go source for verification 2026-05-22

test/escape_bloop.go

@@ -0,0 +1,64 @@
+// errorcheck -0 -m
+
+// Copyright 2026 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 b.Loop escape analysis behavior.
+
+package bloop
+
+import (
+	"testing"
+)
+
+// An example where mid-stack inlining allows stack allocation of a slice.
+// This is from the example in go.dev/issue/73137.
+
+func NewX(x int) []byte { // ERROR "can inline NewX"
+	out := make([]byte, 8) // ERROR "make\(\[\]byte, 8\) escapes to heap"
+	return use1(out)
+}
+
+//go:noinline
+func use1(out []byte) []byte { // ERROR "leaking param: out to result ~r0 level=0"
+	return out
+}
+
+//go:noinline
+func BenchmarkBloop(b *testing.B) { // ERROR "leaking param: b"
+	for b.Loop() { // ERROR "inlining call to testing.\(\*B\).Loop"
+		NewX(42) // ERROR "make\(\[\]byte, 8\) does not escape" "inlining call to NewX"
+	}
+}
+
+// A traditional b.N benchmark using a sink variable for comparison,
+// also from the example in go.dev/issue/73137.
+
+var sink byte
+
+//go:noinline
+func BenchmarkBN(b *testing.B) { // ERROR "b does not escape"
+	for i := 0; i < b.N; i++ {
+		out := NewX(42) // ERROR "make\(\[\]byte, 8\) does not escape" "inlining call to NewX"
+		sink = out[0]
+	}
+}
+
+// An example showing behavior of a simple function argument in the b.Loop body.
+
+//go:noinline
+func use2(x any) {} // ERROR "x does not escape"
+
+//go:noinline
+func BenchmarkBLoopFunctionArg(b *testing.B) { // ERROR "leaking param: b"
+	for b.Loop() { // ERROR "inlining call to testing.\(\*B\).Loop"
+		use2(42) // ERROR "42 does not escape"
+	}
+}
+
+// A similar call outside of b.Loop for comparison.
+
+func simpleFunctionArg() { // ERROR "can inline simpleFunctionArg"
+	use2(42) // ERROR "42 does not escape"
+}