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![Robert Griesemer](/assets/img/avatar_default.png)
- Use the correct predicate in Checker.implements: for interfaces we cannot use the API Comparable because it always returns true for all non-type parameter interface types: Comparable simply answers if == and != is permitted, and it's always been permitted for interfaces. Instead we must use Interface.IsComparable which looks at the type set of an interface. - When comparing interfaces for identity, we must also consider the whether the type sets have the comparable bit set. With this change, `any` doesn't implement `comparable` anymore. This only matters for generic functions and types, and the API functions. It does mean that for now (until we allow type-constrained interfaces for general non-constraint use, at some point in the future) a type parameter that needs to be comparable cannot be instantiated with an interface anymore. For #50646. Change-Id: I7e7f711bdcf94461f330c90509211ec0c2cf3633 Reviewed-on: https://go-review.googlesource.com/c/go/+/381254 Trust: Robert Griesemer <gri@golang.org> Reviewed-by: Robert Findley <rfindley@google.com>
20 lines
351 B
Go
20 lines
351 B
Go
// run -gcflags=-G=3
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// Copyright 2021 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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import "fmt"
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func main() {
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IsZero[int](0)
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}
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func IsZero[T comparable](val T) bool {
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var zero T
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fmt.Printf("%v:%v\n", zero, val)
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return val != zero
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}
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