1 files changed, 39 insertions, 0 deletions
diff --git a/gopls/internal/lsp/analysis/simplifyslice/testdata/src/typeparams/typeparams.go b/gopls/internal/lsp/analysis/simplifyslice/testdata/src/typeparams/typeparams.go
new file mode 100644
index 000000000..69db3100a
--- /dev/null
+++ b/gopls/internal/lsp/analysis/simplifyslice/testdata/src/typeparams/typeparams.go
@@ -0,0 +1,39 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+//
+//go:build go1.18
+// +build go1.18
+
+package testdata
+
+type List[E any] []E
+
+// TODO(suzmue): add a test for generic slice expressions when https://github.com/golang/go/issues/48618 is closed.
+// type S interface{ ~[]int }
+
+var (
+	a [10]byte
+	b [20]float32
+	p List[int]
+
+	_ = p[0:]
+	_ = p[1:10]
+	_ = p[2:len(p)] // want "unneeded: len\\(p\\)"
+	_ = p[3:(len(p))]
+	_ = p[len(a) : len(p)-1]
+	_ = p[0:len(b)]
+	_ = p[2:len(p):len(p)]
+
+	_ = p[:]
+	_ = p[:10]
+	_ = p[:len(p)] // want "unneeded: len\\(p\\)"
+	_ = p[:(len(p))]
+	_ = p[:len(p)-1]
+	_ = p[:len(b)]
+	_ = p[:len(p):len(p)]
+)
+
+func foo[E any](a List[E]) {
+	_ = a[0:len(a)] // want "unneeded: len\\(a\\)"
+}