lang: ast: add diag for do keyword in inline for-loop

lang/ast/for.c

@@ -81,6 +81,27 @@ static struct token_parse_result parse_do(
 		= parser_get_state(ctx, struct for_parser_state);
 
 	if (state->s_inline) {
+		struct ivy_diag *diag = parser_push_diag(
+			ctx, IVY_LANG_E_INCORRECT_INLINE_FOR_LOOP,
+			IVY_LANG_MSG_DO_UNEXPECTED_IN_INLINE_FOR, tok);
+		ivy_diag_push_msg(
+			diag, IVY_LANG_MSG_PREVIOUS_EXPRESSION_IS_FOR_BODY);
+		const struct ivy_char_cell *x = &state->s_body->n_end;
+		const struct ivy_char_cell *z = &tok->t_end;
+
+		const struct ivy_diag_amendment a[] = {
+			IVY_DIAG_ADD(x->c_row, x->c_col + 1, "."),
+		};
+		const size_t nr_a = sizeof a / sizeof a[0];
+
+		const struct ivy_diag_highlight hl[] = {
+			IVY_DIAG_HL(
+				HINT, x->c_row, x->c_col + 1, x->c_row,
+				x->c_col + 1),
+		};
+		const size_t nr_hl = sizeof hl / sizeof hl[0];
+
+		ivy_diag_push_snippet(diag, x->c_row, z->c_row, a, nr_a, hl, nr_hl);
 		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
 	}