1 files changed, 56 insertions, 0 deletions
diff --git a/test/fixedbugs/issue48471.go b/test/fixedbugs/issue48471.go
new file mode 100644
index 0000000..062cb5a
--- /dev/null
+++ b/test/fixedbugs/issue48471.go
@@ -0,0 +1,56 @@
+// errorcheck
+
+// 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.
+
+package p
+
+type I interface{ M(int) }
+
+type T struct{}
+
+type T2 struct{}
+
+func (*T2) m(int)
+
+type T3 struct{}
+
+func (*T3) M(string) {}
+
+type T4 struct{}
+
+func (*T4) M(int)
+
+type T5 struct{}
+
+func (T5) m(int) {}
+
+type T6 struct{}
+
+func (T6) m(int) string { return "" }
+
+func f(I)
+
+func g() {
+	f(new(T)) // ERROR "cannot use new\(T\) \(.*type \*T\) as I value in argument to f: \*T does not implement I \(missing method M\)"
+
+	var i I
+	i = new(T)    // ERROR "cannot use new\(T\) \(.*type \*T\) as I value in assignment: \*T does not implement I \(missing method M\)"
+	i = I(new(T)) // ERROR "cannot convert new\(T\) \(.*type \*T\) to type I: \*T does not implement I \(missing method M\)"
+	i = new(T2)   // ERROR "cannot use new\(T2\) \(.*type \*T2\) as I value in assignment: \*T2 does not implement I \(missing method M\)\n\t\thave m\(int\)\n\t\twant M\(int\)"
+
+	i = new(T3) // ERROR "cannot use new\(T3\) \(.*type \*T3\) as I value in assignment: \*T3 does not implement I \(wrong type for method M\)\n\t\thave M\(string\)\n\t\twant M\(int\)"
+
+	i = T4{}   // ERROR "cannot use T4\{\} \(.*type T4\) as I value in assignment: T4 does not implement I \(method M has pointer receiver\)"
+	i = new(I) // ERROR "cannot use new\(I\) \(.*type \*I\) as I value in assignment: \*I does not implement I \(type \*I is pointer to interface, not interface\)"
+
+	_ = i.(*T2) // ERROR "impossible type assertion: i.\(\*T2\)\n\t\*T2 does not implement I \(missing method M\)\n\t\thave m\(int\)\n\t\twant M\(int\)"
+	_ = i.(*T3) // ERROR "impossible type assertion: i.\(\*T3\)\n\t\*T3 does not implement I \(wrong type for method M\)\n\t\thave M\(string\)\n\t\twant M\(int\)"
+	_ = i.(T5)  // ERROR ""impossible type assertion: i.\(T5\)\n\tT5 does not implement I \(missing method M\)\n\t\thave m\(int\)\n\t\twant M\(int\)"
+	_ = i.(T6)  // ERROR "impossible type assertion: i.\(T6\)\n\tT6 does not implement I \(missing method M\)\n\t\thave m\(int\) string\n\t\twant M\(int\)"
+
+	var t *T4
+	t = i // ERROR "cannot use i \(variable of type I\) as \*T4 value in assignment: need type assertion"
+	_ = i
+}