cex: display all the S/R conflicts, not just one per (state, rule)

[Akim Demaille]

commit b65bd16e45d5ce1a9404cd46ea3b32256e2e477d
Author: Akim Demaille <akim.demaille@gmail.com>
Date:   Tue Jun 16 08:37:28 2020 +0200

    cex: display all the S/R conflicts, not just one per (state, rule)
    
    Before this commit, on
    
        %%
        exp
        : "if" exp "then" exp
        | "if" exp "then" exp "else" exp
        | exp "+" exp
        | "num"
    
    we used to not display the third counterexample below:
    
        Shift/reduce conflict on token "+":
          Example              exp "+" exp . "+" exp
          First derivation     exp ::=[ exp ::=[ exp "+" exp . ] "+" exp ]
          Second derivation    exp ::=[ exp "+" exp ::=[ exp . "+" exp ] ]
    
        Shift/reduce conflict on token "else":
          Example              "if" exp "then" "if" exp "then" exp . "else" exp
          First derivation     exp ::=[ "if" exp "then" exp ::=[ "if" exp 
"then" exp . ] "else" exp ]
          Second derivation    exp ::=[ "if" exp "then" exp ::=[ "if" exp 
"then" exp . "else" exp ] ]
    
        Shift/reduce conflict on token "+":
          Example              "if" exp "then" exp . "+" exp
          First derivation     exp ::=[ exp ::=[ "if" exp "then" exp . ] "+" 
exp ]
          Second derivation    exp ::=[ "if" exp "then" exp ::=[ exp . "+" exp 
] ]
    
        Shift/reduce conflict on token "+":
          Example              "if" exp "then" exp "else" exp . "+" exp
          First derivation     exp ::=[ exp ::=[ "if" exp "then" exp "else" exp 
. ] "+" exp ]
          Second derivation    exp ::=[ "if" exp "then" exp "else" exp ::=[ exp 
. "+" exp ] ]
    
    * src/counterexample.c (counterexample_report_state): Don't stop of
    the first conflicts.
    * tests/conflicts.at, tests/counterexample.at, tests/diagnostics.at,
    * tests/report.at: Adjust.

diff --git a/TODO b/TODO
index 2fa508aa..3f21d72d 100644
--- a/TODO
+++ b/TODO
@@ -37,10 +37,6 @@ Unless we play it dumb (little structure).
 
 Use "•" instead of ".".
 
-*** Conflict coverage
-Not all the conflicts have counterexamples generated.  See the "break"s in
-counterexample_report_state.
-
 *** point, dot
 We have too many names.  In XML we use "point", in C "dot".  A traditional
 more accurate name of "item" is "pointed rule", so we should probably prefer
diff --git a/src/counterexample.c b/src/counterexample.c
index e5b3a0af..a60456b5 100644
--- a/src/counterexample.c
+++ b/src/counterexample.c
@@ -1279,20 +1279,16 @@ counterexample_report_state (const state *s, FILE *out, 
const char *prefix)
   const reductions *reds = s->reductions;
   for (int i = 0; i < reds->num; ++i)
     {
-      rule *r1 = reds->rules[i];
+      const rule *r1 = reds->rules[i];
       const state_item_number c1 = find_state_item_number (r1, sn);
       for (int j = state_item_map[sn]; j < state_item_map[sn + 1]; ++j)
+        if (!SI_DISABLED (j))
           {
-          if (SI_DISABLED (j))
-            continue;
             state_item *si = state_items + j;
             item_number conf = *si->item;
             if (item_number_is_symbol_number (conf)
               && bitset_test (reds->lookahead_tokens[i], conf))
-            {
               counterexample_report_shift_reduce (c1, j, conf, out, prefix);
-              break;
-            }
           }
       for (int j = i+1; j < reds->num; ++j)
         {
@@ -1302,12 +1298,10 @@ counterexample_report_state (const state *s, FILE *out, 
const char *prefix)
                                reds->lookahead_tokens[j]);
           if (!bitset_empty_p (conf))
             {
-              rule *r2 = reds->rules[j];
-              for (int k = state_item_map[sn];
-                   k < state_item_map[sn + 1]; ++k)
+              const rule *r2 = reds->rules[j];
+              for (int k = state_item_map[sn]; k < state_item_map[sn + 1]; ++k)
+                if (!SI_DISABLED (k))
                   {
-                  if (SI_DISABLED (k))
-                    continue;
                     state_item *si = state_items + k;
                     const rule *r = item_rule (si->item);
                     if (r == r2)
diff --git a/tests/conflicts.at b/tests/conflicts.at
index 95ab79df..7a1cafee 100644
--- a/tests/conflicts.at
+++ b/tests/conflicts.at
@@ -1758,6 +1758,14 @@ State 4
       Second example           resolved_conflict . 'a' 'a'
       Second derivation        start ::=[ resolved_conflict reported_conflicts 
::=[ . 'a' ] 'a' ]
 
