1 files changed, 54 insertions, 0 deletions
diff --git a/src/pkg/go/printer/testdata/declarations.input b/src/pkg/go/printer/testdata/declarations.input
index d74cff25d..455c0c6c1 100644
--- a/src/pkg/go/printer/testdata/declarations.input
+++ b/src/pkg/go/printer/testdata/declarations.input
@@ -667,6 +667,35 @@ var _ = map[int]int{
 	abcde: a, // align with previous line
 }
 
+// alignment of map composite entries: test cases from issue 3965
+// aligned
+var _ = T1{
+	a:                    x,
+	b:                    y,
+	cccccccccccccccccccc: z,
+}
+
+// not aligned
+var _ = T2{
+	a: x,
+	b: y,
+	ccccccccccccccccccccc: z,
+}
+
+// aligned
+var _ = T3{
+	aaaaaaaaaaaaaaaaaaaa: x,
+	b:                    y,
+	c:                    z,
+}
+
+// not aligned
+var _ = T4{
+	aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa: x,
+	b:                                       y,
+	c:                                       z,
+}
+
 
 func _() {
 	var _ = T{
@@ -867,3 +896,28 @@ p, q,
 r string,
 		x ...int)
 }
+
+// omit superfluous parentheses in parameter lists
+func _((int))
+func _((((((int))))))
+func _(x (int))
+func _(x (((((int))))))
+func _(x, y (int))
+func _(x, y (((((int))))))
+
+func _() (int)
+func _() ((int))
+func _() ((((((int))))))
+
+func _() (x int)
+func _() (x (int))
+func _() (x (((((int))))))
+
+// special cases: some channel types require parentheses
+func _(x chan(<-chan int))
+func _(x (chan(<-chan int)))
+func _(x ((((chan(<-chan int))))))
+
+func _(x chan<-(chan int))
+func _(x (chan<-(chan int)))
+func _(x ((((chan<-(chan int))))))