Destructuring default can't read an earlier binding; block function can't see a later const; panic on static #field + private accessor pair #1002

1. A destructuring default that reads an earlier binding of the same pattern throws inside any function or block.

function f() { const { a, b = a } = { a: 1 }; return b; }
print(f());

nova eval t1.js throws Uncaught exception: ReferenceError: can't access lexical declaration 'a' before initialization (expected 1). The same happens for let, var, [a, b = a], and parameters (({ width, height = width }) => ...), because IdentifierReference::compile treats any reference whose AST ancestor is the enclosing VariableDeclarator or FormalParameter as a self-referential TDZ access (bytecode_compiler.rs:879-885).

2. A function declared in a block can't see a const or let declared later in that block.

{ function h() { return c; } const c = 2; print(h()); }

nova eval t2.js throws Uncaught exception: ReferenceError: Cannot access undeclared variable 'c'. (expected 2). In block_declaration_instantiation.rs:144-160, FunctionDeclaration is compiled during handle_block_lexically_scoped_declaration before later lexical declarations in the same block have called enter_lexical_scope().

3. Panic on class definition with a static private field and an instance private getter/setter pair.

class A { static #a = 1; get #b() {} set #b(v) {} }

nova eval t3.js panics:

thread 'main' panicked at nova_vm/src/ecmascript/execution/environments/private_environment.rs:279:13:
Attempted to get PrivateName outside the Private Environment's range

instance_private_method_count is incremented for both get #b and set #b (class_definition_evaluation.rs:249), while private_name_lookup_map deduplicates the pair to one PrivateName, so the static private field offset (instance_private_field_count + instance_private_method_count + private_identifier) exceeds private_env.names.len().

4. pop(), shift(), and splice() on a non-extensible array throw TypeError.

const a = Object.preventExtensions([1, 2]);
print(a.pop());

nova eval t4.js throws Uncaught exception: TypeError: Could not set property. (expected 2). Array::internal_set_extensible sets elems.len_writable = value (array.rs:320), marking length as non-writable when extensions are prevented even though Object.preventExtensions leaves length writable.

Version: main (591bf7ba0d, 2026-11-07), cargo build --release -p nova_cli.

Credit: https://ucsbplse.github.io/