diff --git a/tool/cmd/validate.c b/tool/cmd/validate.c
index 1966e30..51b6bf0 100644
--- a/tool/cmd/validate.c
+++ b/tool/cmd/validate.c
@@ -1,3 +1,4 @@
+#include "../diag/diag.h"
 #include "cmd.h"
 
 #include <assert.h>
@@ -26,6 +27,7 @@
 #include <mie/ir/walk.h>
 #include <mie/name.h>
 #include <mie/parse/lex.h>
+#include <mie/parse/line-source.h>
 #include <mie/parse/parser.h>
 #include <mie/parse/token.h>
 #include <mie/pass/builtin.h>
@@ -68,7 +70,10 @@ static int validate_file(const char *path, const b_arglist *args)
 
 	mie_builtin_passes_register(ctx);
 
-	struct mie_lex *lex = mie_lex_create(file);
+	struct mie_line_source src;
+	mie_line_source_init(&src, path, file);
+
+	struct mie_lex *lex = mie_lex_create(&src, ctx);
 	struct mie_parser *parse = mie_parser_create(ctx, lex);
 
 	struct mie_name_map *names = mie_name_map_create(NULL);
@@ -76,6 +81,13 @@ static int validate_file(const char *path, const b_arglist *args)
 	struct mie_op *root = mie_op_create();
 
 	if (!mie_parser_parse_op(parse, NULL, root)) {
+		struct mie_diag *diag = mie_ctx_pop_diag(ctx);
+		while (diag) {
+			mie_diag_write_pretty(diag, b_stdtty_err);
+			/* TODO cleanup */
+			diag = mie_ctx_pop_diag(ctx);
+		}
+
 		printf("parse failed\n");
 		return -1;
 	}
@@ -215,6 +227,8 @@ static int validate_file(const char *path, const b_arglist *args)
 
 	mie_lex_destroy(lex);
 
+	mie_line_source_cleanup(&src);
+
 	b_file_unref(file);
 
 	return 0;