fix(gen): 值语义聚合槽允许隐式值拷贝，修 self.field = param 的 Foo* -> Foo 误报

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

@@ -455,7 +455,7 @@ novirtual class ExprGenBase:
         if callee is None: return None
         ent: GenTypes.StructEntry* = self.Gen.StructGen.find_struct(callee)
         if ent is not None and ent.Ty is not None: return ent.Ty
-        # REnum variant ctor `EnumType.Variant(...)`: the callee is not a struct
+        # REnum variant ctor `EnumType.Variant(...)`: the callee is not a struct
         # name, but materializes the base enum, so return that aggregate type.
         if cl.func.kind() == ast.ASTKind.Attribute:
             # Take the segment left of the variant name as the enum class name
@@ -474,6 +474,24 @@ novirtual class ExprGenBase:
         """Are a and b the same aggregate type; 1=yes / 0=no."""
         if a is None or b is None: return 0
         return self.Gen.AssignGen._stg_ty_equal(pool, a, b)
+    # _agg_value_slot_ty - 值语义槽：源表达式的变量槽**自身**持有聚合物（`x: Foo`，Spec.PtrLevel == 0）。
+    # 形参按「聚合一律按指针传」的 ABI 到达，但它在被调者里同样物化在自己的槽中，读槽即值拷贝；
+    # 真·指针值（`p: Foo*`，Spec.PtrLevel >= 1）返回 None，仍必须显式解引用（c.deref(p) / *p）。
+    # 返回该聚合类型；不适用时 None。
+    def _agg_value_slot_ty(self, node: ast.AST*, val: mlirlite.Value*, trans: HT.Translator*) -> mlirlite.LLVMType*:
+        """Aggregate type when the source is a variable slot holding the aggregate by value; else None."""
+        n: ast.AST* = self._value_node_of(node)
+        if n is None or n.kind() != ast.ASTKind.Name: return None
+        nm: str = (ast.Name*(n)).id
+        if nm is None or trans is None: return None
+        ve: GenTypes.VarEntry* = self.Gen.VarGen.lookup_var_entry(trans.SymTab, nm)
+        if ve is None or ve.Alloca is None or ve.Spec is None: return None
+        # 必须是槽本身（若已被加载成指针值，说明源本来就是个指针，不豁免）。
+        if ve.Alloca is not val: return None
+        # 声明的就是 T*（PtrLevel>=1）：真指针，必须显式解引用。
+        if ve.Spec.PtrLevel != 0: return None
+        if self.is_ptr_type(ve.Alloca.Ty) == 0: return None
+        return ve.Alloca.Ty.Pointee
     # Type coercion: int sext/trunc, float fpext/fptrunc, int<->float si2fp/fp2si.
     def coerce_to_type(self, builder: mlirlite.IRBuilder*, val: mlirlite.Value*, target_ty: mlirlite.LLVMType*, node: ast.AST* = None, trans: HT.Translator* = None) -> mlirlite.Value*:
         """Coerce val to target_ty: int sext/trunc, float fpext/fptrunc, int/float conversions."""
@@ -564,7 +582,7 @@ novirtual class ExprGenBase:
         if val_bits != 0 and target_fbits != 0: return mlirlite.build_si2fp(builder, val, target_ty)
         # float -> int
         if val_fbits != 0 and target_bits != 0: return mlirlite.build_fp2si(builder, val, target_ty)
-        # Aggregate value -> pointer: spill a temp to the entry block and pass its
+        # Aggregate value -> pointer: spill a temp to the entry block and pass its
         # address (TPV never passes aggregates by value).
         if self.is_ptr_type(val.Ty) == 0 and self.is_ptr_type(target_ty) != 0:
             vk_agg: int = val.Ty.kind()
@@ -596,6 +614,11 @@ novirtual class ExprGenBase:
                 # Rule 3: implicit ptr -> value for non-basic types (Foo* -> Foo) is
                 # forbidden, except "construction materialization" (see _ctor_call_agg_ty).
                 ctor_p2v: mlirlite.LLVMType* = self._ctor_call_agg_ty(node)
+                # 值语义槽豁免：源是变量槽自身持有聚合物（`x: Foo`；形参虽按「聚合按指针传」的
+                # ABI 到达，也物化在自己的槽中）时，读槽 = 值拷贝（`self.f = elem` 这类写法）。
+                slot_p2v: mlirlite.LLVMType* = self._agg_value_slot_ty(node, val, trans)
+                if self._same_agg_ty(builder.Pool, slot_p2v, target_ty) != 0:
+                    return mlirlite.build_load(builder, target_ty, val)
                 if self._same_agg_ty(builder.Pool, ctor_p2v, target_ty) == 0:
                     m_p2v: str = "implicit value/pointer conversion for non-basic types is forbidden (except construction materialization): a pointer type cannot be implicitly converted to a non-basic value (Foo* -> Foo); to dereference use c.deref(p) / *p explicitly, or cast explicitly"
                     p2v_txt: str = GenApi.escape_fstring_copy(f"; source type {self._type_text(builder.Pool, val.Ty)} -> target value type {self._type_text(builder.Pool, target_ty)}")
@@ -620,7 +643,7 @@ novirtual class ExprGenBase:
         if val is None or val.Ty is None: return 0
         return self.Gen.ExprGenOps.should_zext_widen(pool, val, None, node, trans)
 
-    # translate_ptr_arith: ptr +/- int via getelementptr (index scaled by pointee
+    # translate_ptr_arith: ptr +/- int via getelementptr (index scaled by pointee
     # size); array pointees ([N x ty]*) decay to element pointers first.
     def translate_ptr_arith(self, pool: memhub.MemBuddy*, builder: mlirlite.IRBuilder*, ptr_val: mlirlite.Value*, int_val: mlirlite.Value*, op: int) -> mlirlite.Value*:
         """Pointer arithmetic: ptr +/- int via GEP with the index scaled by element size."""