Use -Wimplicit-int when warning about missing K&R argument types

In legacy environment, a lot of warnings can be issued about
arguments without an explicit type.

Fix this by contitionalizing such warnings with the flag
-Wimplicit-int, reducing the level of noise in such environment.

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>

4 files changed, 22 insertions, 1 deletions

diff --git a/lib.c b/lib.c
index 81820745..314b65e9 100644
--- a/lib.c
+++ b/lib.c
@@ -262,6 +262,7 @@ int Wdeclarationafterstatement = -1;
 int Wdefault_bitfield_sign = 0;
 int Wdesignated_init = 1;
 int Wdo_while = 0;
+int Wimplicit_int = 1;
 int Winit_cstring = 0;
 int Wint_to_pointer_cast = 1;
 int Wenum_mismatch = 1;
@@ -700,6 +701,7 @@ static const struct flag warnings[] = {
 	{ "designated-init", &Wdesignated_init },
 	{ "do-while", &Wdo_while },
 	{ "enum-mismatch", &Wenum_mismatch },
+	{ "implicit-int", &Wimplicit_int },
 	{ "init-cstring", &Winit_cstring },
 	{ "int-to-pointer-cast", &Wint_to_pointer_cast },
 	{ "memcpy-max-count", &Wmemcpy_max_count },
diff --git a/lib.h b/lib.h
index 14b13b67..bd578be5 100644
--- a/lib.h
+++ b/lib.h
@@ -152,6 +152,7 @@ extern int Wdesignated_init;
 extern int Wdo_while;
 extern int Wenum_mismatch;
 extern int Wsparse_error;
+extern int Wimplicit_int;
 extern int Winit_cstring;
 extern int Wint_to_pointer_cast;
 extern int Wmemcpy_max_count;
diff --git a/parse.c b/parse.c
index 7f15acf5..ec145601 100644
--- a/parse.c
+++ b/parse.c
@@ -2770,7 +2770,10 @@ static void apply_k_r_types(struct symbol_list *argtypes, struct symbol *fn)
 			if (type->ident == arg->ident)
 				goto match;
 		} END_FOR_EACH_PTR(type);
-		sparse_error(arg->pos, "missing type declaration for parameter '%s'", show_ident(arg->ident));
+		if (Wimplicit_int) {
+			sparse_error(arg->pos, "missing type declaration for parameter '%s'",
+				show_ident(arg->ident));
+		}
 		type = alloc_symbol(arg->pos, SYM_NODE);
 		type->ident = arg->ident;
 		type->ctype.base_type = &int_ctype;
diff --git a/validation/implicit-KR-arg-type0.c b/validation/implicit-KR-arg-type0.c
new file mode 100644
index 00000000..f73d36ff
--- /dev/null
+++ b/validation/implicit-KR-arg-type0.c
@@ -0,0 +1,15 @@
+int foo(a, b)
+	int a;
+{
+	if (b)
+		return a;
+}
+
+/*
+ * check-name: implicit-KR-arg-type
+ * check-command: sparse -Wno-decl -Wold-style-definition -Wno-implicit-int $file
+ *
+ * check-error-start
+implicit-KR-arg-type0.c:2:9: warning: non-ANSI definition of function 'foo'
+ * check-error-end
+ */