3 files changed, 22 insertions, 8 deletions
diff --git a/evaluate.c b/evaluate.c
index 65e5d5a2..e4391941 100644
--- a/evaluate.c
+++ b/evaluate.c
@@ -542,13 +542,24 @@ const char * type_difference(struct symbol *target, struct symbol *source,
 			if (diff & ~MOD_SIGNEDNESS)
 				return "different modifiers";
 
-			/* Differs in signedness only.. Sometimes ok - but not if both are explicit */
-			if ((mod1 | mod2) & MOD_EXPLICITLY_SIGNED)
-				return "different explicit signedness";
-
-			/* "char" matches both "unsigned char" and "signed char" */
-			if (!(mod1 & MOD_CHAR))
-				return "different signedness";
+			/* Differs in signedness only.. */
+			if (Wtypesign) {
+				/*
+				 * Warn if both are explicitly signed ("unsigned" is obvously
+				 * always explicit, and since we know one of them has to be
+				 * unsigned, we check if the signed one was explicit).
+				 */
+				if ((mod1 | mod2) & MOD_EXPLICITLY_SIGNED)
+					return "different explicit signedness";
+
+				/*
+				 * "char" matches both "unsigned char" and "signed char",
+				 * so if the explicit test didn't trigger, then we should
+				 * not warn about a char.
+				 */
+				if (!(mod1 & MOD_CHAR))
+					return "different signedness";
+			}
 		}
 
 		if (type1 == SYM_FN) {
diff --git a/lib.c b/lib.c
index a2c3c2c4..5d15706f 100644
--- a/lib.c
+++ b/lib.c
@@ -561,6 +561,7 @@ unsigned char pre_buffer[8192];
 
 int Wdefault_bitfield_sign = 0;
 int Wbitwise = 0;
+int Wtypesign = 0;
 int preprocess_only;
 char *include;
 int include_fd = -1;
@@ -669,7 +670,8 @@ struct warning {
 	int *flag;
 } warnings[] = {
 	{ "default-bitfield-sign", &Wdefault_bitfield_sign },
-	{ "bitwise", &Wbitwise }
+	{ "bitwise", &Wbitwise },
+	{ "typesign", &Wtypesign },
 };
 
 
diff --git a/lib.h b/lib.h
index fb5db185..bcbcab04 100644
--- a/lib.h
+++ b/lib.h
@@ -139,6 +139,7 @@ extern char *include;
 extern int preprocess_only;
 extern int Wdefault_bitfield_sign;
 extern int Wbitwise;
+extern int Wtypesign;
 
 extern void create_builtin_stream(void);