go source for verification 2026-05-22

test/fixedbugs/issue56103.go

@@ -0,0 +1,46 @@
+// errorcheck
+
+// Copyright 2022 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
+
+// Self recursion.
+type i interface{ m() interface{ i } } // ERROR "invalid recursive type"
+type _ interface{ i }                  // no redundant error
+
+// Mutual recursion.
+type j interface{ m() interface{ k } } // ERROR "invalid recursive type"
+type k interface{ m() interface{ j } }
+
+// Both self and mutual recursion.
+type (
+	a interface { // ERROR "invalid recursive type"
+		m() interface {
+			a
+			b
+		}
+	}
+	b interface {
+		m() interface {
+			a
+			b
+		}
+	}
+)
+
+// Self recursion through other types.
+func _() { type i interface{ m() *interface{ i } } }        // ERROR "invalid recursive type"
+func _() { type i interface{ m() []interface{ i } } }       // ERROR "invalid recursive type"
+func _() { type i interface{ m() [0]interface{ i } } }      // ERROR "invalid recursive type"
+func _() { type i interface{ m() chan interface{ i } } }    // ERROR "invalid recursive type"
+func _() { type i interface{ m() map[interface{ i }]int } } // ERROR "invalid recursive type"
+func _() { type i interface{ m() map[int]interface{ i } } } // ERROR "invalid recursive type"
+func _() { type i interface{ m() func(interface{ i }) } }   // ERROR "invalid recursive type"
+func _() { type i interface{ m() func() interface{ i } } }  // ERROR "invalid recursive type"
+func _() {
+	type i interface { // ERROR "invalid recursive type"
+		m() struct{ i interface{ i } }
+	}
+}