tests: check token redeclaration

[Akim Demaille]

commit 378963b1396272a1707e2f888dea7e2376a0e8ae
Author: Akim Demaille <address@hidden>
Date:   Fri Sep 6 17:47:16 2019 +0200

    tests: check token redeclaration
    
    * src/symtab.c (symbol_class_set): Report previous definitions when
    redeclared.
    * tests/input.at (Symbol redeclared): New.

diff --git a/src/symtab.c b/src/symtab.c
index 60733e72..684fdf3d 100644
--- a/src/symtab.c
+++ b/src/symtab.c
@@ -462,7 +462,13 @@ symbol_class_set (symbol *sym, symbol_class class, 
location loc, bool declaring)
       if (declaring)
         {
           if (s->status == declared)
-            complain (&loc, Wother, _("symbol %s redeclared"), sym->tag);
+            {
+              unsigned i = 0;
+              complain (&loc, Wother, _("symbol %s redeclared"), sym->tag);
+              i += SUB_INDENT;
+              complain_indent (&sym->location, Wother, &i,
+                               _("previous declaration"));
+            }
           else
             s->status = declared;
         }
diff --git a/tests/diagnostics.at b/tests/diagnostics.at
index 3f9e19fa..15815db3 100644
--- a/tests/diagnostics.at
+++ b/tests/diagnostics.at
@@ -67,18 +67,33 @@ exp: %empty;
 [[input.y:9.12-14: <warning>warning:</warning> symbol FOO redeclared 
[<warning>-Wother</warning>]
     9 | %token FOO <warning>FOO</warning> FOO
       |            <warning>^~~</warning>
+input.y:9.8-10: previous declaration
+    9 | %token <note>FOO</note> FOO FOO
+      |        <note>^~~</note>
 input.y:9.16-18: <warning>warning:</warning> symbol FOO redeclared 
[<warning>-Wother</warning>]
     9 | %token FOO FOO <warning>FOO</warning>
       |                <warning>^~~</warning>
+input.y:9.8-10: previous declaration
+    9 | %token <note>FOO</note> FOO FOO
+      |        <note>^~~</note>
 input.y:10.8-10: <warning>warning:</warning> symbol FOO redeclared 
[<warning>-Wother</warning>]
    10 | %token <warning>FOO</warning>  FOO  FOO
       |        <warning>^~~</warning>
+input.y:9.8-10: previous declaration
+    9 | %token <note>FOO</note> FOO FOO
+      |        <note>^~~</note>
 input.y:10.13-15: <warning>warning:</warning> symbol FOO redeclared 
[<warning>-Wother</warning>]
    10 | %token FOO  <warning>FOO</warning>  FOO
       |             <warning>^~~</warning>
+input.y:9.8-10: previous declaration
+    9 | %token <note>FOO</note> FOO FOO
+      |        <note>^~~</note>
 input.y:10.18-20: <warning>warning:</warning> symbol FOO redeclared 
[<warning>-Wother</warning>]
    10 | %token FOO  FOO  <warning>FOO</warning>
       |                  <warning>^~~</warning>
+input.y:9.8-10: previous declaration
+    9 | %token <note>FOO</note> FOO FOO
+      |        <note>^~~</note>
 ]])
 
 
diff --git a/tests/input.at b/tests/input.at
index 2cc829f5..660cacc9 100644
--- a/tests/input.at
+++ b/tests/input.at
@@ -615,6 +615,38 @@ AT_CHECK_UNUSED_VALUES([1], [1])
 AT_CLEANUP
 
 
+## ------------------- ##
+## Symbol redeclared.  ##
+## ------------------- ##
+
+AT_SETUP([Symbol redeclared])
+
+AT_DATA([[input.y]],
+[[%token FOO FOO
+%token BAR 12 BAR 12
+
+%%
+exp: FOO BAR
+]])
+
+AT_BISON_CHECK([-fcaret input.y], [0], [],
+[[input.y:1.12-14: warning: symbol FOO redeclared [-Wother]
+    1 | %token FOO FOO
+      |            ^~~
+input.y:1.8-10: previous declaration
+    1 | %token FOO FOO
+      |        ^~~
+input.y:2.15-17: warning: symbol BAR redeclared [-Wother]
+    2 | %token BAR 12 BAR 12
+      |               ^~~
+input.y:2.8-10: previous declaration
+    2 | %token BAR 12 BAR 12
+      |        ^~~
+]])
+
+AT_CLEANUP
+
+
 ## --------------------------- ##
 ## Symbol class redefinition.  ##
 ## --------------------------- ##
diff --git a/tests/regression.at b/tests/regression.at
index 507bcbb4..55a3c95b 100644
--- a/tests/regression.at
+++ b/tests/regression.at
@@ -397,19 +397,18 @@ AT_BISON_OPTION_POPDEFS
 # unnecessarily escaped here even though it would need to be if encoded in a
 # C-string literal.  Also notice that unnecessary escaping, such as "\?", from
 # the user specification is eliminated.
-AT_BISON_CHECK([-o input.c input.y], [[0]], [[]],
-[[input.y:22.8-14: warning: symbol SPECIAL redeclared [-Wother]
-input.y:22.16-63: warning: symbol "\\'?\"\a\b\f\n\r\t\v\001\201\001\201??!" 
used more than once as a literal string [-Wother]
-]])
-
 AT_BISON_CHECK([-fcaret -o input.c input.y], [[0]], [[]],
 [[input.y:22.8-14: warning: symbol SPECIAL redeclared [-Wother]
    22 | %token SPECIAL "\\\'\?\"\a\b\f\n\r\t\v\001\201\x001\x000081??!"
       |        ^~~~~~~
+input.y:21.8-14: previous declaration
+   21 | %token SPECIAL "\\\'\?\"\a\b\f\n\r\t\v\001\201\x001\x000081??!"
+      |        ^~~~~~~
 input.y:22.16-63: warning: symbol "\\'?\"\a\b\f\n\r\t\v\001\201\001\201??!" 
used more than once as a literal string [-Wother]
    22 | %token SPECIAL "\\\'\?\"\a\b\f\n\r\t\v\001\201\x001\x000081??!"
       |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 ]])
+
 AT_COMPILE([input])
 
 # Checking the error message here guarantees that yytname, which does contain