cex: suggest -Wcounterexamples when there are unexpected conflicts

Suggesting -Wcounterexamples when there are conflicts is probably not
what the user wants.  If she knows her conflicts and has set
%expect/%expect-rr appropriately, we shouldn't warn.

The commit also swaps the counterexamples and the report of conflicts,
into, IMHO, a more natural order: from

    Shift/reduce conflict on token B:
    1:    3 a: A .
    1:    8 y: A . B
    Example              A • B C
    First derivation     s ::=[ a ::=[ A • ] x ::=[ B C ] ]
    Example              A • B C
    Second derivation    s ::=[ y ::=[ A • B ] c ::=[ C ] ]

    input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
    input.y:4.4: warning: rule useless in parser due to conflicts [-Wother]

to

    input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
    Shift/reduce conflict on token B:
    1:    3 a: A .
    1:    8 y: A . B
    Example              A • B C
    First derivation     s ::=[ a ::=[ A • ] x ::=[ B C ] ]
    Example              A • B C
    Second derivation    s ::=[ y ::=[ A • B ] c ::=[ C ] ]

    input.y:4.4: warning: rule useless in parser due to conflicts [-Wother]

* src/conflicts.c (rule_conflicts_print): Rename as...
(report_rule_expectation_mismatches): this.
Move the handling of report_counterexamples to...
(conflicts_print): Here.
Display this warning when applicable.

1 files changed, 17 insertions, 0 deletions

diff --git a/tests/glr-regression.at b/tests/glr-regression.at
index 8257088b..fede248d 100644
--- a/tests/glr-regression.at
+++ b/tests/glr-regression.at
@@ -89,6 +89,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr1.c -rall glr-regr1.y]], 0, [],
 [[glr-regr1.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+glr-regr1.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr1])
 AT_PARSER_CHECK([[glr-regr1 BPBPB]], 0,
@@ -213,6 +214,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr2a.c -rall glr-regr2a.y]], 0, [],
 [[glr-regr2a.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
+glr-regr2a.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr2a])
 
@@ -348,6 +350,7 @@ AT_BISON_OPTION_POPDEFS
 AT_BISON_CHECK([[-o glr-regr3.c -rall glr-regr3.y]], 0, [],
 [[glr-regr3.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 glr-regr3.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
+glr-regr3.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr3])
 
@@ -444,6 +447,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr4.c -rall glr-regr4.y]], 0, [],
 [[glr-regr4.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
+glr-regr4.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr4])
 
@@ -501,6 +505,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr5.c -rall glr-regr5.y]], 0, [],
 [[glr-regr5.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+glr-regr5.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr5])
 
@@ -550,6 +555,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr6.c -rall glr-regr6.y]], 0, [],
 [[glr-regr6.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+glr-regr6.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr6])
 
@@ -640,6 +646,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr7.c -rall glr-regr7.y]], 0, [],
 [[glr-regr7.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
+glr-regr7.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr7])
 
@@ -730,6 +737,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr8.c -rall glr-regr8.y]], 0, [],
 [[glr-regr8.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+glr-regr8.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr8])
 
@@ -811,6 +819,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr9.c -rall glr-regr9.y]], 0, [],
 [[glr-regr9.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
+glr-regr9.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr9])
 
@@ -868,6 +877,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr10.c -rall glr-regr10.y]], 0, [],
 [[glr-regr10.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+glr-regr10.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr10])
 
@@ -927,6 +937,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr11.c -rall glr-regr11.y]], 0, [],
 [[glr-regr11.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+glr-regr11.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr11])
 
@@ -1049,6 +1060,7 @@ AT_BISON_OPTION_POPDEFS
 AT_BISON_CHECK([[-o glr-regr12.c -rall glr-regr12.y]], 0, [],
 [[glr-regr12.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 glr-regr12.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+glr-regr12.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr12])
 
@@ -1380,6 +1392,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr14.c -rall glr-regr14.y]], 0, [],
 [[glr-regr14.y: warning: 5 reduce/reduce conflicts [-Wconflicts-rr]
+glr-regr14.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr14])
 
@@ -1474,6 +1487,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr15.c -rall glr-regr15.y]], 0, [],
 [[glr-regr15.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
+glr-regr15.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr15])
 
@@ -1535,6 +1549,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr16.c -rall glr-regr16.y]], 0, [],
 [[glr-regr16.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+glr-regr16.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr16])
 
@@ -1610,6 +1625,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr17.c -rall glr-regr17.y]], 0, [],
 [[glr-regr17.y: warning: 3 reduce/reduce conflicts [-Wconflicts-rr]
+glr-regr17.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr17])
 
@@ -1703,6 +1719,7 @@ d: /* nada.  */;
 
 AT_BISON_CHECK([[-o input.c input.y]], 0, [],
 [[input.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([input])