updates: insert/remove %empty

[Akim Demaille]

commit 971e72514fd38938ae5370ff13473e5111e886ce
Author: Akim Demaille <address@hidden>
Date:   Tue Apr 23 22:13:28 2019 +0200

    updates: insert/remove %empty
    
    * src/reader.c (grammar_rule_check_and_complete): Generate fixits for
    adding/removing %empty.
    * tests/actions.at, tests/diagnostics.at, tests/existing.at: Adjust.

diff --git a/src/reader.c b/src/reader.c
index e776ed1f..32feb0dc 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -26,6 +26,7 @@
 #include "complain.h"
 #include "conflicts.h"
 #include "files.h"
+#include "fixits.h"
 #include "getargs.h"
 #include "gram.h"
 #include "muscle-tab.h"
@@ -344,14 +345,22 @@ grammar_rule_check_and_complete (symbol_list *r)
   /* Check that %empty => empty rule.  */
   if (r->percent_empty_loc.start.file
       && r->next && r->next->content.sym)
-    complain (&r->percent_empty_loc, complaint,
-              _("%%empty on non-empty rule"));
+    {
+      complain (&r->percent_empty_loc, complaint,
+                _("%%empty on non-empty rule"));
+      fixits_register (&r->percent_empty_loc, "");
+    }
 
   /* Check that empty rule => %empty.  */
   if (!(r->next && r->next->content.sym)
       && !r->midrule_parent_rule
-      && !r->percent_empty_loc.start.file)
-    complain (&r->location, Wempty_rule, _("empty rule without %%empty"));
+      && !r->percent_empty_loc.start.file
+      && warning_is_enabled (Wempty_rule))
+    {
+      complain (&r->location, Wempty_rule,
+                _("empty rule without %%empty"));
+      fixits_register (&r->location, " %empty ");
+    }
 
   /* See comments in grammar_current_rule_prec_set for how POSIX
      mandates this complaint.  It's only for identifiers, so skip
diff --git a/tests/actions.at b/tests/actions.at
index ec2e8836..7157805b 100644
--- a/tests/actions.at
+++ b/tests/actions.at
@@ -134,6 +134,7 @@ AT_BISON_CHECK([-fcaret -Wempty-rule 1.y], [0], [],
 [[1.y:11.17-18: warning: empty rule without %empty [-Wempty-rule]
    11 | a: /* empty. */ {};
       |                 ^~
+1.y: warning: fix-its can be applied.  Rerun with option '--update'. [-Wother]
 ]])
 
 AT_DATA_GRAMMAR([[2.y]],
@@ -151,6 +152,7 @@ AT_BISON_CHECK([-fcaret 2.y], [0], [],
 2.y:13.17-18: warning: empty rule without %empty [-Wempty-rule]
    13 | c: /* empty. */ {};
       |                 ^~
+2.y: warning: fix-its can be applied.  Rerun with option '--update'. [-Wother]
 ]])
 
 AT_BISON_CHECK([-fcaret -Wno-empty-rule 2.y], [0])
@@ -229,6 +231,7 @@ two.y:12.3-8: error: %empty on non-empty rule
 two.y:13.3-8: error: %empty on non-empty rule
    13 | | %empty {}     {}
       |   ^~~~~~
+two.y: warning: fix-its can be applied.  Rerun with option '--update'. 
[-Wother]
 ]])
 
 AT_BISON_OPTION_POPDEFS
diff --git a/tests/diagnostics.at b/tests/diagnostics.at
index ab5fde38..773982ff 100644
--- a/tests/diagnostics.at
+++ b/tests/diagnostics.at
@@ -112,6 +112,7 @@ input.y:16.2: <warning>warning:</warning> empty rule 
without %empty [<warning>-W
 input.y:17.3: <warning>warning:</warning> empty rule without %empty 
[<warning>-Wempty-rule</warning>]
    17 | e:
       |   <warning>^</warning>
+input.y: <warning>warning:</warning> fix-its can be applied.  Rerun with 
option '--update'. [<warning>-Wother</warning>]
 ]])
 
 
@@ -158,6 +159,7 @@ input.y:17.4-17: <warning>warning:</warning> empty rule 
without %empty [<warning
 input.y:18.4-17: <warning>warning:</warning> empty rule without %empty 
[<warning>-Wempty-rule</warning>]
    18 | h: <warning>{  🐃       }</warning>
       |    <warning>^~~~~~~~~~~~~~</warning>
+input.y: <warning>warning:</warning> fix-its can be applied.  Rerun with 
option '--update'. [<warning>-Wother</warning>]
 ]])
 
 
@@ -180,6 +182,7 @@ b: {}
    11 | a: <warning>{}</warning>
       |    <warning>^~</warning>
 /dev/stdout:1.4-5: <warning>warning:</warning> empty rule without %empty 
[<warning>-Wempty-rule</warning>]
+/dev/stdout: <warning>warning:</warning> fix-its can be applied.  Rerun with 
option '--update'. [<warning>-Wother</warning>]
 ]])
 
 
diff --git a/tests/existing.at b/tests/existing.at
index 782633ad..018178bf 100644
--- a/tests/existing.at
+++ b/tests/existing.at
@@ -457,6 +457,7 @@ input.y:47.1-6: warning: useless associativity for UNARY, 
use %precedence [-Wpre
 input.y:50.1-5: warning: useless associativity for '$', use %precedence 
[-Wprecedence]
 input.y:51.1-5: warning: useless associativity for '(', use %precedence 
[-Wprecedence]
 input.y:51.1-5: warning: useless precedence and associativity for ')' 
[-Wprecedence]
+input.y: warning: fix-its can be applied.  Rerun with option '--update'. 
[-Wother]
 ]],
 
 dnl LAST-STATE
@@ -1428,6 +1429,7 @@ input.y:54.1-5: warning: useless associativity for 
HORELSE, use %precedence [-Wp
 input.y:55.1-5: warning: useless associativity for HANDTHEN, use %precedence 
[-Wprecedence]
 input.y:61.1-5: warning: useless associativity for HNOT, use %precedence 
[-Wprecedence]
 input.y:68.1-5: warning: useless associativity for UNEAR, use %precedence 
[-Wprecedence]
+input.y: warning: fix-its can be applied.  Rerun with option '--update'. 
[-Wother]
 ]],
 
 dnl LAST-STATE
@@ -2096,6 +2098,7 @@ input.y:157.1-5: warning: useless associativity for '`', 
use %precedence [-Wprec
 input.y:159.1-5: warning: useless associativity for '@<:@', use %precedence 
[-Wprecedence]
 input.y:170.1-5: warning: useless associativity for ',', use %precedence 
[-Wprecedence]
 input.y:181.1-6: warning: useless associativity for '!', use %precedence 
[-Wprecedence]
+input.y: warning: fix-its can be applied.  Rerun with option '--update'. 
[-Wother]
 ]],
 
 dnl LAST-STATE