[SuperPiIot]

Summary

Implements Structured Task Scopes (scope { ... }) and Affine JoinHandle[T] Lifetime Checking (HYB-E3501, HYB-E3502, HYB-E3503) natively in the Rust compiler crates (hy-syntax and hy-check), addressing #1669 and the maintainer design note in #1669 (comment).

Architectural Changes

1. Single Lexical Containment Authority (compiler/crates/hy-check/src/walk.rs):
   • Extended FlatInfo<'a> with pub scope_end: HashMap<usize, usize> alongside managed_end and loop_end, providing FlatInfo::in_scope(idx) and FlatInfo::enclosing_scope(idx) as the single authority for lexical scope { ... } containment.
2. Contextual scope Blocks & Handle-Producing task Expressions (compiler/crates/hy-syntax/src/parser.rs):
   • Parsed contextual scope { ... } and scope <ident> { ... } in statement position without reserving scope as a lexer keyword (preserving scope := 1 and scope(x) compatibility).
   • Parsed expression-position task <call> (e.g., h := task worker(i)) into the internal __hy_task_spawn call representation while keeping statement-level task worker() intact.
3. Structured Task Scope & Affine Handle Checker (compiler/crates/hy-check/src/task_scope.rs):
   • HYB-E3501 (Unjoined Task Escape): Rejects bare task or _ := task ... inside scope, handles unjoined at normal or early scope exit (return, break, continue), handle overwrites before consumption, partial consumption across non-diverging if/match/select branches, and handle escapes via return/channel-send/call arguments/assignments.
   • HYB-E3502 (Affine JoinHandle Double Consumption / Use-After-Consume): Enforces single consumption across join(h), cancel(h), drain(h), and method syntax (h.join(), h.cancel(), h.drain()), including branch-sensitive consumption and defer.
   • HYB-E3503 (Foreign Callback Spawn): Rejects spawning a task inside a closure literal passed to a foreign/selector call unless wrapped in an inner scope { ... } or managed { ... }.
   • managed { ... } Escape Hatch: Queries FlatInfo::in_managed(idx) to downgrade HYB-E3501 and HYB-E3503 inside managed blocks while keeping HYB-E3502 (double-consume) enforced.
4. Sandbox PATH Fix (tests/test_install_runtime.py):
   • Added "mv" to required_tools in InstallRuntimeTests._make_fake_curl_env so install.sh atomic staging succeeds in isolated test PATH environments.

Verification

• cargo test -p hy-check --test task_scope_test (all positive and negative HYB-E3501 / HYB-E3502 / HYB-E3503 cases pass)
• cargo test -p hy-syntax (all 135+ lexer/parser/corpus tests pass)
• python3 -m unittest tests.test_install_runtime (all 14 runtime installer tests pass)
• python3 tools/shepherd.py test-check & python3 tools/shepherd.py probe pass cleanly

Fixes #1669

Settlement Coordinates

• Network: Base Mainnet (Chain ID 8453)
• Asset: USDC
• Wallet: 0xf084cF0076F91AA48C2370F427C399dAA8C1f07F