improved error messages

lang/cem/cemcom/expr.c

@@ -171,7 +171,7 @@ idf2expr(expr)
 			add_def(idf, IMPLICIT, funint_type, level); /* RM 13 */
 		else	{
 			if (!is_anon_idf(idf))
-				error("%s undefined", idf->id_text);
+				error("identifier %s undefined", idf->id_text);
 			/* declare idf anyway */
 			add_def(idf, 0, error_type, level);
 		}

lang/cem/cemcom/l_lint.c

@@ -288,8 +288,10 @@ expr_ignored(expr)
 	struct expr *expr;
 {
 	switch (expr->ex_class) {
+		int oper;
 	case Oper:
-		switch (expr->OP_OPER) {
+		oper = expr->OP_OPER;
+		switch (oper) {
 		case '=':
 		case TIMESAB:
 		case DIVAB:
@@ -304,6 +306,7 @@ expr_ignored(expr)
 		case '(':
 		case '?':
 		case ',':
+			oper = 0;		/* ignore the ignoring */
 			break;
 
 		case PLUSAB:
@@ -312,21 +315,32 @@ expr_ignored(expr)
 		case POSTDECR:
 		case PLUSPLUS:
 		case MINMIN:
-			/* may hide the operator '*' */
+			oper = 0;		/* ignore in priciple */
+			/* may, however, hide the operator '*' */
 			if (	/* operation on a pointer */
 				expr->OP_TYPE->tp_fund == POINTER
 			&&	/* the result is dereferenced, e.g. *p++; */
 				expr->ex_type == expr->OP_TYPE->tp_up
 			) {
-				hwarning("result of * ignored");
+				oper = '*';
 			}
 			break;
 
-		default:
-			hwarning("result of %s ignored",
-						symbol2str(expr->OP_OPER));
+		case '/':
+			/*	this is a specially weird case: the '/' may
+				result from pointer subtraction
+			*/
+			if (	expr->OP_TYPE->tp_fund == INT
+			&&	expr->OP_LEFT->OP_OPER == '-'
+			&&	expr->OP_LEFT->OP_TYPE->tp_fund == POINTER
+			) {
+				oper = '-';
+			}
 			break;
 		}
+		if (oper) {
+			hwarning("result of %s ignored", symbol2str(oper));
+		}
 		break;
 
 	case Value:

lang/cem/cemcom/l_states.c

@@ -151,7 +151,7 @@ lint_1_local(idf, def)
 	&&	!def->df_used
 	&&	!is_anon_idf(idf)
 	) {
-		def_warning(def, "%s %s not used anywhere in function %s",
+		def_warning(def, "%s %s not applied anywhere in function %s",
 			symbol2str(sc), idf->id_text, func_name);
 	}
 
@@ -309,7 +309,8 @@ change_state(idf, to_state)
 	case USED:
 		if (!a->ad_set) {
 			if (!is_anon_idf(idf)) {
-				warning("%s%s uninitialized", idf->id_text,
+				warning("variable %s%s uninitialized",
+					idf->id_text,
 					(a->ad_maybe_set ? " possibly" : "")
 				);
 			}
@@ -342,7 +343,7 @@ add_auto(idf)	/* to current state on top of lint_stack */
 		a = new_auto_def();
 
 		a->ad_idf = idf;
-		a->ad_def = idf->id_def;
+		a->ad_def = def;
 		a->ad_used = def->df_used;
 		a->ad_set = def->df_set;
 
@@ -361,16 +362,19 @@ check_autos()
 
 	ASSERT(!(a && a->ad_def->df_level > level));
 	while (a && a->ad_def->df_level == level) {
-		if (!a->ad_used && !is_anon_idf(a->ad_idf)) {
-			if (a->ad_set || a->ad_maybe_set) {
-				def_warning(a->ad_def,
+		struct idf *idf = a->ad_idf;
+		struct def *def = idf->id_def;
+
+		if (!def->df_used && !is_anon_idf(idf)) {
+			if (def->df_set || a->ad_maybe_set) {
+				def_warning(def,
 					"%s set but not used in function %s",
-					a->ad_idf->id_text, func_name);
+					idf->id_text, func_name);
 			}
 			else {
-				def_warning(a->ad_def,
+				def_warning(def,
 					"%s not used anywhere in function %s",
-					a->ad_idf->id_text, func_name);
+					idf->id_text, func_name);
 			}
 		}
 
@@ -1216,6 +1220,24 @@ lint_pop()
 #ifdef	DEBUG
 /* FOR DEBUGGING */
 
+PRIVATE
+print_autos(a)
+	struct auto_def *a;
+{
+	while (a) {
+		struct idf *idf = a->ad_idf;
+		struct def *def = idf->id_def;
+
+		print("%s", idf->id_text);
+		print("(lvl=%d)", a->ad_def->df_level);
+		print("(u%ds%dm%d U%dS%d) ",
+			a->ad_used, a->ad_set, a->ad_maybe_set,
+			def->df_used, def->df_set
+		);
+		a = a->next;
+	}
+}
+
 PRIVATE
 pr_lint_state(nm, st)
 	char *nm;
@@ -1241,7 +1263,7 @@ print_lint_stack(msg)
 	while (lse) {
 		print("  |-------------- level %d ------------\n",
 					lse->ls_level);
-		pr_lint_state("  |cur", lse->ls_current);
+		pr_lint_state("  |current", lse->ls_current);
 
 		print("  |class == %s\n",
 			lse->ls_class ? symbol2str(lse->ls_class) : "{");
@@ -1277,16 +1299,6 @@ print_lint_stack(msg)
 	print("  |--------------\n\n");
 }
 
-print_autos(a)
-	register struct auto_def *a;
-{
-	while (a) {
-		print("%s", a->ad_idf->id_text);
-		print("(lvl=%d)", a->ad_def->df_level);
-		print("(U%dS%dM%d) ", a->ad_used, a->ad_set, a->ad_maybe_set);
-		a = a->next;
-	}
-}
 #endif	DEBUG
 
 #endif	LINT