rustc-dev-guide/src/rustc-driver/interacting-with-the-ast.md

Example: Type checking through rustc_driver

rustc_driver allows you to interact with Rust code at various stages of compilation.

Getting the type of an expression

To get the type of an expression, use the after_analysis callback to get a TyCtxt.

{{#include ../../examples/rustc-driver-interacting-with-the-ast.rs}}