test: add tests for escape analysis of closure arguments

10 false positives (var incorrectly escapes to heap) are marked with BAD.

Change-Id: I773b13a18ff55aaa499a2a28a979118422cc5322
Reviewed-on: https://go-review.googlesource.com/5293Reviewed-by: Keith Randall <khr@golang.org>

test/escape_closure.go

+// 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.
+
+// Test escape analysis for closure arguments.
+
+package escape
+
+var sink interface{}
+
+func ClosureCallArgs0() {
+	x := 0         // ERROR "moved to heap: x"
+	func(p *int) { // ERROR "p does not escape" "func literal does not escape"
+		*p = 1
+		// BAD: x should not escape to heap here
+	}(&x) // ERROR "&x escapes to heap"
+}
+
+func ClosureCallArgs1() {
+	x := 0 // ERROR "moved to heap: x"
+	for {
+		func(p *int) { // ERROR "p does not escape" "func literal does not escape"
+			*p = 1
+			// BAD: x should not escape to heap here
+		}(&x) // ERROR "&x escapes to heap"
+	}
+}
+
+func ClosureCallArgs2() {
+	for {
+		// BAD: x should not escape here
+		x := 0         // ERROR "moved to heap: x"
+		func(p *int) { // ERROR "p does not escape" "func literal does not escape"
+			*p = 1
+		}(&x) // ERROR "&x escapes to heap"
+	}
+}
+
+func ClosureCallArgs3() {
+	x := 0         // ERROR "moved to heap: x"
+	func(p *int) { // ERROR "leaking param: p" "func literal does not escape"
+		sink = p
+	}(&x) // ERROR "&x escapes to heap"
+}
+
+func ClosureCallArgs4() {
+	// BAD: x should not leak here
+	x := 0                  // ERROR "moved to heap: x"
+	_ = func(p *int) *int { // ERROR "leaking param: p to result ~r1" "func literal does not escape"
+		return p
+	}(&x) // ERROR "&x escapes to heap"
+}
+
+func ClosureCallArgs5() {
+	x := 0                     // ERROR "moved to heap: x"
+	sink = func(p *int) *int { // ERROR "leaking param: p to result ~r1" "func literal does not escape"
+		return p
+	}(&x) // ERROR "&x escapes to heap"
+}
+
+func ClosureCallArgs6() {
+	x := 0         // ERROR "moved to heap: x"
+	func(p *int) { // ERROR "moved to heap: p" "func literal does not escape"
+		sink = &p // ERROR "&p escapes to heap"
+	}(&x) // ERROR "&x escapes to heap"
+}
+
+func ClosureCallArgs7() {
+	var pp *int
+	for {
+		x := 0         // ERROR "moved to heap: x"
+		func(p *int) { // ERROR "leaking param: p" "func literal does not escape"
+			pp = p
+		}(&x) // ERROR "&x escapes to heap"
+	}
+	_ = pp
+}
+
+func ClosureCallArgs8() {
+	x := 0               // ERROR "moved to heap: x"
+	defer func(p *int) { // ERROR "p does not escape" "func literal does not escape"
+		*p = 1
+		// BAD: x should not escape to heap here
+	}(&x) // ERROR "&x escapes to heap"
+}
+
+func ClosureCallArgs9() {
+	// BAD: x should not leak
+	x := 0 // ERROR "moved to heap: x"
+	for {
+		defer func(p *int) { // ERROR "func literal escapes to heap" "p does not escape"
+			*p = 1
+		}(&x) // ERROR "&x escapes to heap"
+	}
+}
+
+func ClosureCallArgs10() {
+	for {
+		x := 0               // ERROR "moved to heap: x"
+		defer func(p *int) { // ERROR "func literal escapes to heap" "p does not escape"
+			*p = 1
+		}(&x) // ERROR "&x escapes to heap"
+	}
+}
+
+func ClosureCallArgs11() {
+	x := 0               // ERROR "moved to heap: x"
+	defer func(p *int) { // ERROR "leaking param: p" "func literal does not escape"
+		sink = p
+	}(&x) // ERROR "&x escapes to heap"
+}
+
+func ClosureCallArgs12() {
+	// BAD: x should not leak
+	x := 0                    // ERROR "moved to heap: x"
+	defer func(p *int) *int { // ERROR "leaking param: p to result ~r1" "func literal does not escape"
+		return p
+	}(&x) // ERROR "&x escapes to heap"
+}
+
+func ClosureCallArgs13() {
+	x := 0               // ERROR "moved to heap: x"
+	defer func(p *int) { // ERROR "moved to heap: p" "func literal does not escape"
+		sink = &p // ERROR "&p escapes to heap"
+	}(&x) // ERROR "&x escapes to heap"
+}
+
+func ClosureCallArgs14() {
+	x := 0 // ERROR "moved to heap: x"
+	// BAD: &x should not escape here
+	p := &x                  // ERROR "moved to heap: p" "&x escapes to heap"
+	_ = func(p **int) *int { // ERROR "leaking param p content to result ~r1" "func literal does not escape"
+		return *p
+		// BAD: p should not escape here
+	}(&p) // ERROR "&p escapes to heap"
+}
+
+func ClosureCallArgs15() {
+	x := 0                      // ERROR "moved to heap: x"
+	p := &x                     // ERROR "moved to heap: p" "&x escapes to heap"
+	sink = func(p **int) *int { // ERROR "leaking param p content to result ~r1" "func literal does not escape"
+		return *p
+		// BAD: p should not escape here
+	}(&p) // ERROR "&p escapes to heap"
+}