range, "");
 }
 
 /* Add a fixit-hint, suggesting replacement of the content at
@@ -2130,21 +2129,6 @@ fixit_insert::affects_line_p (const char *file, int line)
   return false;
 }
 
-/* class fixit_remove.  */
-
-fixit_remove::fixit_remove (source_range src_range)
-: m_src_range (src_range)
-{
-}
-
-/* Implementation of fixit_hint::affects_line_p for fixit_remove.  */
-
-bool
-fixit_remove::affects_line_p (const char *file, int line)
-{
-  return m_src_range.intersects_line_p (file, line);
-}
-
 /* class fixit_replace.  */
 
 fixit_replace::fixit_replace (source_range src_range,