Extern import extraction contract - Design model

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This article documents design model for extern import extraction contract in the reference compiler.

What this covers

For newcomers, this page explains where the contract shows up in day-to-day compiler work and which code paths are most useful first reads.

Anchored code paths

• compiler/crates/beskid_abi/src/builtins.rs and symbols.rs define import-facing ABI names.
• compiler/crates/beskid_runtime/src/builtins/mod.rs provides runtime implementations for extracted imports.
• compiler/crates/beskid_e2e_tests/src/tests/runtime_cases.rs verifies extern calls end-to-end.

Practical notes

• Prefer tracing from CLI/test entry points into analysis/codegen crates before changing internals.
• Treat diagnostics and tests as part of the contract, not optional implementation details.
• If behavior changes, update this article and add/adjust tests in compiler/crates/beskid_tests or compiler/crates/beskid_e2e_tests.