Struct rustc::ty::_match::Match [] [src]

pub struct Match<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> { /* fields omitted */ }
🔬 This is a nightly-only experimental API. (rustc_private)

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A type "A" matches "B" if the fresh types in B could be substituted with values so as to make it equal to A. Matching is intended to be used only on freshened types, and it basically indicates if the non-freshened versions of A and B could have been unified.

It is only an approximation. If it yields false, unification would definitely fail, but a true result doesn't mean unification would succeed. This is because we don't track the "side-constraints" on type variables, nor do we track if the same freshened type appears more than once. To some extent these approximations could be fixed, given effort.

Like subtyping, matching is really a binary relation, so the only important thing about the result is Ok/Err. Also, matching never affects any type variables or unification state.

Methods

impl<'a, 'gcx, 'tcx> Match<'a, 'gcx, 'tcx>
[src]

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Trait Implementations

impl<'a, 'gcx, 'tcx> TypeRelation<'a, 'gcx, 'tcx> for Match<'a, 'gcx, 'tcx>
[src]

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Returns a static string we can use for printouts.

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Returns true if the value a is the "expected" type in the relation. Just affects error messages. Read more

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Switch variance for the purpose of relating a and b.

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Generic relation routine suitable for most anything.

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Relate the two substitutions for the given item. The default is to look up the variance for the item and proceed accordingly. Read more

Auto Trait Implementations

impl<'a, 'gcx, 'tcx> !Send for Match<'a, 'gcx, 'tcx>

impl<'a, 'gcx, 'tcx> !Sync for Match<'a, 'gcx, 'tcx>