+    Shift/reduce conflict on token 'a':
+       10 reported_conflicts: . %empty
+        9 reported_conflicts: . 'a'
+      First example            resolved_conflict . 'a'
+      First derivation         start ::=[ resolved_conflict reported_conflicts 
::=[ . ] 'a' ]
+      Second example           resolved_conflict . 'a' 'a'
+      Second derivation        start ::=[ resolved_conflict reported_conflicts 
::=[ . 'a' ] 'a' ]
+
 
 
 State 5
diff --git a/tests/counterexample.at b/tests/counterexample.at
index 48d5acf3..92ce5109 100644
--- a/tests/counterexample.at
+++ b/tests/counterexample.at
@@ -79,6 +79,11 @@ Shift/reduce conflict on token B:
   First derivation     s ::=[ a ::=[ A . ] bc ::=[ B C ] ]
   Second derivation    s ::=[ ac ::=[ A ac ::=[ b ::=[ . B ] ] C ] ]
 
+Shift/reduce conflict on token B:
+  Example              A A . B B C C
+  First derivation     s ::=[ a ::=[ A a ::=[ A . ] ] bc ::=[ B bc ::=[ B C ] 
C ] ]
+  Second derivation    s ::=[ ac ::=[ A ac ::=[ A ac ::=[ b ::=[ . b ::=[ B B 
] ] ] C ] C ] ]
+
 input.y:6.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -328,6 +333,11 @@ Shift/reduce conflict on token B:
   First derivation     s ::=[ n ::=[ N a ::=[ A . ] B ] C ]
   Second derivation    s ::=[ n ::=[ N b ::=[ A . B C ] ] ]
 
+Shift/reduce conflict on token B:
+  Example              N N A . B D C
+  First derivation     s ::=[ n ::=[ N n ::=[ N a ::=[ A . ] B ] D ] C ]
+  Second derivation    s ::=[ n ::=[ N n ::=[ N b ::=[ A . B D ] ] C ] ]
+
 input.y:5.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
diff --git a/tests/diagnostics.at b/tests/diagnostics.at
index 6d3ead97..17a2ebc5 100644
--- a/tests/diagnostics.at
+++ b/tests/diagnostics.at
@@ -545,6 +545,12 @@ Shift/reduce conflict on token "else":
   Example              <cex-0><cex-leaf>"if"</cex-leaf> 
<cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf><cex-1> 
<cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> 
<cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"else"</cex-leaf> 
<cex-leaf>exp</cex-leaf></cex-1></cex-0>
   Second derivation    <cex-0><cex-step>exp ::=[ 
</cex-step><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> 
<cex-leaf>"then"</cex-leaf><cex-1> <cex-step>exp ::=[ 
</cex-step><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> 
<cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> 
<cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf><cex-step> 
]</cex-step></cex-1><cex-step> ]</cex-step></cex-0>
 
