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Add non_exhaustive to reference. #609

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Merged
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Oct 26, 2019
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Add non_exhaustive to reference. #609

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363a64a
Add `non_exhaustive` to reference.
davidtwco May 12, 2019
909b4d1
Define inhabited/uninhabited in glossary.
davidtwco Oct 26, 2019
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14 changes: 14 additions & 0 deletions src/glossary.md
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Expand Up @@ -65,6 +65,12 @@ For example, `2 + (3 * 4)` is an expression that returns the value 14.
An [item] that is not a member of an [implementation], such as a *free
function* or a *free const*. Contrast to an [associated item].

### Inhabited

A type is inhabited if it has constructors and therefore can be instantiated. An inhabited type is
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Is your notion of "has constructors" intended to e.g. take visibility into account? That's the current definition of inhabitedness in the type system but not the abstract machine. You are describing this from the POV of the type system, right?

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Uh, yes..? I just borrowed the explanation from RFC 1216.

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I see. :) Well, this is good.

not "empty" in the sense that there can be values of the type. Opposite of
[Uninhabited](#uninhabited).

### Inherent implementation

An [implementation] that applies to a nominal type, not to a trait-type pair.
Expand Down Expand Up @@ -159,6 +165,13 @@ but is not limited to: process termination or corruption; improper, incorrect,
or unintended computation; or platform-specific results.
[More][undefined-behavior].

### Uninhabited

A type is uninhabited if it has no constructors and therefore can never be instantiated. An
uninhabited type is "empty" in the sense that there are no values of the type. The canonical
example of an uninhabited type is the [never type] `!`, or an enum with no variants
`enum Never { }`. Opposite of [Inhabited](#inhabited).

[alignment]: type-layout.md#size-and-alignment
[associated item]: #associated-item
[enums]: items/enumerations.md
Expand All @@ -168,6 +181,7 @@ or unintended computation; or platform-specific results.
[inherent implementation]: items/implementations.md#inherent-implementations
[item]: items.md
[method]: items/associated-items.md#methods
[never type]: types/never.md
[object safety]: items/traits.md#object-safety
[structs]: items/structs.md
[trait objects]: types/trait-object.md
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