diff --git a/types/opt/bool.go b/types/opt/bool.go
index 66ff1bd82..ca9c048d5 100644
--- a/types/opt/bool.go
+++ b/types/opt/bool.go
@@ -87,21 +87,15 @@ func (b Bool) MarshalJSON() ([]byte, error) {
 }
 
 func (b *Bool) UnmarshalJSON(j []byte) error {
-	// Note: written with a bunch of ifs instead of a switch
-	// because I'm sure the Go compiler optimizes away these
-	// []byte->string allocations in an == comparison, but I'm too
-	// lazy to check whether that's true in a switch also.
-	if string(j) == "true" {
+	switch string(j) {
+	case "true":
 		*b = "true"
-		return nil
-	}
-	if string(j) == "false" {
+	case "false":
 		*b = "false"
-		return nil
-	}
-	if string(j) == "null" {
+	case "null":
 		*b = "unset"
-		return nil
+	default:
+		return fmt.Errorf("invalid opt.Bool value %q", j)
 	}
-	return fmt.Errorf("invalid opt.Bool value %q", j)
+	return nil
 }
diff --git a/types/opt/bool_test.go b/types/opt/bool_test.go
index 2dc2d1707..92ba275e1 100644
--- a/types/opt/bool_test.go
+++ b/types/opt/bool_test.go
@@ -119,3 +119,11 @@ func TestBoolEqualBool(t *testing.T) {
 		}
 	}
 }
+
+func TestUnmarshalAlloc(t *testing.T) {
+	b := json.Unmarshaler(new(Bool))
+	n := testing.AllocsPerRun(10, func() { b.UnmarshalJSON(trueBytes) })
+	if n > 0 {
+		t.Errorf("got %v allocs, want 0", n)
+	}
+}