mirror of
https://github.com/golang/go
synced 2024-09-29 03:24:29 -06:00
16d6a5233a
Added a new absdiff2.go test case, which works fully without using a typeparam on the right-hand-side of a type declaration (which is disallowed). Fixed an issue that the test revealed, which is that we need to set g.curDecl properly for the "later" functions which are deferred until after all declarations are initially processed. Also, g.curDecl may be non-nil in typeDecl for local type declaration. So, we adjust the associate assertion, and save/restore g.curDecl appropriately. Fixes #50790 Change-Id: Ieed76a7ad0a83bccb99cbad4bf98a7bfafbcbbd3 Reviewed-on: https://go-review.googlesource.com/c/go/+/380594 Reviewed-by: Keith Randall <khr@golang.org> Trust: Dan Scales <danscales@google.com>
103 lines
2.8 KiB
Go
103 lines
2.8 KiB
Go
// run -gcflags=-G=3
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// Copyright 2022 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 (
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"fmt"
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"math"
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)
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type Numeric interface {
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~int | ~int8 | ~int16 | ~int32 | ~int64 |
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~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr |
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~float32 | ~float64 |
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~complex64 | ~complex128
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}
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// numericAbs matches a struct containing a numeric type that has an Abs method.
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type numericAbs[T Numeric] interface {
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~struct{ Value T }
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Abs() T
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}
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// AbsDifference computes the absolute value of the difference of
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// a and b, where the absolute value is determined by the Abs method.
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func absDifference[T Numeric, U numericAbs[T]](a, b U) T {
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d := a.Value - b.Value
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dt := U{Value: d}
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return dt.Abs()
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}
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// orderedNumeric matches numeric types that support the < operator.
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type orderedNumeric interface {
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~int | ~int8 | ~int16 | ~int32 | ~int64 |
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~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr |
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~float32 | ~float64
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}
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// Complex matches the two complex types, which do not have a < operator.
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type Complex interface {
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~complex64 | ~complex128
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}
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// orderedAbs is a helper type that defines an Abs method for
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// a struct containing an ordered numeric type.
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type orderedAbs[T orderedNumeric] struct {
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Value T
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}
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func (a orderedAbs[T]) Abs() T {
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if a.Value < 0 {
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return -a.Value
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}
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return a.Value
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}
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// complexAbs is a helper type that defines an Abs method for
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// a struct containing a complex type.
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type complexAbs[T Complex] struct {
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Value T
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}
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func (a complexAbs[T]) Abs() T {
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r := float64(real(a.Value))
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i := float64(imag(a.Value))
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d := math.Sqrt(r*r + i*i)
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return T(complex(d, 0))
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}
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// OrderedAbsDifference returns the absolute value of the difference
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// between a and b, where a and b are of an ordered type.
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func OrderedAbsDifference[T orderedNumeric](a, b T) T {
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return absDifference(orderedAbs[T]{a}, orderedAbs[T]{b})
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}
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// ComplexAbsDifference returns the absolute value of the difference
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// between a and b, where a and b are of a complex type.
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func ComplexAbsDifference[T Complex](a, b T) T {
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return absDifference(complexAbs[T]{a}, complexAbs[T]{b})
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}
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func main() {
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if got, want := OrderedAbsDifference(1.0, -2.0), 3.0; got != want {
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panic(fmt.Sprintf("got = %v, want = %v", got, want))
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}
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if got, want := OrderedAbsDifference(-1.0, 2.0), 3.0; got != want {
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panic(fmt.Sprintf("got = %v, want = %v", got, want))
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}
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if got, want := OrderedAbsDifference(-20, 15), 35; got != want {
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panic(fmt.Sprintf("got = %v, want = %v", got, want))
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}
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if got, want := ComplexAbsDifference(5.0+2.0i, 2.0-2.0i), 5+0i; got != want {
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panic(fmt.Sprintf("got = %v, want = %v", got, want))
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}
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if got, want := ComplexAbsDifference(2.0-2.0i, 5.0+2.0i), 5+0i; got != want {
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panic(fmt.Sprintf("got = %v, want = %v", got, want))
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}
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}
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