diff --git a/src/cmd/go/internal/imports/build.go b/src/cmd/go/internal/imports/build.go
index ddf425b020..3718dbba3c 100644
--- a/src/cmd/go/internal/imports/build.go
+++ b/src/cmd/go/internal/imports/build.go
@@ -184,13 +184,13 @@ func MatchFile(name string, tags map[string]bool) bool {
 	}
 	n := len(l)
 	if n >= 2 && KnownOS[l[n-2]] && KnownArch[l[n-1]] {
-		return tags[l[n-2]] && tags[l[n-1]]
+		return matchTag(l[n-2], tags, true) && matchTag(l[n-1], tags, true)
 	}
 	if n >= 1 && KnownOS[l[n-1]] {
-		return tags[l[n-1]]
+		return matchTag(l[n-1], tags, true)
 	}
 	if n >= 1 && KnownArch[l[n-1]] {
-		return tags[l[n-1]]
+		return matchTag(l[n-1], tags, true)
 	}
 	return true
 }
diff --git a/src/cmd/go/internal/imports/scan_test.go b/src/cmd/go/internal/imports/scan_test.go
index 6a2ff62ba7..e424656cae 100644
--- a/src/cmd/go/internal/imports/scan_test.go
+++ b/src/cmd/go/internal/imports/scan_test.go
@@ -5,10 +5,13 @@
 package imports
 
 import (
+	"bytes"
 	"internal/testenv"
+	"io/ioutil"
+	"path"
 	"path/filepath"
-	"reflect"
 	"runtime"
+	"strings"
 	"testing"
 )
 
@@ -51,17 +54,41 @@ func TestScan(t *testing.T) {
 		t.Errorf("json missing test import net/http (%q)", testImports)
 	}
 }
-
-func TestScanStar(t *testing.T) {
+func TestScanDir(t *testing.T) {
 	testenv.MustHaveGoBuild(t)
 
-	imports, _, err := ScanDir("testdata/import1", map[string]bool{"*": true})
+	dirs, err := ioutil.ReadDir("testdata")
 	if err != nil {
 		t.Fatal(err)
 	}
+	for _, dir := range dirs {
+		if !dir.IsDir() || strings.HasPrefix(dir.Name(), ".") {
+			continue
+		}
+		t.Run(dir.Name(), func(t *testing.T) {
+			tagsData, err := ioutil.ReadFile(filepath.Join("testdata", dir.Name(), "tags.txt"))
+			if err != nil {
+				t.Fatalf("error reading tags: %v", err)
+			}
+			tags := make(map[string]bool)
+			for _, t := range strings.Fields(string(tagsData)) {
+				tags[t] = true
+			}
 
