Silence -Wmatch-empty-string on trivial obviously nullable cases.

skvadrik · Sep 10, 2020 · ee125da · ee125da
1 parent 960f881
commit ee125da
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Showing 80 changed files with 42 additions and 93 deletions.
diff --git a/examples/c/conditions/parse_u32_blocks.c b/examples/c/conditions/parse_u32_blocks.c
@@ -242,4 +242,3 @@ int main()
     assert(parse_u32("") == ERROR);
     return 0;
 }
-c/conditions/parse_u32_blocks.re:29:23: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/examples/c/conditions/parse_u32_conditions.c b/examples/c/conditions/parse_u32_conditions.c
@@ -250,4 +250,3 @@ int main()
     assert(parse_u32("") == ERROR);
     return 0;
 }
-c/conditions/parse_u32_conditions.re:33:30: warning: rule in condition 'init' matches empty string [-Wmatch-empty-string]
diff --git a/examples/c/real_world/cxx98.c b/examples/c/real_world/cxx98.c
@@ -8349,7 +8349,4 @@ int main()
     remove(fname);
     return 0;
 }
-c/real_world/cxx98.re:152:14: warning: rule matches empty string [-Wmatch-empty-string]
 c/real_world/cxx98.re:158:14: warning: rule matches empty string [-Wmatch-empty-string]
-c/real_world/cxx98.re:163:14: warning: rule matches empty string [-Wmatch-empty-string]
-c/real_world/cxx98.re:349:24: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/examples/go/conditions/parse_u32_blocks.go b/examples/go/conditions/parse_u32_blocks.go
diff --git a/examples/go/conditions/parse_u32_conditions.go b/examples/go/conditions/parse_u32_conditions.go
diff --git a/src/regexp/nullable.cc b/src/regexp/nullable.cc
@@ -92,6 +92,21 @@ static bool nullable(const RESpec &spec, std::vector<StackItem> &stack, const RE
     return null;
 }
 
+static bool trivially_nullable(const RESpec &spec, const RE *re)
+{
+    // "" { ... }
+    if (re->type == RE::NIL) return true;
+
+    // "" / ... { ... }
+    if (re->type == RE::CAT
+        && re->cat.re1->type == RE::NIL
+        && re->cat.re2->type == RE::CAT
+        && re->cat.re2->cat.re1->type == RE::TAG
+        && trailing(spec.tags[re->cat.re2->cat.re1->tag.idx])) return true;
+
+    return false;
+}
+
 } // anonymous namespace
 
 // Warn about rules that match empty string (including rules with nonempty
@@ -104,7 +119,12 @@ void warn_nullable(const RESpec &spec, const std::string &cond)
     std::vector<StackItem> stack;
     const size_t nre = spec.res.size();
     for (size_t i = 0; i < nre; ++i) {
-        if (nullable(spec, stack, spec.res[i])) {
+        const RE *re = spec.res[i];
+        if (trivially_nullable(spec, re)) {
+            // Exclude trivial obviously nullable cases like "", as they are
+            // often used as a non-consuming default rule. This also captures
+            // empty character classes, but they are covered by another warning.
+        } else if (nullable(spec, stack, re)) {
             spec.msg.warn.match_empty_string(spec.rules[i].semact->loc, cond);
         }
     }

diff --git a/test/bug116.c b/test/bug116.c
@@ -21,5 +21,4 @@
 }
 #line 4 "bug116.re"
 
-bug116.re:3:13: warning: rule matches empty string [-Wmatch-empty-string]
 bug116.re:4:2: warning: control flow is undefined for strings that match '[\x0-\x60\x62-\xFF]', use default rule '*' [-Wundefined-control-flow]
diff --git a/test/bug119.c b/test/bug119.c
@@ -9,4 +9,3 @@
 yy0:
 	{}
 
-bug119.re:3:7: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug119_abort.c b/test/bug119_abort.c
@@ -13,4 +13,3 @@
 	{}
 }
 
-bug119_abort.re:4:7: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug119_abort_bif.c b/test/bug119_abort_bif.c
@@ -11,4 +11,3 @@
 yy0:
 	{}
 
-bug119_abort_bif.re:4:7: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug119_abort_if.c b/test/bug119_abort_if.c
@@ -11,4 +11,3 @@
 yy0:
 	{}
 
-bug119_abort_if.re:4:7: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug119_gif.c b/test/bug119_gif.c
@@ -11,4 +11,3 @@
 	{}
 }
 
-bug119_gif.re:3:7: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug119_if.c b/test/bug119_if.c
@@ -9,4 +9,3 @@
 yy0:
 	{}
 
