stage1 修复错误 提供类型检查

stage1/spl_stmt.c

@@ -203,6 +203,7 @@ spl_expr_result_t spl_parse_block_expr(spl_comp_t *ctx) {
             result = (spl_expr_result_t){0};
         } else {
             /* Expression — look ahead for assignment */
+            usize before = ctx->tok_idx;
             int is_assign = lookahead_is_assign(ctx);
             int saved_addr = ctx->addr_of_mode;
             if (is_assign)
@@ -210,6 +211,14 @@ spl_expr_result_t spl_parse_block_expr(spl_comp_t *ctx) {
             spl_expr_result_t expr = spl_parse_expr(ctx, PREC_MIN);
             ctx->addr_of_mode = saved_addr;
 
+            /* Safety: if no token was consumed, advance to prevent infinite loop */
+            if (ctx->tok_idx == before) {
+                advance(ctx);
+                result = (spl_expr_result_t){0};
+                skip_nl(ctx);
+                continue;
+            }
+
             skip_nl(ctx);
             if (peek(ctx)->type == TOK_SEMICOLON || peek(ctx)->type == TOK_ENDLINE) {
                 /* Expression statement: drop value, consume ; */
@@ -1140,6 +1149,7 @@ void spl_parse_stmt(spl_comp_t *ctx) {
         parse_extern_decl(ctx);
         break;
     default:
+        snprintf(ctx->parse_context, sizeof(ctx->parse_context), "expression statement");
         parse_expr_stmt(ctx);
         break;
     }