fix(compiler): preserve optional-chain continuations and receivers

[metaphorics]

Change

Route nullish exits past an entire optional chain, including computed keys, following calls, non-null assertions, and delete operations. Preserve the receiver through parenthesized optional method calls. Replace separate member/call lowering paths with one chain-reference mechanism.

Evidence

The committed strict TypeScript fixture was compiled by TypeScript 7.0.2 and executed by Node 24.18.0. Before the fix, null chains performed four forbidden side effects and a grouped method lost its receiver. Both JIT and AOT now match the reference output.

• All 142 lowering tests pass, including const-enum rejection guards.
• Full bamts-cli crate passes, including all 51 CLI integration tests.
• Compiler/CLI all-target clippy with warnings denied passes.
• Formatting and diff whitespace checks pass.

Stack

Depends on #219; follows merged #217. Refs #157.

Known residuals

The checker can still report BAMTS-C064 for a valid optional-chain indexed access. This PR fixes execution semantics, not full checker compatibility or formal release admission.

Post-Deploy Monitoring & Validation

Owner: repository maintainers. Run the committed optional-chain regression and full CLI suite on the first CI run after integration. Healthy: exact oracle output and no existing regressions. Any output mismatch or const-enum regression blocks integration and triggers reverting this commit.

[coderabbitai]

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📥 Commits

Reviewing files that changed from the base of the PR and between 787d663 and 035db4e.

📒 Files selected for processing (3)

• crates/bamts-cli/tests/cli.rs
• crates/bamts-cli/tests/fixtures/optional-chain-continuations.ts
• crates/bamts-compiler/src/lower.rs

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[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-20T08:03:10.841169Z	035db4e	New commits

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[amazon-q-developer]

This PR adds proper parenthesization handling for optional chain expressions when followed by call expressions. The change correctly extends the needs_parens logic to include CallExpression as a parent case, ensuring proper formatting precedence. The implementation is well-tested with comprehensive fixtures covering various optional chaining scenarios.

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