-bug119_if.re:3:7: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug46_infinite_loop.c b/test/bug46_infinite_loop.c
@@ -52,5 +52,4 @@ int main(int argc, char** argv)
     printf("exit 1\n");
     return 0;
 }
-bug46_infinite_loop.re:14:4: warning: rule matches empty string [-Wmatch-empty-string]
 bug46_infinite_loop.re:19:13: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug61_difference_full.c b/test/bug61_difference_full.c
@@ -7,4 +7,3 @@
 }
 
 bug61_difference_full.re:3:4: warning: empty character class [-Wempty-character-class]
-bug61_difference_full.re:3:28: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug61_difference_full_i.c b/test/bug61_difference_full_i.c
@@ -7,4 +7,3 @@
 }
 
 bug61_difference_full_i.re:3:4: warning: empty character class [-Wempty-character-class]
-bug61_difference_full_i.re:3:28: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug61_difference_negative_i.c b/test/bug61_difference_negative_i.c
@@ -7,4 +7,3 @@
 }
 
 bug61_difference_negative_i.re:3:4: warning: empty character class [-Wempty-character-class]
-bug61_difference_negative_i.re:3:30: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug61_difference_negative_i_empty_class_match_empty.c b/test/bug61_difference_negative_i_empty_class_match_empty.c
@@ -7,4 +7,3 @@
 }
 
 bug61_difference_negative_i_empty_class_match_empty.re:3:4: warning: empty character class [-Wempty-character-class]
-bug61_difference_negative_i_empty_class_match_empty.re:3:30: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug61_difference_positive.c b/test/bug61_difference_positive.c
@@ -7,4 +7,3 @@
 }
 
 bug61_difference_positive.re:3:4: warning: empty character class [-Wempty-character-class]
-bug61_difference_positive.re:3:10: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug61_difference_positive_i.c b/test/bug61_difference_positive_i.c
@@ -7,4 +7,3 @@
 }
 
 bug61_difference_positive_i.re:3:4: warning: empty character class [-Wempty-character-class]
-bug61_difference_positive_i.re:3:10: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug61_i.c b/test/bug61_i.c
@@ -35,12 +35,7 @@
 }
 
 bug61_i.re:3:4: warning: empty character class [-Wempty-character-class]
-bug61_i.re:3:7: warning: rule matches empty string [-Wmatch-empty-string]
 bug61_i.re:7:4: warning: empty character class [-Wempty-character-class]
-bug61_i.re:7:17: warning: rule matches empty string [-Wmatch-empty-string]
 bug61_i.re:11:4: warning: empty character class [-Wempty-character-class]
-bug61_i.re:11:28: warning: rule matches empty string [-Wmatch-empty-string]
 bug61_i.re:15:4: warning: empty character class [-Wempty-character-class]
-bug61_i.re:15:10: warning: rule matches empty string [-Wmatch-empty-string]
 bug61_i.re:19:4: warning: empty character class [-Wempty-character-class]
-bug61_i.re:19:30: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug61_i_empty_class_match_empty.c b/test/bug61_i_empty_class_match_empty.c
@@ -35,12 +35,7 @@
 }
 
 bug61_i_empty_class_match_empty.re:3:4: warning: empty character class [-Wempty-character-class]
-bug61_i_empty_class_match_empty.re:3:7: warning: rule matches empty string [-Wmatch-empty-string]
 bug61_i_empty_class_match_empty.re:7:4: warning: empty character class [-Wempty-character-class]
-bug61_i_empty_class_match_empty.re:7:17: warning: rule matches empty string [-Wmatch-empty-string]
 bug61_i_empty_class_match_empty.re:11:4: warning: empty character class [-Wempty-character-class]
-bug61_i_empty_class_match_empty.re:11:28: warning: rule matches empty string [-Wmatch-empty-string]
 bug61_i_empty_class_match_empty.re:15:4: warning: empty character class [-Wempty-character-class]
-bug61_i_empty_class_match_empty.re:15:10: warning: rule matches empty string [-Wmatch-empty-string]
 bug61_i_empty_class_match_empty.re:19:4: warning: empty character class [-Wempty-character-class]
-bug61_i_empty_class_match_empty.re:19:30: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug61_negative.c b/test/bug61_negative.c
@@ -7,4 +7,3 @@
 }
 
 bug61_negative.re:3:4: warning: empty character class [-Wempty-character-class]
-bug61_negative.re:3:17: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug61_negative_i_empty_class_match_empty.c b/test/bug61_negative_i_empty_class_match_empty.c
@@ -7,4 +7,3 @@
 }
 
