Crate rustc_typeck [−] [src]

Unstable (rustc_private)

typeck.rs, an introduction

The type checker is responsible for:

Determining the type of each expression
Resolving methods and traits
Guaranteeing that most type rules are met ("most?", you say, "why most?" Well, dear reader, read on)

The main entry point is check_crate(). Type checking operates in several major phases:

The collect phase first passes over all items and determines their type, without examining their "innards".
Variance inference then runs to compute the variance of each parameter
Coherence checks for overlapping or orphaned impls
Finally, the check phase then checks function bodies and so forth. Within the check phase, we check each function body one at a time (bodies of function expressions are checked as part of the containing function). Inference is used to supply types wherever they are unknown. The actual checking of a function itself has several phases (check, regionck, writeback), as discussed in the documentation for the check module.

The type checker is defined into various submodules which are documented independently:

astconv: converts the AST representation of types into the ty representation
collect: computes the types of each top-level item and enters them into the cx.tcache table for later use
coherence: enforces coherence rules, builds some tables
variance: variance inference
check: walks over function bodies and type checks them, inferring types for local variables, type parameters, etc as necessary.
infer: finds the types to use for each type variable such that all subtyping and assignment constraints are met. In essence, the check module specifies the constraints, and the infer module solves them.

Note

This API is completely unstable and subject to change.

check	[Unstable]
check_unused	[Unstable]
coherence	[Unstable]
collect	[Unstable]
dep_graph	[Unstable]
diagnostics	[Unstable]
hir	[Unstable]
lint	[Unstable] Lints, aka compiler warnings.
middle	[Unstable]
session	[Unstable]
util	[Unstable]
variance	[Unstable] Module for inferring the variance of type and lifetime parameters. See README.md for details.

CrateCtxt	[Unstable]
TypeAndSubsts	[Unstable]

[Unstable]

check_crate	[Unstable]
emit_type_err	[Unstable]