dfilter: Improve error location for expressions

Try to underline the whole expression instead of the
token.

epan/dfilter/semcheck.c

@@ -1265,8 +1265,8 @@ check_arithmetic_expr(dfwork_t *dfw, stnode_t *st_node, ftenum_t lhs_ftype)
 	}
 
 	if (!compatible_ftypes(ftype1, ftype2)) {
-		FAIL(dfw, st_arg2, "%s and %s are not type compatible.",
-			stnode_todisplay(st_arg1), stnode_todisplay(st_arg2));
+		FAIL(dfw, st_node, "%s and %s are not compatible.",
+			ftype_name(ftype1), ftype_name(ftype2));
 	}
 
 	return ftype1;

epan/dfilter/sttype-op.c

@@ -278,6 +278,7 @@ sttype_oper_set1(stnode_t *node, stnode_op_t op, stnode_t *val1)
 	oper->op = op;
 	oper->val1 = val1;
 	oper->val2 = NULL;
+	node->location = stnode_merge_location(node, val1, (stnode_t *)NULL);
 }
 
 void
@@ -290,6 +291,7 @@ sttype_oper_set2(stnode_t *node, stnode_op_t op, stnode_t *val1, stnode_t *val2)
 	oper->op = op;
 	oper->val1 = val1;
 	oper->val2 = val2;
+	node->location = stnode_merge_location(node, val1, val2, (stnode_t *)NULL);
 }
 
 void
@@ -303,6 +305,7 @@ sttype_oper_set1_args(stnode_t *node, stnode_t *val1)
 	ws_assert(num_operands(oper->op) == 1);
 	oper->val1 = val1;
 	oper->val2 = NULL;
+	node->location = stnode_merge_location(node, val1, (stnode_t *)NULL);
 }
 
 void
@@ -316,6 +319,7 @@ sttype_oper_set2_args(stnode_t *node, stnode_t *val1, stnode_t *val2)
 	ws_assert(num_operands(oper->op) == 2);
 	oper->val1 = val1;
 	oper->val2 = val2;
+	node->location = stnode_merge_location(node, val1, val2, (stnode_t *)NULL);
 }
 
 void

epan/dfilter/syntax-tree.c

@@ -250,6 +250,37 @@ stnode_location(stnode_t *node)
 	return node->location;
 }
 
+/* Finds the first and last location from a set and creates
+ * a new location from start of first (col_start) to end of
+ * last (col_start + col_len). */
+df_loc_t
+stnode_merge_location(stnode_t *st, ...)
+{
+	df_loc_t first, last, loc;
+	df_loc_t result;
+	va_list ap;
+
+	first = last = stnode_location(st);
+
+	va_start(ap, st);
+	while ((st = va_arg(ap, stnode_t *)) != NULL) {
+		loc = stnode_location(st);
+		if (loc.col_start >= 0) {
+			if (loc.col_start < first.col_start) {
+				first = loc;
+			}
+			else if (loc.col_start > last.col_start) {
+				last = loc;
+			}
+		}
+	}
+	va_end(ap);
+
+	result.col_start = first.col_start;
+	result.col_len = last.col_start - first.col_start + last.col_len;
+	return result;
+}
+
 #define IS_OPERATOR(node) \
 	(stnode_type_id(node) == STTYPE_TEST || \
 		stnode_type_id(node) == STTYPE_ARITHMETIC)

epan/dfilter/syntax-tree.h

@@ -156,6 +156,9 @@ stnode_token(stnode_t *node);
 df_loc_t
 stnode_location(stnode_t *node);
 
+df_loc_t
+stnode_merge_location(stnode_t *n1, ...);
+
 const char *
 stnode_tostr(stnode_t *node, gboolean pretty);