range.go

Documentation: internal/types/testdata/spec

     1  // -goexperiment=rangefunc
     2  
     3  // Copyright 2023 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  package p
     8  
     9  type MyInt int32
    10  type MyBool bool
    11  type MyString string
    12  type MyFunc1 func(func(int) bool)
    13  type MyFunc2 func(int) bool
    14  type MyFunc3 func(MyFunc2)
    15  
    16  type T struct{}
    17  
    18  func (*T) PM() {}
    19  func (T) M()   {}
    20  
    21  func f1()                             {}
    22  func f2(func())                       {}
    23  func f4(func(int) bool)               {}
    24  func f5(func(int, string) bool)       {}
    25  func f7(func(int) MyBool)             {}
    26  func f8(func(MyInt, MyString) MyBool) {}
    27  
    28  func test() {
    29  	// TODO: Would be nice to 'for range T.M' and 'for range (*T).PM' directly,
    30  	// but there is no gofmt-friendly way to write the error pattern in the right place.
    31  	m1 := T.M
    32  	for range m1 /* ERROR "cannot range over m1 (variable of type func(T)): func must be func(yield func(...) bool): argument is not func" */ {
    33  	}
    34  	m2 := (*T).PM
    35  	for range m2 /* ERROR "cannot range over m2 (variable of type func(*T)): func must be func(yield func(...) bool): argument is not func" */ {
    36  	}
    37  	for range f1 /* ERROR "cannot range over f1 (value of type func()): func must be func(yield func(...) bool): wrong argument count" */ {
    38  	}
    39  	for range f2 /* ERROR "cannot range over f2 (value of type func(func())): func must be func(yield func(...) bool): yield func does not return bool" */ {
    40  	}
    41  	for range f4 /* ERROR "range over f4 (value of type func(func(int) bool)) must have one iteration variable" */ {
    42  	}
    43  	for _ = range f4 {
    44  	}
    45  	for _, _ = range f5 {
    46  	}
    47  	for _ = range f7 {
    48  	}
    49  	for _, _ = range f8 {
    50  	}
    51  	for range 1 {
    52  	}
    53  	for range uint8(1) {
    54  	}
    55  	for range int64(1) {
    56  	}
    57  	for range MyInt(1) {
    58  	}
    59  	for range 'x' {
    60  	}
    61  	for range 1.0 /* ERROR "cannot range over 1.0 (untyped float constant 1)" */ {
    62  	}
    63  	for _ = range MyFunc1(nil) {
    64  	}
    65  	for _ = range MyFunc3(nil) {
    66  	}
    67  	for _ = range (func(MyFunc2))(nil) {
    68  	}
    69  
    70  	var i int
    71  	var s string
    72  	var mi MyInt
    73  	var ms MyString
    74  	for i := range f4 {
    75  		_ = i
    76  	}
    77  	for i = range f4 {
    78  		_ = i
    79  	}
    80  	for i, s := range f5 {
    81  		_, _ = i, s
    82  	}
    83  	for i, s = range f5 {
    84  		_, _ = i, s
    85  	}
    86  	for i, _ := range f5 {
    87  		_ = i
    88  	}
    89  	for i, _ = range f5 {
    90  		_ = i
    91  	}
    92  	for i := range f7 {
    93  		_ = i
    94  	}
    95  	for i = range f7 {
    96  		_ = i
    97  	}
    98  	for mi, _ := range f8 {
    99  		_ = mi
   100  	}
   101  	for mi, _ = range f8 {
   102  		_ = mi
   103  	}
   104  	for mi, ms := range f8 {
   105  		_, _ = mi, ms
   106  	}
   107  	for i /* ERROR "cannot use i (value of type MyInt) as int value in assignment" */, s /* ERROR "cannot use s (value of type MyString) as string value in assignment" */ = range f8 {
   108  		_, _ = mi, ms
   109  	}
   110  	for mi, ms := range f8 {
   111  		i, s = mi /* ERROR "cannot use mi (variable of type MyInt) as int value in assignment" */, ms /* ERROR "cannot use ms (variable of type MyString) as string value in assignment" */
   112  	}
   113  	for mi, ms = range f8 {
   114  		_, _ = mi, ms
   115  	}
   116  
   117  	for i := range 10 {
   118  		_ = i
   119  	}
   120  	for i = range 10 {
   121  		_ = i
   122  	}
   123  	for i, j /* ERROR "range over 10 (untyped int constant) permits only one iteration variable" */ := range 10 {
   124  		_, _ = i, j
   125  	}
   126  	for mi := range MyInt(10) {
   127  		_ = mi
   128  	}
   129  	for mi = range MyInt(10) {
   130  		_ = mi
   131  	}
   132  }
   133  
   134  func _[T int | string](x T) {
   135  	for range x /* ERROR "cannot range over x (variable of type T constrained by int | string): no core type" */ {
   136  	}
   137  }
   138  
   139  func _[T int | int64](x T) {
   140  	for range x /* ERROR "cannot range over x (variable of type T constrained by int | int64): no core type" */ {
   141  	}
   142  }
   143  
   144  func _[T ~int](x T) {
   145  	for range x { // ok
   146  	}
   147  }
   148  
   149  func _[T any](x func(func(T) bool)) {
   150  	for _ = range x { // ok
   151  	}
   152  }
   153  
   154  func _[T ~func(func(int) bool)](x T) {
   155  	for _ = range x { // ok
   156  	}
   157  }
   158
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