fix(gen): -x/~x 对编译期常量折叠，修负字面量被隐式窄化误拦

App/lib/core/Gen/Expr/ExprGenOps.vp

@@ -569,9 +569,16 @@ novirtual class ExprGenOps(ExprGenBase.ExprGenBase):
             # -x
             # Float type uses fneg (emit fneg directly to avoid 0.0 - x type mismatch)
             operand_fbits: int = self.get_llvm_float_bits(operand.Ty)
-            if operand_fbits > 0: return mlirlite.build_fneg(builder, operand)
-            # Integer: -x = 0 - x, choosing the zero constant by bit width (avoid i32/i64 mismatch)
+            if operand_fbits > 0:
+                # 编译期常量折叠：-c 直接产出常量并保持 IsConst
+                if operand.IsConst == 1: return mlirlite.ConstFloat(pool, operand.Ty, -operand.FloatVal)
+                return mlirlite.build_fneg(builder, operand)
+            # 编译期常量折叠：-c 直接产出常量（IsConst=1）。否则 `v: int8 = -50` 会被当成运行时 i32 值，
+            # 触发“隐式窄化禁止”，尽管其数值完全落在 i8 内（隐式窄化的“编译期常量”豁免失效）。
             operand_bits: int = self.get_llvm_type_bits(operand.Ty)
+            if operand_bits != 0 and operand.IsConst == 1:
+                return mlirlite.const_int(pool, operand_bits, -operand.IntVal)
+            # Integer: -x = 0 - x, choosing the zero constant by bit width (avoid i32/i64 mismatch)
             zero: mlirlite.Value* = mlirlite.const_int32(pool, 0)
             if operand_bits == 64: zero = mlirlite.const_int64(pool, 0)
             elif operand_bits > 0 and operand_bits != 32:
@@ -590,6 +597,9 @@ novirtual class ExprGenOps(ExprGenBase.ExprGenBase):
         elif uo.op == ast.OpKind.Invert:
             # ~x = x ^ -1
             operand_bits_inv: int = self.get_llvm_type_bits(operand.Ty)
+            # 编译期常量折叠：~c 直接产出常量并保持 IsConst（与 -c 相同的窄化豁免口径）
+            if operand_bits_inv != 0 and operand.IsConst == 1:
+                return mlirlite.const_int(pool, operand_bits_inv, operand.IntVal ^ -1)
             neg1: mlirlite.Value* = mlirlite.const_int32(pool, -1)
             if operand_bits_inv == 64: neg1 = mlirlite.const_int64(pool, -1)
             return mlirlite.build_xor(builder, operand, neg1)