diff --git a/src/bytes/buffer.go b/src/bytes/buffer.go
index 14c5bc38d6..087cc0e427 100644
--- a/src/bytes/buffer.go
+++ b/src/bytes/buffer.go
@@ -12,13 +12,15 @@ import (
 	"unicode/utf8"
 )
 
+// smallBufferSize is an initial allocation minimal capacity.
+const smallBufferSize = 64
+
 // A Buffer is a variable-sized buffer of bytes with Read and Write methods.
 // The zero value for Buffer is an empty buffer ready to use.
 type Buffer struct {
-	buf       []byte   // contents are the bytes buf[off : len(buf)]
-	off       int      // read at &buf[off], write at &buf[len(buf)]
-	bootstrap [64]byte // memory to hold first slice; helps small buffers avoid allocation.
-	lastRead  readOp   // last read operation, so that Unread* can work correctly.
+	buf      []byte // contents are the bytes buf[off : len(buf)]
+	off      int    // read at &buf[off], write at &buf[len(buf)]
+	lastRead readOp // last read operation, so that Unread* can work correctly.
 
 	// FIXME: it would be advisable to align Buffer to cachelines to avoid false
 	// sharing.
@@ -125,9 +127,8 @@ func (b *Buffer) grow(n int) int {
 	if i, ok := b.tryGrowByReslice(n); ok {
 		return i
 	}
-	// Check if we can make use of bootstrap array.
-	if b.buf == nil && n <= len(b.bootstrap) {
-		b.buf = b.bootstrap[:n]
+	if b.buf == nil && n <= smallBufferSize {
+		b.buf = make([]byte, n, smallBufferSize)
 		return 0
 	}
 	c := cap(b.buf)
diff --git a/test/fixedbugs/issue7921.go b/test/fixedbugs/issue7921.go
new file mode 100644
index 0000000000..d32221a209
--- /dev/null
+++ b/test/fixedbugs/issue7921.go
@@ -0,0 +1,39 @@
+// errorcheck -0 -m
+
+// Copyright 2018 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.
+
+package foo
+
+import "bytes"
+
+// In order to get desired results, we need a combination of
+// both escape analysis and inlining.
+
+func bufferNotEscape() string {
+	// b itself does not escape, only its buf field will be
+	// copied during String() call, but object "handle" itself
+	// can be stack-allocated.
+	var b bytes.Buffer
+	b.WriteString("123") // ERROR "b does not escape"
+	b.Write([]byte{'4'}) // ERROR "b does not escape" "\[\]byte literal does not escape"
+	return b.String()    // ERROR "b does not escape" "inlining call" "string\(bytes\.b\.buf\[bytes.b.off:\]\) escapes to heap"
+}
+
+func bufferNoEscape2(xs []string) int { // ERROR "xs does not escape"
+	b := bytes.NewBuffer(make([]byte, 0, 64)) // ERROR "inlining call" "make\(\[\]byte, 0, 64\) does not escape" "&bytes.Buffer literal does not escape"
+	for _, x := range xs {
+		b.WriteString(x)
+	}
+	return b.Len() // ERROR "inlining call"
+}
+
+func bufferNoEscape3(xs []string) string { // ERROR "xs does not escape"
+	b := bytes.NewBuffer(make([]byte, 0, 64)) // ERROR "inlining call" "make\(\[\]byte, 0, 64\) does not escape" "&bytes.Buffer literal does not escape"
+	for _, x := range xs {
+		b.WriteString(x)
+		b.WriteByte(',')
+	}
+	return b.String() // ERROR "inlining call" "string\(bytes.b.buf\[bytes\.b\.off:\]\) escapes to heap"
+}