Re: [PATCH 8/8] diagnostics: suggest fixes for undeclared symbols

[Akim Demaille]

> Le 2 oct. 2019 à 08:22, Akim Demaille <address@hidden> a écrit :
> 
> From
> 
>    input.y:1.17-19: warning: symbol baz is used, but is not defined as a 
> token and has no rules [-Wother]
>         1 | %printer {} foo baz
>           |                 ^~~
> 
> to
> 
>    input.y:1.17-19: warning: symbol 'baz' is used, but is not defined as a 
> token and has no rules; did you mean 'bar'? [-Wother]
>        1 | %printer {} foo baz
>          |                 ^~~
>          |                 bar
> 
> * bootstrap.conf: We need fstrcmp.
> * src/symtab.c (symbol_from_uniqstr_fuzzy): New.
> (complain_symbol_undeclared): Use it.
> * tests/input.at: Adjust expectations.

I appended this patch to that series:

commit fec13ce2db675d18afb887e3c98f347a2b3de31e
Author: Akim Demaille <address@hidden>
Date:   Wed Oct 2 08:57:58 2019 +0200

    diagnostics: sort symbols per location
    
    Because the checking of the grammar is made by phases after the whole
    grammar was read, we sometimes have diagnostics that look weird.  In
    some case, within one type of checking, the entities are not checked
    in the order in which they appear in the file.  For instance, checking
    symbols is done on the list of symbols sorted by tag:
    
        foo.y:1.20-22: warning: symbol BAR is used, but is not defined as a 
token and has no rules [-Wother]
            1 | %destructor {} QUX BAR
              |                    ^~~
        foo.y:1.16-18: warning: symbol QUX is used, but is not defined as a 
token and has no rules [-Wother]
            1 | %destructor {} QUX BAR
              |                ^~~
    
    Let's sort them by location instead:
    
        foo.y:1.16-18: warning: symbol 'QUX' is used, but is not defined as a 
token and has no rules [-Wother]
            1 | %destructor {} QUX BAR
              |                ^~~
        foo.y:1.20-22: warning: symbol 'BAR' is used, but is not defined as a 
token and has no rules [-Wother]
            1 | %destructor {} QUX BAR
              |                    ^~~
    
    * src/location.h (location_cmp): Be robust to empty file names.
    * src/symtab.c (symbol_cmp): Sort by location.
    * tests/input.at: Adjust expectations.

diff --git a/src/location.h b/src/location.h
index 8eb7c472..cbd6f482 100644
--- a/src/location.h
+++ b/src/location.h
@@ -71,7 +71,12 @@ boundary_set (boundary *p, const char *f, int l, int c, int 
b)
 static inline int
 boundary_cmp (boundary a, boundary b)
 {
-  int res = strcmp (a.file, b.file);
+  /* Locations with no file first.  */
+  int res =
+    a.file && b.file ? strcmp (a.file, b.file)
+    : a.file ? 1
+    : b.file ? -1
+    : 0;
   if (!res)
     res = a.line - b.line;
   if (!res)
diff --git a/src/symtab.c b/src/symtab.c
index b3642e67..f2454725 100644
--- a/src/symtab.c
+++ b/src/symtab.c
@@ -925,8 +925,8 @@ symbols_free (void)
 static int
 symbol_cmp (void const *a, void const *b)
 {
-  return strcmp ((*(symbol * const *)a)->tag,
-                 (*(symbol * const *)b)->tag);
+  return location_cmp ((*(symbol * const *)a)->location,
+                       (*(symbol * const *)b)->location);
 }
 
 /* Store in *SORTED an array of pointers to the symbols contained in
@@ -952,14 +952,13 @@ void
 symbols_check_defined (void)
 {
   table_sort (symbol_table, &symbols_sorted);
-  /* semantic_type, like symbol, starts with a 'tag' field.  And here
-     we only deal with arrays/hashes of pointers, sizeof is not an
-     issue.
+  /* semantic_type, like symbol, starts with a 'tag' field and then a
+     'location' field.  And here we only deal with arrays/hashes of
+     pointers, sizeof is not an issue.
 