 bug61_negative_i_empty_class_match_empty.re:3:4: warning: empty character class [-Wempty-character-class]
-bug61_negative_i_empty_class_match_empty.re:3:17: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug61_positive.c b/test/bug61_positive.c
@@ -7,4 +7,3 @@
 }
 
 bug61_positive.re:3:4: warning: empty character class [-Wempty-character-class]
-bug61_positive.re:3:7: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/bug61_positive_i_empty_class_match_empty.c b/test/bug61_positive_i_empty_class_match_empty.c
@@ -7,4 +7,3 @@
 }
 
 bug61_positive_i_empty_class_match_empty.re:3:4: warning: empty character class [-Wempty-character-class]
-bug61_positive_i_empty_class_match_empty.re:3:7: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/encodings/default_dup_star_1.c b/test/encodings/default_dup_star_1.c
@@ -28,5 +28,4 @@
 	{ return DEFAULT-*; }
 }
 
-encodings/default_dup_star_1.re:5:9: warning: rule in condition 'c3' matches empty string [-Wmatch-empty-string]
 encodings/default_dup_star_1.re:5:9: warning: unreachable rule in condition 'c3' (shadowed by rule at line 6) [-Wunreachable-rules]
diff --git a/test/encodings/range_empty.c b/test/encodings/range_empty.c
@@ -12,4 +12,3 @@
 #line 4 "encodings/range_empty.re"
 
 encodings/range_empty.re:3:1: warning: empty character class [-Wempty-character-class]
-encodings/range_empty.re:3:4: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/encodings/range_empty_8.c b/test/encodings/range_empty_8.c
@@ -12,4 +12,3 @@
 #line 4 "encodings/range_empty_8.re"
 
 encodings/range_empty_8.re:3:1: warning: empty character class [-Wempty-character-class]
-encodings/range_empty_8.re:3:4: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/encodings/range_empty_e.c b/test/encodings/range_empty_e.c
@@ -12,4 +12,3 @@
 #line 4 "encodings/range_empty_e.re"
 
 encodings/range_empty_e.re:3:1: warning: empty character class [-Wempty-character-class]
-encodings/range_empty_e.re:3:4: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/encodings/range_empty_u.c b/test/encodings/range_empty_u.c
@@ -12,4 +12,3 @@
 #line 4 "encodings/range_empty_u.re"
 
 encodings/range_empty_u.re:3:1: warning: empty character class [-Wempty-character-class]
-encodings/range_empty_u.re:3:4: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/encodings/range_empty_w.c b/test/encodings/range_empty_w.c
@@ -12,4 +12,3 @@
 #line 4 "encodings/range_empty_w.re"
 
 encodings/range_empty_w.re:3:1: warning: empty character class [-Wempty-character-class]
-encodings/range_empty_w.re:3:4: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/encodings/range_empty_x.c b/test/encodings/range_empty_x.c
@@ -12,4 +12,3 @@
 #line 4 "encodings/range_empty_x.re"
 
 encodings/range_empty_x.re:3:1: warning: empty character class [-Wempty-character-class]
-encodings/range_empty_x.re:3:4: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/eof/eof_11_multiblock.c b/test/eof/eof_11_multiblock.c
@@ -339,4 +339,3 @@ int main()
     assert(lex("aa b cc", count) == 2);
     return 0;
 }
-eof/eof_11_multiblock.re:25:19: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/eof/shadowrule_04_hoist.c b/test/eof/shadowrule_04_hoist.c
@@ -60,6 +60,4 @@
 	{ /* EOF - here 'x' must not be set */ }
 }
 
-eof/shadowrule_04_hoist.re:6:12: warning: rule matches empty string [-Wmatch-empty-string]
 eof/shadowrule_04_hoist.re:6:12: warning: unreachable rule (shadowed by rule at line 5) [-Wunreachable-rules]
-eof/shadowrule_04_hoist.re:14:12: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/golang/009_conditions.go b/test/golang/009_conditions.go
diff --git a/test/input4.c b/test/input4.c
@@ -14,6 +14,5 @@
 #line 8 "input4.re"
 
 input4.re:4:0: warning: empty character class [-Wempty-character-class]
-input4.re:4:5: warning: rule matches empty string [-Wmatch-empty-string]
 input4.re:4:5: warning: unreachable rule (shadowed by rule at line 5) [-Wunreachable-rules]
 input4.re:6:12: warning: unreachable rule (shadowed by rule at line 5) [-Wunreachable-rules]
diff --git a/test/input4__empty_class_match_empty.c b/test/input4__empty_class_match_empty.c
@@ -14,6 +14,5 @@
 #line 8 "input4__empty_class_match_empty.re"
 