+Shift/reduce conflict on token "+":
+  Example              <cex-0><cex-1><cex-leaf>"if"</cex-leaf> 
<cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> 
<cex-dot>•</cex-dot></cex-1> <cex-leaf>"+"</cex-leaf> 
<cex-leaf>exp</cex-leaf></cex-0>
+  First derivation     <cex-0><cex-step>exp ::=[ 
</cex-step><cex-1><cex-step>exp ::=[ </cex-step><cex-leaf>"if"</cex-leaf> 
<cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> 
<cex-dot>•</cex-dot><cex-step> ]</cex-step></cex-1> <cex-leaf>"+"</cex-leaf> 
<cex-leaf>exp</cex-leaf><cex-step> ]</cex-step></cex-0>
+  Example              <cex-0><cex-leaf>"if"</cex-leaf> 
<cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf><cex-1> 
<cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"+"</cex-leaf> 
<cex-leaf>exp</cex-leaf></cex-1></cex-0>
+  Second derivation    <cex-0><cex-step>exp ::=[ 
</cex-step><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> 
<cex-leaf>"then"</cex-leaf><cex-1> <cex-step>exp ::=[ 
</cex-step><cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> 
<cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf><cex-step> 
]</cex-step></cex-1><cex-step> ]</cex-step></cex-0>
+
 Shift/reduce conflict on token "+":
   Example              <cex-0><cex-1><cex-leaf>"if"</cex-leaf> 
<cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> 
<cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf> 
<cex-dot>•</cex-dot></cex-1> <cex-leaf>"+"</cex-leaf> 
<cex-leaf>exp</cex-leaf></cex-0>
   First derivation     <cex-0><cex-step>exp ::=[ 
</cex-step><cex-1><cex-step>exp ::=[ </cex-step><cex-leaf>"if"</cex-leaf> 
<cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> 
<cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf> 
<cex-dot>•</cex-dot><cex-step> ]</cex-step></cex-1> <cex-leaf>"+"</cex-leaf> 
<cex-leaf>exp</cex-leaf><cex-step> ]</cex-step></cex-0>
diff --git a/tests/report.at b/tests/report.at
index 1d93f9a5..3801c919 100644
--- a/tests/report.at
+++ b/tests/report.at
@@ -1190,6 +1190,16 @@ Shift/reduce conflict on token "⊕":
   First derivation     exp ::=[ exp ::=[ exp "⊕" exp • ] "⊕" exp ]
   Second derivation    exp ::=[ exp "⊕" exp ::=[ exp • "⊕" exp ] ]
 
+Shift/reduce conflict on token "+":
+  Example              exp "⊕" exp • "+" exp
+  First derivation     exp ::=[ exp ::=[ exp "⊕" exp • ] "+" exp ]
+  Second derivation    exp ::=[ exp "⊕" exp ::=[ exp • "+" exp ] ]
+
+Shift/reduce conflict on token "+":
+  Example              exp "⊕" exp • "+" exp
+  First derivation     exp ::=[ exp ::=[ exp "⊕" exp • ] "+" exp ]
+  Second derivation    exp ::=[ exp "⊕" exp ::=[ exp • "+" exp ] ]
+
 input.y:6.3-13: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -1377,6 +1387,20 @@ State 8
       First derivation         exp ::=[ exp ::=[ exp "⊕" exp • ] "⊕" exp ]
       Second derivation        exp ::=[ exp "⊕" exp ::=[ exp • "⊕" exp ] ]
 
+    Shift/reduce conflict on token "+":
+        1 exp: exp "⊕" exp •
+        2 exp: exp • "+" exp
+      Example                  exp "⊕" exp • "+" exp
+      First derivation         exp ::=[ exp ::=[ exp "⊕" exp • ] "+" exp ]
+      Second derivation        exp ::=[ exp "⊕" exp ::=[ exp • "+" exp ] ]
+
+    Shift/reduce conflict on token "+":
+        1 exp: exp "⊕" exp •
+        3 exp: exp • "+" exp
+      Example                  exp "⊕" exp • "+" exp
+      First derivation         exp ::=[ exp ::=[ exp "⊕" exp • ] "+" exp ]
+      Second derivation        exp ::=[ exp "⊕" exp ::=[ exp • "+" exp ] ]
+
 ]])