22 lines
718 B
Racket
22 lines
718 B
Racket
#lang typed/racket
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;; The precise type for chars should be the char itself:
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(ann #\nul #\nul)
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(ann #\a #\a)
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(ann #\b '#\b)
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;; Up-casting as Char should still work:
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(ann #\nul Char)
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(ann #\a Char)
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(ann (ann #\b '#\b) Char)
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;; Check that the inferred type is still implicitly widened to Char by default,
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;; for backwards compatibility (previously, all chars had the type Char):
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;; * Check that when passed as a #:∀ type, the inferred type is Char
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(ann (let #:∀ (C) ([c : C #\a])
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(λ ([x : C]) x))
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(→ Char Char))
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;; * Check that loops which rely on the first iteration having the wider Char
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;; type still work:
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(let loop : Void ([c #\a])
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(if (equal? c #\a)
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(loop #\b)
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(void))) |