1 files changed, 85 insertions, 0 deletions
diff --git a/gopls/internal/lsp/testdata/signature/signature.go b/gopls/internal/lsp/testdata/signature/signature.go
new file mode 100644
index 000000000..4e2b12bc4
--- /dev/null
+++ b/gopls/internal/lsp/testdata/signature/signature.go
@@ -0,0 +1,85 @@
+// Package signature has tests for signature help.
+package signature
+
+import (
+	"bytes"
+	"encoding/json"
+	"math/big"
+)
+
+func Foo(a string, b int) (c bool) {
+	return
+}
+
+func Bar(float64, ...byte) {
+}
+
+type myStruct struct{}
+
+func (*myStruct) foo(e *json.Decoder) (*big.Int, error) {
+	return nil, nil
+}
+
+type MyType struct{}
+
+type MyFunc func(foo int) string
+
+type Alias = int
+type OtherAlias = int
+type StringAlias = string
+
+func AliasSlice(a []*Alias) (b Alias)                                 { return 0 }
+func AliasMap(a map[*Alias]StringAlias) (b, c map[*Alias]StringAlias) { return nil, nil }
+func OtherAliasMap(a, b map[Alias]OtherAlias) map[Alias]OtherAlias    { return nil }
+
+func Qux() {
+	Foo("foo", 123) //@signature("(", "Foo(a string, b int) (c bool)", 0)
+	Foo("foo", 123) //@signature("123", "Foo(a string, b int) (c bool)", 1)
+	Foo("foo", 123) //@signature(",", "Foo(a string, b int) (c bool)", 0)
+	Foo("foo", 123) //@signature(" 1", "Foo(a string, b int) (c bool)", 1)
+	Foo("foo", 123) //@signature(")", "Foo(a string, b int) (c bool)", 1)
+
+	Bar(13.37, 0x13)       //@signature("13.37", "Bar(float64, ...byte)", 0)
+	Bar(13.37, 0x37)       //@signature("0x37", "Bar(float64, ...byte)", 1)
+	Bar(13.37, 1, 2, 3, 4) //@signature("4", "Bar(float64, ...byte)", 1)
+
+	fn := func(hi, there string) func(i int) rune {
+		return func(int) rune { return 0 }
+	}
+
+	fn("hi", "there")    //@signature("hi", "", 0)
+	fn("hi", "there")    //@signature(",", "fn(hi string, there string) func(i int) rune", 0)
+	fn("hi", "there")(1) //@signature("1", "func(i int) rune", 0)
+
+	fnPtr := &fn
+	(*fnPtr)("hi", "there") //@signature(",", "func(hi string, there string) func(i int) rune", 0)
+
+	var fnIntf interface{} = Foo
+	fnIntf.(func(string, int) bool)("hi", 123) //@signature("123", "func(string, int) bool", 1)
+
+	(&bytes.Buffer{}).Next(2) //@signature("2", "Next(n int) []byte", 0)
+
+	myFunc := MyFunc(func(n int) string { return "" })
+	myFunc(123) //@signature("123", "myFunc(foo int) string", 0)
+
+	var ms myStruct
+	ms.foo(nil) //@signature("nil", "foo(e *json.Decoder) (*big.Int, error)", 0)
+
+	_ = make([]int, 1, 2) //@signature("2", "make(t Type, size ...int) Type", 1)
+
+	Foo(myFunc(123), 456) //@signature("myFunc", "Foo(a string, b int) (c bool)", 0)
+	Foo(myFunc(123), 456) //@signature("123", "myFunc(foo int) string", 0)
+
+	panic("oops!")            //@signature(")", "panic(v interface{})", 0)
+	println("hello", "world") //@signature(",", "println(args ...Type)", 0)
+
+	Hello(func() {
+		//@signature("//", "", 0)
+	})
+
+	AliasSlice()    //@signature(")", "AliasSlice(a []*Alias) (b Alias)", 0)
+	AliasMap()      //@signature(")", "AliasMap(a map[*Alias]StringAlias) (b map[*Alias]StringAlias, c map[*Alias]StringAlias)", 0)
+	OtherAliasMap() //@signature(")", "OtherAliasMap(a map[Alias]OtherAlias, b map[Alias]OtherAlias) map[Alias]OtherAlias", 0)
+}
+
+func Hello(func()) {}