diff --git a/go/analysis/passes/errorsas/errorsas_test.go b/go/analysis/passes/errorsas/errorsas_test.go
index 5ef8668..7908e89 100644
--- a/go/analysis/passes/errorsas/errorsas_test.go
+++ b/go/analysis/passes/errorsas/errorsas_test.go
@@ -12,9 +12,14 @@
 
 	"golang.org/x/tools/go/analysis/analysistest"
 	"golang.org/x/tools/go/analysis/passes/errorsas"
+	"golang.org/x/tools/internal/typeparams"
 )
 
 func Test(t *testing.T) {
 	testdata := analysistest.TestData()
-	analysistest.Run(t, testdata, errorsas.Analyzer, "a")
+	tests := []string{"a"}
+	if typeparams.Enabled {
+		tests = append(tests, "typeparams")
+	}
+	analysistest.Run(t, testdata, errorsas.Analyzer, tests...)
 }
diff --git a/go/analysis/passes/errorsas/testdata/src/typeparams/typeparams.go b/go/analysis/passes/errorsas/testdata/src/typeparams/typeparams.go
new file mode 100644
index 0000000..8b020ca
--- /dev/null
+++ b/go/analysis/passes/errorsas/testdata/src/typeparams/typeparams.go
@@ -0,0 +1,37 @@
+// Copyright 2019 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.
+
+// This file contains tests for the errorsas checker.
+
+package a
+
+import "errors"
+
+type myError[T any] T
+
+func (myError[T]) Error() string { return "" }
+
+type twice[T any] struct {
+	t T
+}
+
+func perr[T any]() *T { return nil }
+
+func two[T any]() (error, *T) { return nil, nil }
+
+func _[E error](e E) {
+	var (
+		m  myError[int]
+		tw twice[myError[int]]
+	)
+	errors.As(nil, &e)
+	errors.As(nil, &m)            // *T where T implemements error
+	errors.As(nil, &tw.t)         // *T where T implements error
+	errors.As(nil, perr[error]()) // *error, via a call
+
+	errors.As(nil, e)    // want `second argument to errors.As must be a non-nil pointer to either a type that implements error, or to any interface type`
+	errors.As(nil, m)    // want `second argument to errors.As must be a non-nil pointer to either a type that implements error, or to any interface type`
+	errors.As(nil, tw.t) // want `second argument to errors.As must be a non-nil pointer to either a type that implements error, or to any interface type`
+	errors.As(two[error]())
+}