-	want := []string{"import1", "import2", "import3", "import4"}
-	if !reflect.DeepEqual(imports, want) {
-		t.Errorf("ScanDir testdata/import1:\nhave %v\nwant %v", imports, want)
+			wantData, err := ioutil.ReadFile(filepath.Join("testdata", dir.Name(), "want.txt"))
+			if err != nil {
+				t.Fatalf("error reading want: %v", err)
+			}
+			want := string(bytes.TrimSpace(wantData))
+
+			imports, _, err := ScanDir(path.Join("testdata", dir.Name()), tags)
+			if err != nil {
+				t.Fatal(err)
+			}
+			got := strings.Join(imports, "\n")
+			if got != want {
+				t.Errorf("ScanDir: got imports:\n%s\n\nwant:\n%s", got, want)
+			}
+		})
 	}
 }
diff --git a/src/cmd/go/internal/imports/testdata/android/a_android.go b/src/cmd/go/internal/imports/testdata/android/a_android.go
new file mode 100644
index 0000000000..2ed972eca5
--- /dev/null
+++ b/src/cmd/go/internal/imports/testdata/android/a_android.go
@@ -0,0 +1,3 @@
+package android
+
+import _ "a"
diff --git a/src/cmd/go/internal/imports/testdata/android/b_android_arm64.go b/src/cmd/go/internal/imports/testdata/android/b_android_arm64.go
new file mode 100644
index 0000000000..ee9c312b5d
--- /dev/null
+++ b/src/cmd/go/internal/imports/testdata/android/b_android_arm64.go
@@ -0,0 +1,3 @@
+package android
+
+import _ "b"
diff --git a/src/cmd/go/internal/imports/testdata/android/c_linux.go b/src/cmd/go/internal/imports/testdata/android/c_linux.go
new file mode 100644
index 0000000000..91624ce637
--- /dev/null
+++ b/src/cmd/go/internal/imports/testdata/android/c_linux.go
@@ -0,0 +1,3 @@
+package android
+
+import _ "c"
diff --git a/src/cmd/go/internal/imports/testdata/android/d_linux_arm64.go b/src/cmd/go/internal/imports/testdata/android/d_linux_arm64.go
new file mode 100644
index 0000000000..34e07df247
--- /dev/null
+++ b/src/cmd/go/internal/imports/testdata/android/d_linux_arm64.go
@@ -0,0 +1,3 @@
+package android
+
+import _ "d"
diff --git a/src/cmd/go/internal/imports/testdata/android/e.go b/src/cmd/go/internal/imports/testdata/android/e.go
new file mode 100644
index 0000000000..d9b2db769b
--- /dev/null
+++ b/src/cmd/go/internal/imports/testdata/android/e.go
@@ -0,0 +1,5 @@
+// +build android
+
+package android
+
+import _ "e"
diff --git a/src/cmd/go/internal/imports/testdata/android/f.go b/src/cmd/go/internal/imports/testdata/android/f.go
new file mode 100644
index 0000000000..281e4dd6b9
--- /dev/null
+++ b/src/cmd/go/internal/imports/testdata/android/f.go
@@ -0,0 +1,5 @@
+// +build linux
+
+package android
+
+import _ "f"
diff --git a/src/cmd/go/internal/imports/testdata/android/g.go b/src/cmd/go/internal/imports/testdata/android/g.go
new file mode 100644
index 0000000000..66a789c0ad
--- /dev/null
+++ b/src/cmd/go/internal/imports/testdata/android/g.go
@@ -0,0 +1,5 @@
+// +build !android
+
+package android
+
+import _ "g"
diff --git a/src/cmd/go/internal/imports/testdata/android/tags.txt b/src/cmd/go/internal/imports/testdata/android/tags.txt
new file mode 100644
index 0000000000..aaf5a6b91d
--- /dev/null
+++ b/src/cmd/go/internal/imports/testdata/android/tags.txt
@@ -0,0 +1 @@
+android arm64
\ No newline at end of file
diff --git a/src/cmd/go/internal/imports/testdata/android/want.txt b/src/cmd/go/internal/imports/testdata/android/want.txt
new file mode 100644
index 0000000000..0fdf397db0
--- /dev/null
+++ b/src/cmd/go/internal/imports/testdata/android/want.txt
@@ -0,0 +1,6 @@
+a
+b
+c
+d
+e
+f
diff --git a/src/cmd/go/internal/imports/testdata/star/tags.txt b/src/cmd/go/internal/imports/testdata/star/tags.txt
new file mode 100644
index 0000000000..f59ec20aab
--- /dev/null
+++ b/src/cmd/go/internal/imports/testdata/star/tags.txt
@@ -0,0 +1 @@
+*
\ No newline at end of file
diff --git a/src/cmd/go/internal/imports/testdata/star/want.txt b/src/cmd/go/internal/imports/testdata/star/want.txt
new file mode 100644
index 0000000000..139f5f4975
--- /dev/null
+++ b/src/cmd/go/internal/imports/testdata/star/want.txt
@@ -0,0 +1,4 @@
+import1
+import2
+import3
+import4
diff --git a/src/cmd/go/internal/imports/testdata/import1/x.go b/src/cmd/go/internal/imports/testdata/star/x.go
similarity index 100%
rename from src/cmd/go/internal/imports/testdata/import1/x.go
rename to src/cmd/go/internal/imports/testdata/star/x.go
diff --git a/src/cmd/go/internal/imports/testdata/import1/x1.go b/src/cmd/go/internal/imports/testdata/star/x1.go
similarity index 100%
rename from src/cmd/go/internal/imports/testdata/import1/x1.go
rename to src/cmd/go/internal/imports/testdata/star/x1.go
diff --git a/src/cmd/go/internal/imports/testdata/import1/x_darwin.go b/src/cmd/go/internal/imports/testdata/star/x_darwin.go
similarity index 100%
rename from src/cmd/go/internal/imports/testdata/import1/x_darwin.go
rename to src/cmd/go/internal/imports/testdata/star/x_darwin.go
diff --git a/src/cmd/go/internal/imports/testdata/import1/x_windows.go b/src/cmd/go/internal/imports/testdata/star/x_windows.go
similarity index 100%
rename from src/cmd/go/internal/imports/testdata/import1/x_windows.go
rename to src/cmd/go/internal/imports/testdata/star/x_windows.go