Examples

These walkthroughs follow small Rust programs through sage's implementation. They are ordered so that each chapter adds one major subsystem. Implementation extracts use mdbook-ezanchor to include named ANCHOR regions and link to their locations on GitHub; when the code changes, the book builds from the new source rather than retaining a stale copy.

1. Struct signature follows a parsed struct through generic-parameter lowering and field type checking.
2. Function body and field access adds function signatures, body inference, and generic field substitution.
3. Macro-generated struct shows how macro expansion feeds the same symbol and resolution pipeline.
4. A direct trait obligation follows a ground Widget: Marker goal from a call-site obligation to a canonical solver response.
5. A nested trait proof adds a generic impl, a where-clause body, concurrent alternatives, and a child proof frame.
6. An external trait method call follows self.db.clone() through prelude trait discovery, owned rustc metadata, a fixed-trait proof, and explicit receiver elaboration.
7. An oracle-checked method body shows how Sage and rustc independently project that completed body before an exact serialized comparison.

The architecture pages specify the system as a whole. These examples are the code-reading path into that specification.

The review-packet contract identifies the evidence that a mature walkthrough should collect. The module-expansion and oracle-checked-body examples are the initial complete packets; earlier examples remain useful narrower code tours.