feat: user type registry and enumerated types (CIE 4.1/4.2)

- TypeSystem: TypeKinds Enum/Record/Pointer with per-kind payloads and
  checked accessors; two-pass registration (names first, then definitions
  in source order) so pointer TYPEs may forward-reference; enum-constant
  table owned by TypeSystem so constants stay visible inside function
  bodies across the Symbols save/clear/restore. Dead surface removed
  (Custom kind, Printable/Builtin/ReferenceLike, ElementSize, hasType,
  CodeGen::getNamedValue/getLLVMType).
- Enums are i64 with 0-based ordinals (constexpr kEnumOrdinalBase); all
  type identity is by NAME. New emitCoercedExpr is the single admission
  gate, replacing raw coercion at assignments, array stores, BYVAL args,
  RETURN, IF/WHILE/REPEAT/FOR operands, file operands and builtin args;
  coerceValueToType now hard-errors if a user-kind target reaches it.
- Binary ops with user-kind operands are intercepted ahead of
  ArithmeticHandler ('&'-intercept precedent): same-enum comparisons,
  enum +/- INTEGER (with a runtime range check, [Fatal] on overflow, the
  only site that can manufacture an invalid ordinal), same-name pointer
  =/<>; everything else is a compile error naming the operator.
- OUTPUT is an exhaustive switch over TypeKind (enum prints its ordinal;
  record/pointer are compile errors, also covering whole-array OUTPUT);
  INPUT's silent %lld fallback for unknown kinds is now an explicit error.
- Enum value names are globally reserved: collisions with DECLARE,
  array names, parameters and function names are compile errors.
- RuntimeCheck: emitEnumRangeCheck + emitNullDerefCheck (used by the
  pointer phase) following the emitIndexCheck recipe.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

1 files changed, 11 insertions, 3 deletions

diff --git a/include/cps/CodeGen.h b/include/cps/CodeGen.h
index 2451cbd..713d02b 100644
--- a/include/cps/CodeGen.h
+++ b/include/cps/CodeGen.h
@@ -64,6 +64,10 @@ class CodeGen {
     bool isWholeArrayVar(ExprAST *Expr) const;
     const TypeInfo *getExprTypeInfo(ExprAST *Expr) const;
     llvm::Value *coerceValueToType(llvm::Value *Val, const TypeInfo *TargetInfo);
+
+    // TYPE-system helpers (Designator.cc).
+    void runTypePrePass(const std::vector<std::unique_ptr<StmtAST>> &Statements);
+    llvm::Value *emitUserKindBinaryOp(BinaryExprAST *Bin, const TypeInfo *LT, const TypeInfo *RT);
     bool marshalCallArgs(const std::string &Callee,
                          const std::vector<std::unique_ptr<ExprAST>> &ArgExprs,
                          std::vector<llvm::Value*> &Out);
@@ -90,10 +94,14 @@ public:
     // STRING slots zero-init to null; normalize null to "" at load/print sites.
     llvm::Value *emitStringNullGuard(llvm::Value *StrVal);
 
+    // Name-level admission gate for Enum/Record/Pointer plus the existing
+    // representation coercion for builtin targets. The ONLY door through
+    // which assignments, BYVAL args, RETURN values and file/builtin operands
+    // may produce a typed value. (Designator.cc)
+    llvm::Value *emitCoercedExpr(ExprAST *E, const TypeInfo *TargetInfo);
+
     const TypeInfo *resolveType(const std::string &TypeName) const;
-    llvm::Type *getLLVMType(const std::string &TypeName) const;
-    llvm::Value *getNamedValue(const std::string &Name) const;
-    
+
     friend class ArrayHandler;
 };