methodsets.go

     1  // Copyright 2013 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package methodsets
     6  
     7  type T0 struct {}
     8  
     9  func (T0) v0() {}
    10  func (*T0) p0() {}
    11  
    12  type T1 struct {} // like T0 with different method names
    13  
    14  func (T1) v1() {}
    15  func (*T1) p1() {}
    16  
    17  type T2 interface {
    18  	v2()
    19  	p2()
    20  }
    21  
    22  type T3 struct {
    23  	T0
    24  	*T1
    25  	T2
    26  }
    27  
    28  // Method expressions
    29  func _() {
    30  	var (
    31  		_ func(T0) = T0.v0
    32  		_ = T0.p0 /* ERROR "invalid method expression T0.p0 (needs pointer receiver (*T0).p0)" */
    33  
    34  		_ func (*T0) = (*T0).v0
    35  		_ func (*T0) = (*T0).p0
    36  
    37  		// T1 is like T0
    38  
    39  		_ func(T2) = T2.v2
    40  		_ func(T2) = T2.p2
    41  
    42  		_ func(T3) = T3.v0
    43  		_ func(T3) = T3.p0 /* ERROR "invalid method expression T3.p0 (needs pointer receiver (*T3).p0)" */
    44  		_ func(T3) = T3.v1
    45  		_ func(T3) = T3.p1
    46  		_ func(T3) = T3.v2
    47  		_ func(T3) = T3.p2
    48  
    49  		_ func(*T3) = (*T3).v0
    50  		_ func(*T3) = (*T3).p0
    51  		_ func(*T3) = (*T3).v1
    52  		_ func(*T3) = (*T3).p1
    53  		_ func(*T3) = (*T3).v2
    54  		_ func(*T3) = (*T3).p2
    55  	)
    56  }
    57  
    58  // Method values with addressable receivers
    59  func _() {
    60  	var (
    61  		v0 T0
    62  		_ func() = v0.v0
    63  		_ func() = v0.p0
    64  	)
    65  
    66  	var (
    67  		p0 *T0
    68  		_ func() = p0.v0
    69  		_ func() = p0.p0
    70  	)
    71  
    72  	// T1 is like T0
    73  
    74  	var (
    75  		v2 T2
    76  		_ func() = v2.v2
    77  		_ func() = v2.p2
    78  	)
    79  
    80  	var (
    81  		v4 T3
    82  		_ func() = v4.v0
    83  		_ func() = v4.p0
    84  		_ func() = v4.v1
    85  		_ func() = v4.p1
    86  		_ func() = v4.v2
    87  		_ func() = v4.p2
    88  	)
    89  
    90  	var (
    91  		p4 *T3
    92  		_ func() = p4.v0
    93  		_ func() = p4.p0
    94  		_ func() = p4.v1
    95  		_ func() = p4.p1
    96  		_ func() = p4.v2
    97  		_ func() = p4.p2
    98  	)
    99  }
   100  
   101  // Method calls with addressable receivers
   102  func _() {
   103  	var v0 T0
   104  	v0.v0()
   105  	v0.p0()
   106  
   107  	var p0 *T0
   108  	p0.v0()
   109  	p0.p0()
   110  
   111  	// T1 is like T0
   112  
   113  	var v2 T2
   114  	v2.v2()
   115  	v2.p2()
   116  
   117  	var v4 T3
   118  	v4.v0()
   119  	v4.p0()
   120  	v4.v1()
   121  	v4.p1()
   122  	v4.v2()
   123  	v4.p2()
   124  
   125  	var p4 *T3
   126  	p4.v0()
   127  	p4.p0()
   128  	p4.v1()
   129  	p4.p1()
   130  	p4.v2()
   131  	p4.p2()
   132  }
   133  
   134  // Method values with value receivers
   135  func _() {
   136  	var (
   137  		_ func() = T0{}.v0
   138  		_ func() = T0{}.p0 /* ERROR "cannot call pointer method p0 on T0" */
   139  
   140  		_ func() = (&T0{}).v0
   141  		_ func() = (&T0{}).p0
   142  
   143  		// T1 is like T0
   144  
   145  		// no values for T2
   146  
   147  		_ func() = T3{}.v0
   148  		_ func() = T3{}.p0 /* ERROR "cannot call pointer method p0 on T3" */
   149  		_ func() = T3{}.v1
   150  		_ func() = T3{}.p1
   151  		_ func() = T3{}.v2
   152  		_ func() = T3{}.p2
   153  
   154  		_ func() = (&T3{}).v0
   155  		_ func() = (&T3{}).p0
   156  		_ func() = (&T3{}).v1
   157  		_ func() = (&T3{}).p1
   158  		_ func() = (&T3{}).v2
   159  		_ func() = (&T3{}).p2
   160  	)
   161  }
   162  
   163  // Method calls with value receivers
   164  func _() {
   165  	T0{}.v0()
   166  	T0{}.p0 /* ERROR "cannot call pointer method p0 on T0" */ ()
   167  
   168  	(&T0{}).v0()
   169  	(&T0{}).p0()
   170  
   171  	// T1 is like T0
   172  
   173  	// no values for T2
   174  
   175  	T3{}.v0()
   176  	T3{}.p0 /* ERROR "cannot call pointer method p0 on T3" */ ()
   177  	T3{}.v1()
   178  	T3{}.p1()
   179  	T3{}.v2()
   180  	T3{}.p2()
   181  
   182  	(&T3{}).v0()
   183  	(&T3{}).p0()
   184  	(&T3{}).v1()
   185  	(&T3{}).p1()
   186  	(&T3{}).v2()
   187  	(&T3{}).p2()
   188  }
   189  
   190  // *T has no methods if T is an interface type
   191  func issue5918() {
   192  	var (
   193  		err error
   194  		_ = err.Error()
   195  		_ func() string = err.Error
   196  		_ func(error) string = error.Error
   197  
   198  		perr = &err
   199  		_ = perr.Error /* ERROR "type *error is pointer to interface, not interface" */ ()
   200  		_ func() string = perr.Error /* ERROR "type *error is pointer to interface, not interface" */
   201  		_ func(*error) string = (*error).Error /* ERROR "type *error is pointer to interface, not interface" */
   202  	)
   203  
   204  	type T *interface{ m() int }
   205  	var (
   206  		x T
   207  		_ = (*x).m()
   208  		_ = (*x).m
   209  
   210  		_ = x.m /* ERROR "type T is pointer to interface, not interface" */ ()
   211  		_ = x.m /* ERROR "type T is pointer to interface, not interface" */
   212  		_ = T.m /* ERROR "type T is pointer to interface, not interface" */
   213  	)
   214  }
   215
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