      So instead of implementing table_sort (and symbol_cmp) once for
      each type, let's lie a bit to the typing system, and treat
-     'semantic_type' as if it were 'symbol'.  Anyway this is only
-     about arrays of pointers.  */
+     'semantic_type' as if it were 'symbol'. */
   table_sort (semantic_type_table, (symbol ***) &semantic_types_sorted);
 
   for (int i = 0; symbols_sorted[i]; ++i)
@@ -1019,7 +1018,7 @@ symbols_token_translations_init (void)
   for (int i = 0; i < max_user_token_number + 1; ++i)
     token_translations[i] = undeftoken->content->number;
   for (int i = 0; symbols_sorted[i]; ++i)
-    symbol_translation(symbols_sorted[i]);
+    symbol_translation (symbols_sorted[i]);
 }
 
 
@@ -1033,7 +1032,7 @@ symbols_pack (void)
 {
   symbols = xcalloc (nsyms, sizeof *symbols);
   for (int i = 0; symbols_sorted[i]; ++i)
-    symbol_pack(symbols_sorted[i]);
+    symbol_pack (symbols_sorted[i]);
 
   /* Aliases leave empty slots in symbols, so remove them.  */
   {
diff --git a/tests/diagnostics.at b/tests/diagnostics.at
index bd01c15d..deac06ff 100644
--- a/tests/diagnostics.at
+++ b/tests/diagnostics.at
@@ -427,16 +427,16 @@ res: QUX baz
 bar: QUUX
 ]],
 [1],
-[[input.y:11.6-9: <error>error:</error> symbol 'QUUX' is used, but is not 
defined as a token and has no rules
-   11 | bar: <error>QUUX</error>
-      |      <error>^~~~</error>
-input.y:10.6-8: <error>error:</error> symbol 'QUX' is used, but is not defined 
as a token and has no rules
+[[input.y:10.6-8: <error>error:</error> symbol 'QUX' is used, but is not 
defined as a token and has no rules
    10 | res: <error>QUX</error> baz
       |      <error>^~~</error>
 input.y:10.10-12: <error>error:</error> symbol 'baz' is used, but is not 
defined as a token and has no rules; did you mean 'bar'?
    10 | res: QUX <error>baz</error>
       |          <error>^~~</error>
       |          <fixit-insert>bar</fixit-insert>
+input.y:11.6-9: <error>error:</error> symbol 'QUUX' is used, but is not 
defined as a token and has no rules
+   11 | bar: <error>QUUX</error>
+      |      <error>^~~~</error>
 ]])
 
 
diff --git a/tests/input.at b/tests/input.at
index e5d7666b..976e5395 100644
--- a/tests/input.at
+++ b/tests/input.at
@@ -822,15 +822,15 @@ exp: bar;
 ]])
 
 AT_BISON_CHECK([-fcaret input.y], [1], [],
-[[input.y:2.16-18: error: symbol 'bar' is used, but is not defined as a token 
and has no rules
-    2 | %destructor {} bar
-      |                ^~~
+[[input.y:1.13-15: warning: symbol 'foo' is used, but is not defined as a 
token and has no rules [-Wother]
+    1 | %printer {} foo baz
+      |             ^~~
 input.y:1.17-19: warning: symbol 'baz' is used, but is not defined as a token 
and has no rules [-Wother]
     1 | %printer {} foo baz
       |                 ^~~
-input.y:1.13-15: warning: symbol 'foo' is used, but is not defined as a token 
and has no rules [-Wother]
-    1 | %printer {} foo baz
-      |             ^~~
+input.y:2.16-18: error: symbol 'bar' is used, but is not defined as a token 
and has no rules
+    2 | %destructor {} bar
+      |                ^~~
 input.y:3.13-15: warning: symbol 'qux' is used, but is not defined as a token 
and has no rules [-Wother]
     3 | %type <foo> qux
       |             ^~~
@@ -1061,9 +1061,9 @@ AT_BISON_CHECK([-fcaret input.y], [1], [],
 input.y:2.10-12: error: user token number 42 redeclaration for BAR
     2 |          BAR 42 "foo"
       |          ^~~
-input.y:1.8-10:      previous declaration for FOO
+input.y:1.15-19:     previous declaration for "foo"
     1 | %token FOO 42 "foo"
-      |        ^~~
+      |               ^~~~~
 ]])
 
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