issue17318.go

     1  // errorcheck -0 -N -m -l
     2  
     3  // Copyright 2016 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  // The escape analyzer needs to run till its root set settles
     8  // (this is not that often, it turns out).
     9  // This test is likely to become stale because the leak depends
    10  // on a spurious-escape bug -- return an interface as a named
    11  // output parameter appears to cause the called closure to escape,
    12  // where returning it as a regular type does not.
    13  
    14  package main
    15  
    16  import (
    17  	"fmt"
    18  )
    19  
    20  type closure func(i, j int) ent
    21  
    22  type ent int
    23  
    24  func (e ent) String() string {
    25  	return fmt.Sprintf("%d", int(e)) // ERROR "... argument does not escape$" "int\(e\) escapes to heap$"
    26  }
    27  
    28  //go:noinline
    29  func foo(ops closure, j int) (err fmt.Stringer) { // ERROR "ops does not escape"
    30  	enqueue := func(i int) fmt.Stringer { // ERROR "func literal does not escape"
    31  		return ops(i, j) // ERROR "ops\(i, j\) escapes to heap$"
    32  	}
    33  	err = enqueue(4)
    34  	if err != nil {
    35  		return err
    36  	}
    37  	return // return result of enqueue, a fmt.Stringer
    38  }
    39  
    40  func main() {
    41  	// 3 identical functions, to get different escape behavior.
    42  	f := func(i, j int) ent { // ERROR "func literal does not escape"
    43  		return ent(i + j)
    44  	}
    45  	i := foo(f, 3).(ent)
    46  	fmt.Printf("foo(f,3)=%d\n", int(i)) // ERROR "int\(i\) escapes to heap$" "... argument does not escape$"
    47  }
    48
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