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Source file test/fixedbugs/issue12588.go

Documentation: test/fixedbugs

  // errorcheck -0 -m -l
  
  // Copyright 2015 The Go Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  // Tests escape analysis for range of arrays.
  // Compiles but need not run.  Inlining is disabled.
  
  package main
  
  type A struct {
  	b [3]uint64
  }
  
  type B struct {
  	b [3]*uint64
  }
  
  func f(a A) int {
  	for i, x := range &a.b { // ERROR "f &a.b does not escape"
  		if x != 0 {
  			return 64*i + int(x)
  		}
  	}
  	return 0
  }
  
  func g(a *A) int { // ERROR "g a does not escape"
  	for i, x := range &a.b { // ERROR "g &a.b does not escape"
  		if x != 0 {
  			return 64*i + int(x)
  		}
  	}
  	return 0
  }
  
  func h(a *B) *uint64 { // ERROR "leaking param: a to result ~r1 level=1"
  	for i, x := range &a.b { // ERROR "h &a.b does not escape"
  		if i == 0 {
  			return x
  		}
  	}
  	return nil
  }
  
  func h2(a *B) *uint64 { // ERROR "leaking param: a to result ~r1 level=1"
  	p := &a.b // ERROR "h2 &a.b does not escape"
  	for i, x := range p {
  		if i == 0 {
  			return x
  		}
  	}
  	return nil
  }
  
  // Seems like below should be level=1, not 0.
  func k(a B) *uint64 { // ERROR "leaking param: a to result ~r1 level=0"
  	for i, x := range &a.b { // ERROR "k &a.b does not escape"
  		if i == 0 {
  			return x
  		}
  	}
  	return nil
  }
  
  var sink *uint64
  
  func main() {
  	var a1, a2 A
  	var b1, b2, b3, b4 B
  	var x1, x2, x3, x4 uint64 // ERROR "moved to heap: x1" "moved to heap: x3"
  	b1.b[0] = &x1             // ERROR "&x1 escapes to heap"
  	b2.b[0] = &x2             // ERROR "main &x2 does not escape"
  	b3.b[0] = &x3             // ERROR "&x3 escapes to heap"
  	b4.b[0] = &x4             // ERROR "main &x4 does not escape"
  	f(a1)
  	g(&a2)         // ERROR "main &a2 does not escape"
  	sink = h(&b1)  // ERROR "main &b1 does not escape"
  	h(&b2)         // ERROR "main &b2 does not escape"
  	sink = h2(&b1) // ERROR "main &b1 does not escape"
  	h2(&b4)        // ERROR "main &b4 does not escape"
  	x1 = 17
  	println("*sink=", *sink) // Verify that sink addresses x1
  	x3 = 42
  	sink = k(b3)
  	println("*sink=", *sink) // Verify that sink addresses x3
  }
  

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