 input4__empty_class_match_empty.re:4:0: warning: empty character class [-Wempty-character-class]
-input4__empty_class_match_empty.re:4:5: warning: rule matches empty string [-Wmatch-empty-string]
 input4__empty_class_match_empty.re:4:5: warning: unreachable rule (shadowed by rule at line 5) [-Wunreachable-rules]
 input4__empty_class_match_empty.re:6:12: warning: unreachable rule (shadowed by rule at line 5) [-Wunreachable-rules]
diff --git a/test/input6.c b/test/input6.c
@@ -15,5 +15,4 @@
 
 input6.re:4:0: warning: empty character class [-Wempty-character-class]
 input6.re:4:3: warning: empty character class [-Wempty-character-class]
-input6.re:4:12: warning: rule matches empty string [-Wmatch-empty-string]
 input6.re:4:12: warning: unreachable rule (shadowed by rule at line 5) [-Wunreachable-rules]
diff --git a/test/input6__empty_class_match_empty.c b/test/input6__empty_class_match_empty.c
@@ -15,5 +15,4 @@
 
 input6__empty_class_match_empty.re:4:0: warning: empty character class [-Wempty-character-class]
 input6__empty_class_match_empty.re:4:3: warning: empty character class [-Wempty-character-class]
-input6__empty_class_match_empty.re:4:12: warning: rule matches empty string [-Wmatch-empty-string]
 input6__empty_class_match_empty.re:4:12: warning: unreachable rule (shadowed by rule at line 5) [-Wunreachable-rules]
diff --git a/test/messages/nullable.c b/test/messages/nullable.c
@@ -6,16 +6,32 @@
 	if (YYLIMIT <= YYCURSOR) YYFILL(1);
 	yych = *YYCURSOR;
 	switch (yych) {
-	case 'b':	goto yy3;
+	case 'a':	goto yy3;
+	case 'b':	goto yy6;
 	default:	goto yy2;
 	}
 yy2:
 	{}
 yy3:
+	++YYCURSOR;
+	if (YYLIMIT <= YYCURSOR) YYFILL(1);
+	yych = *YYCURSOR;
+	switch (yych) {
+	case 'a':	goto yy3;
+	case 'b':	goto yy8;
+	default:	goto yy5;
+	}
+yy5:
+	{}
+yy6:
+	++YYCURSOR;
+	YYCURSOR -= 1;
+	{}
+yy8:
 	++YYCURSOR;
 	YYCURSOR -= 1;
 	{}
 }
 
-messages/nullable.re:4:9: warning: rule matches empty string [-Wmatch-empty-string]
-messages/nullable.re:5:3: warning: rule matches empty string [-Wmatch-empty-string]
+messages/nullable.re:6:11: warning: rule matches empty string [-Wmatch-empty-string]
+messages/nullable.re:7:5: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/messages/nullable.re b/test/messages/nullable.re
@@ -3,5 +3,7 @@
 
 "" / "b" {}
 "" {}
+"a"* / "b" {}
+"a"* {}
 
 */
diff --git a/test/real_world/rexx.c b/test/real_world/rexx.c
@@ -6908,4 +6908,3 @@ bool StripToken(){
 }
 real_world/rexx.re:254:5: warning: rule matches empty string [-Wmatch-empty-string]
 real_world/rexx.re:289:0: warning: empty character class [-Wempty-character-class]
-real_world/rexx.re:290:5: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/real_world/rexx__empty_class_match_empty.c b/test/real_world/rexx__empty_class_match_empty.c
@@ -6908,4 +6908,3 @@ bool StripToken(){
 }
 real_world/rexx__empty_class_match_empty.re:254:5: warning: rule matches empty string [-Wmatch-empty-string]
 real_world/rexx__empty_class_match_empty.re:289:0: warning: empty character class [-Wempty-character-class]
-real_world/rexx__empty_class_match_empty.re:290:5: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/repeater2.c b/test/repeater2.c
@@ -357,7 +357,6 @@
 }
 #line 52 "repeater2.re"
 
