diff --git a/src/cmd/go/go_test.go b/src/cmd/go/go_test.go
index 43660d75cc..b07b746054 100644
--- a/src/cmd/go/go_test.go
+++ b/src/cmd/go/go_test.go
@@ -1191,6 +1191,17 @@ func TestPackageMainTestImportsArchiveNotBinary(t *testing.T) {
 	tg.run("test", "main_test")
 }
 
+// Issue 12690
+func TestPackageNotStaleWithTrailingSlash(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	goroot := runtime.GOROOT()
+	tg.setenv("GOROOT", goroot+"/")
+	tg.wantNotStale("runtime", "with trailing slash in GOROOT, runtime listed as stale")
+	tg.wantNotStale("os", "with trailing slash in GOROOT, os listed as stale")
+	tg.wantNotStale("io", "with trailing slash in GOROOT, io listed as stale")
+}
+
 // With $GOBIN set, binaries get installed to $GOBIN.
 func TestInstallIntoGOBIN(t *testing.T) {
 	tg := testgo(t)
diff --git a/src/go/build/build.go b/src/go/build/build.go
index ce90f597fd..14a03fc0d4 100644
--- a/src/go/build/build.go
+++ b/src/go/build/build.go
@@ -289,7 +289,7 @@ func defaultContext() Context {
 
 	c.GOARCH = envOr("GOARCH", runtime.GOARCH)
 	c.GOOS = envOr("GOOS", runtime.GOOS)
-	c.GOROOT = runtime.GOROOT()
+	c.GOROOT = pathpkg.Clean(runtime.GOROOT())
 	c.GOPATH = envOr("GOPATH", "")
 	c.Compiler = runtime.Compiler