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distinctBase now is identity instead of error for non distinct types (#16891)

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Timothee Cour 2021-02-01 04:10:52 -08:00 • committed by GitHub
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4 changed files with 14 additions and 16 deletions
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14
lib/pure/typetraits.nim
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@ -86,26 +86,26 @@ proc isNamedTuple*(T: typedesc): bool {.magic: "TypeTrait".} =
doAssert isNamedTuple(tuple[name: string, age: int])
proc distinctBase*(T: typedesc): typedesc {.magic: "TypeTrait".} =
## Returns the base type for distinct types. This works only
## for distinct types and produces a compile time error otherwise.
## Returns the base type for distinct types, or the type itself otherwise.
##
## **See also:**
## * `distinctBase template <#distinctBase.t,T>`_
runnableExamples:
type MyInt = distinct int
doAssert distinctBase(MyInt) is int
doAssert not compiles(distinctBase(int))
doAssert distinctBase(int) is int
since (1, 1):
template distinctBase*[T](a: T): untyped =
## Overload of `distinctBase <#distinctBase,typedesc>`_ for values.
runnableExamples:
type MyInt = distinct int
doAssert 12.MyInt.distinctBase == 12
distinctBase(type(a))(a)
doAssert 12.distinctBase == 12
when T is distinct:
distinctBase(type(a))(a)
else: # avoids hint ConvFromXtoItselfNotNeeded
a
proc tupleLen*(T: typedesc[tuple]): int {.magic: "TypeTrait".} =
## Returns the number of elements of the tuple type `T`.