diff --git a/src/cmd/go/internal/modload/testgo.go b/src/cmd/go/internal/modload/testgo.go
index 663b24a68d..6b34f5be39 100644
--- a/src/cmd/go/internal/modload/testgo.go
+++ b/src/cmd/go/internal/modload/testgo.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//+build testgo
+// +build testgo
 
 package modload
 
diff --git a/src/cmd/go/internal/renameio/renameio_test.go b/src/cmd/go/internal/renameio/renameio_test.go
index 81dba6d545..ace6e493cb 100644
--- a/src/cmd/go/internal/renameio/renameio_test.go
+++ b/src/cmd/go/internal/renameio/renameio_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//+build !plan9
+// +build !plan9
 
 package renameio
 
diff --git a/src/cmd/go/internal/renameio/umask_test.go b/src/cmd/go/internal/renameio/umask_test.go
index 1a471c9e4e..031fe46e09 100644
--- a/src/cmd/go/internal/renameio/umask_test.go
+++ b/src/cmd/go/internal/renameio/umask_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//+build !nacl,!plan9,!windows,!js
+// +build !nacl,!plan9,!windows,!js
 
 package renameio
 
diff --git a/src/cmd/go/internal/robustio/robustio_other.go b/src/cmd/go/internal/robustio/robustio_other.go
index 91ca56cb82..56e6ad6d9c 100644
--- a/src/cmd/go/internal/robustio/robustio_other.go
+++ b/src/cmd/go/internal/robustio/robustio_other.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//+build !windows
+// +build !windows
 
 package robustio
 
diff --git a/src/cmd/go/internal/web/url_other.go b/src/cmd/go/internal/web/url_other.go
index bd243e591a..2641ee62bf 100644
--- a/src/cmd/go/internal/web/url_other.go
+++ b/src/cmd/go/internal/web/url_other.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//+build !windows
+// +build !windows
 
 package web
 
diff --git a/src/cmd/go/internal/web/url_other_test.go b/src/cmd/go/internal/web/url_other_test.go
index b4a74d94b9..aa5663355e 100644
--- a/src/cmd/go/internal/web/url_other_test.go
+++ b/src/cmd/go/internal/web/url_other_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//+build !windows
+// +build !windows
 
 package web
 
diff --git a/src/cmd/go/testdata/script/test_compile_binary.txt b/src/cmd/go/testdata/script/test_compile_binary.txt
index 6562f2453f..63bb8ec3e7 100644
--- a/src/cmd/go/testdata/script/test_compile_binary.txt
+++ b/src/cmd/go/testdata/script/test_compile_binary.txt
@@ -4,5 +4,5 @@ env GO111MODULE=off
 stderr 'build comment'
 
 -- compile_binary/foo_test.go --
-//+build foo
+// +build foo
 package foo
diff --git a/src/runtime/semasleep_test.go b/src/runtime/semasleep_test.go
index f5b4a50697..3eb7c6a6d1 100644
--- a/src/runtime/semasleep_test.go
+++ b/src/runtime/semasleep_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//+build !nacl,!plan9,!windows,!js
+// +build !nacl,!plan9,!windows,!js
 
 package runtime_test