diff --git a/src/cmd/compile/internal/base/debug.go b/src/cmd/compile/internal/base/debug.go
index a85f0139fc..aadd950a0a 100644
--- a/src/cmd/compile/internal/base/debug.go
+++ b/src/cmd/compile/internal/base/debug.go
@@ -36,7 +36,6 @@ type DebugFlags struct {
 	Gossahash             string `help:"hash value for use in debugging the compiler"`
 	InlFuncsWithClosures  int    `help:"allow functions with closures to be inlined" concurrent:"ok"`
 	InlStaticInit         int    `help:"allow static initialization of inlined calls" concurrent:"ok"`
-	InterfaceCycles       int    `help:"allow anonymous interface cycles"`
 	Libfuzzer             int    `help:"enable coverage instrumentation for libfuzzer"`
 	LoopVar               int    `help:"shared (0, default), 1 (private loop variables), 2, private + log"`
 	LoopVarHash           string `help:"for debugging changes in loop behavior. Overrides experiment and loopvar flag."`
diff --git a/src/cmd/compile/internal/noder/irgen.go b/src/cmd/compile/internal/noder/irgen.go
index 46511d1f97..d909f3467b 100644
--- a/src/cmd/compile/internal/noder/irgen.go
+++ b/src/cmd/compile/internal/noder/irgen.go
@@ -92,23 +92,22 @@ func checkFiles(m posMap, noders []*noder) (*types2.Package, *types2.Info) {
 	}
 
 	// Check for anonymous interface cycles (#56103).
-	if base.Debug.InterfaceCycles == 0 {
-		var f cycleFinder
-		for _, file := range files {
-			syntax.Inspect(file, func(n syntax.Node) bool {
-				if n, ok := n.(*syntax.InterfaceType); ok {
-					if f.hasCycle(n.GetTypeInfo().Type.(*types2.Interface)) {
-						base.ErrorfAt(m.makeXPos(n.Pos()), errors.InvalidTypeCycle, "invalid recursive type: anonymous interface refers to itself (see https://go.dev/issue/56103)")
+	// TODO(gri) move this code into the type checkers (types2 and go/types)
+	var f cycleFinder
+	for _, file := range files {
+		syntax.Inspect(file, func(n syntax.Node) bool {
+			if n, ok := n.(*syntax.InterfaceType); ok {
+				if f.hasCycle(n.GetTypeInfo().Type.(*types2.Interface)) {
+					base.ErrorfAt(m.makeXPos(n.Pos()), errors.InvalidTypeCycle, "invalid recursive type: anonymous interface refers to itself (see https://go.dev/issue/56103)")
 
-						for typ := range f.cyclic {
-							f.cyclic[typ] = false // suppress duplicate errors
-						}
+					for typ := range f.cyclic {
+						f.cyclic[typ] = false // suppress duplicate errors
 					}
-					return false
 				}
-				return true
-			})
-		}
+				return false
+			}
+			return true
+		})
 	}
 	base.ExitIfErrors()
 
diff --git a/src/cmd/compile/internal/types2/stdlib_test.go b/src/cmd/compile/internal/types2/stdlib_test.go
index 7c14e3476e..405af78572 100644
--- a/src/cmd/compile/internal/types2/stdlib_test.go
+++ b/src/cmd/compile/internal/types2/stdlib_test.go
@@ -311,6 +311,7 @@ func TestStdFixed(t *testing.T) {
 
 	testTestDir(t, filepath.Join(testenv.GOROOT(t), "test", "fixedbugs"),
 		"bug248.go", "bug302.go", "bug369.go", // complex test instructions - ignore
+		"bug398.go",      // types2 doesn't check for anonymous interface cycles (go.dev/issue/56103)
 		"issue6889.go",   // gc-specific test
 		"issue11362.go",  // canonical import path check
 		"issue16369.go",  // types2 handles this correctly - not an issue
diff --git a/src/go/types/stdlib_test.go b/src/go/types/stdlib_test.go
index f90f9388c2..a89cd858db 100644
--- a/src/go/types/stdlib_test.go
+++ b/src/go/types/stdlib_test.go
@@ -312,6 +312,7 @@ func TestStdFixed(t *testing.T) {
 
 	testTestDir(t, filepath.Join(testenv.GOROOT(t), "test", "fixedbugs"),
 		"bug248.go", "bug302.go", "bug369.go", // complex test instructions - ignore
+		"bug398.go",      // go/types doesn't check for anonymous interface cycles (go.dev/issue/56103)
 		"issue6889.go",   // gc-specific test
 		"issue11362.go",  // canonical import path check
 		"issue16369.go",  // go/types handles this correctly - not an issue
diff --git a/test/fixedbugs/bug398.go b/test/fixedbugs/bug398.go
index db3e43c7f9..2b00f6074d 100644
--- a/test/fixedbugs/bug398.go
+++ b/test/fixedbugs/bug398.go
@@ -1,4 +1,4 @@
-// compile -d=interfacecycles
+// errorcheck
 
 // Copyright 2012 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
@@ -11,11 +11,11 @@ package p
 
 // exported interfaces
 
-type I1 interface {
+type I1 interface { // ERROR "invalid recursive type: anonymous interface refers to itself"
       F() interface{I1}
 }
 
-type I2 interface {
+type I2 interface { // ERROR "invalid recursive type: anonymous interface refers to itself"
       F() interface{I2}
 }
 
@@ -28,11 +28,11 @@ func F() bool {
 
 // non-exported interfaces
 
-type i1 interface {
+type i1 interface { // ERROR "invalid recursive type: anonymous interface refers to itself"
       F() interface{i1}
 }
 
-type i2 interface {
+type i2 interface { // ERROR "invalid recursive type: anonymous interface refers to itself"
       F() interface{i2}
 }
 
diff --git a/test/fixedbugs/issue16369.go b/test/fixedbugs/issue16369.go
index 3a7bb7eaed..86d0ce645d 100644
--- a/test/fixedbugs/issue16369.go
+++ b/test/fixedbugs/issue16369.go
@@ -1,4 +1,4 @@
-// compile -d=interfacecycles
+// errorcheck
 
 // Copyright 2016 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
@@ -6,7 +6,7 @@
 
 package p
 
-type T interface {
+type T interface { // ERROR "invalid recursive type: anonymous interface refers to itself"
 	M(interface {
 		T
 	})