-repeater2.re:3:8: warning: rule matches empty string [-Wmatch-empty-string]
 repeater2.re:8:2: warning: control flow is undefined for strings that match '[\x0-\x60\x62-\xFF]', use default rule '*' [-Wundefined-control-flow]
 repeater2.re:12:2: warning: control flow is undefined for strings that match 
 	'[\x0-\x60\x62-\xFF]'
@@ -371,7 +370,6 @@ repeater2.re:24:2: warning: control flow is undefined for strings that match
 	'\x61 [\x0-\x60\x62-\xFF]'
 	'\x61 \x61 [\x0-\x60\x62-\xFF]'
 , use default rule '*' [-Wundefined-control-flow]
-repeater2.re:27:10: warning: rule matches empty string [-Wmatch-empty-string]
 repeater2.re:31:10: warning: rule matches empty string [-Wmatch-empty-string]
 repeater2.re:36:2: warning: control flow is undefined for strings that match '[\x0-\x60\x62-\xFF]', use default rule '*' [-Wundefined-control-flow]
 repeater2.re:40:2: warning: control flow is undefined for strings that match '[\x0-\x60\x62-\xFF]', use default rule '*' [-Wundefined-control-flow]

diff --git a/test/stadfa/stadfa_01.c b/test/stadfa/stadfa_01.c
@@ -39,4 +39,3 @@
 	}
 }
 
-stadfa/stadfa_01.re:4:3: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/stadfa/stadfa_02.c b/test/stadfa/stadfa_02.c
@@ -26,5 +26,4 @@
 }
 
 stadfa/stadfa_02.re:3:10: warning: rule matches empty string [-Wmatch-empty-string]
-stadfa/stadfa_02.re:4:3: warning: rule matches empty string [-Wmatch-empty-string]
 stadfa/stadfa_02.re:4:3: warning: unreachable rule (shadowed by rule at line 3) [-Wunreachable-rules]
diff --git a/test/stadfa/stadfa_03.c b/test/stadfa/stadfa_03.c
@@ -21,5 +21,4 @@
 }
 
 stadfa/stadfa_03.re:3:9: warning: rule matches empty string [-Wmatch-empty-string]
-stadfa/stadfa_03.re:4:3: warning: rule matches empty string [-Wmatch-empty-string]
 stadfa/stadfa_03.re:4:3: warning: unreachable rule (shadowed by rule at line 3) [-Wunreachable-rules]
diff --git a/test/stadfa/stadfa_04.c b/test/stadfa/stadfa_04.c
@@ -27,4 +27,3 @@
 	{}
 }
 
-stadfa/stadfa_04.re:4:3: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/stadfa/stadfa_05.c b/test/stadfa/stadfa_05.c
@@ -24,4 +24,3 @@
 	goto yy4;
 }
 
-stadfa/stadfa_05.re:4:3: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/stadfa/stadfa_06.c b/test/stadfa/stadfa_06.c
@@ -38,4 +38,3 @@
 	goto yy4;
 }
 
-stadfa/stadfa_06.re:4:3: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/stadfa/stadfa_07.c b/test/stadfa/stadfa_07.c
@@ -36,5 +36,4 @@
 }
 
 stadfa/stadfa_07.re:4:13: warning: rule matches empty string [-Wmatch-empty-string]
-stadfa/stadfa_07.re:5:3: warning: rule matches empty string [-Wmatch-empty-string]
 stadfa/stadfa_07.re:5:3: warning: unreachable rule (shadowed by rule at line 4) [-Wunreachable-rules]
diff --git a/test/stadfa/stadfa_08.c b/test/stadfa/stadfa_08.c
@@ -40,4 +40,3 @@
 	{}
 }
 
-stadfa/stadfa_08.re:4:3: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/stadfa/stadfa_09.c b/test/stadfa/stadfa_09.c
@@ -38,4 +38,3 @@
 	goto yy6;
 }
 
-stadfa/stadfa_09.re:4:3: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/stadfa/stadfa_10.c b/test/stadfa/stadfa_10.c
@@ -56,4 +56,3 @@
 	{}
 }
 
-stadfa/stadfa_10.re:5:3: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/stadfa/stadfa_11.c b/test/stadfa/stadfa_11.c
@@ -63,5 +63,4 @@
 }
 
 stadfa/stadfa_11.re:3:9: warning: rule matches empty string [-Wmatch-empty-string]
-stadfa/stadfa_11.re:5:3: warning: rule matches empty string [-Wmatch-empty-string]
 stadfa/stadfa_11.re:5:3: warning: unreachable rule (shadowed by rule at line 3) [-Wunreachable-rules]
diff --git a/test/stadfa/stadfa_12.c b/test/stadfa/stadfa_12.c
@@ -43,4 +43,3 @@
 	}
 }
 
-stadfa/stadfa_12.re:4:3: warning: rule matches empty string [-Wmatch-empty-string]
diff --git a/test/stadfa/stadfa_13.c b/test/stadfa/stadfa_13.c
@@ -48,4 +48,3 @@
 	}
 }
 
-stadfa/stadfa_13.re:4:3: warning: rule matches empty string [-Wmatch-empty-string]