fix: close type-safety holes found by adversarial review; update docs

Review findings (all reproduced, then fixed and re-verified):
- '^x' leaked as a raw address into any builtin context (s <- ^x printed
  the variable's bytes as a C string; NOT ^x, '&', and ^x = ^x compiled).
  Address-of is now rejected everywhere except a pointer-typed target.
- A whole-array variable passed the nominal gate as a value of its
  ELEMENT type (s <- arrayOfSeason stored the raw data pointer; = on it
  emitted invalid IR). Whole arrays are now rejected as operands and as
  coercion sources; array parameters are unaffected.
- Enum values smuggled into INTEGER through array subscripts and DECLARE
  bounds (a[Autumn], ARRAY[Spring:Winter]); both now go through
  emitCoercedExpr like every other INTEGER context.
- An array DECLAREd inside an IF/WHILE/REPEAT/FOR body and used after the
  block was a wild-pointer write (constant bounds) or a verifier dump
  (runtime bounds). Arrays are now block-scoped: control-flow bodies
  snapshot and restore the ArrayTable, so escape is a clean compile error.
- Duplicate parameter names silently shadowed (BYREF write-back defeated);
  now a parse error. Trailing comma in parameter lists accepted; now a
  parse error consistent with every other list.
- A variable/array/parameter/function could reuse a TYPE name; reserved.
- RETURN with a value inside a PROCEDURE was silently discarded (control
  did not return); now an error, as is a bare RETURN in a FUNCTION.
- INPUT r.f mis-parsed into a three-error cascade; now one clear error.
- Assigning to an enum constant now says so instead of 'Unknown variable'.

Docs: ARCH/CONVENTIONS/EXTENDING/SUBSYSTEMS/PITFALLS rewritten for the
TYPE system (ABI additions, nominal-typing invariants, admission-gate
doors, array-parameter ABI, new recipes, new sharp edges); README
features/TODO updated — random files are unblocked.

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

1 files changed, 5 insertions, 0 deletions

diff --git a/include/cps/ArrayHandler.h b/include/cps/ArrayHandler.h
index f555ee9..def174a 100644
--- a/include/cps/ArrayHandler.h
+++ b/include/cps/ArrayHandler.h
@@ -91,6 +91,11 @@ public:
     // the Symbols save/clear/restore discipline); returns the previous table.
     std::map<std::string, ArrayMetadata> exchangeTable(std::map<std::string, ArrayMetadata> NewTable);
 
+    // Copy for block-scoping: control-flow bodies snapshot before and restore
+    // after, so an array declared inside a branch cannot be referenced past it
+    // (its buffer setup and bound SSA values live inside the branch).
+    std::map<std::string, ArrayMetadata> snapshotTable() const { return ArrayTable; }
+
     // Callee side of an array parameter: rebuild metadata from the incoming
     // data pointer + per-dim bounds. MakeCopy (BYVAL) mallocs and memcpys the
     // whole buffer so callee writes stay invisible to the caller.