diff --git a/src/cmd/compile/internal/types2/builtins.go b/src/cmd/compile/internal/types2/builtins.go
index 1bd2fdce06..b504c2bd5d 100644
--- a/src/cmd/compile/internal/types2/builtins.go
+++ b/src/cmd/compile/internal/types2/builtins.go
@@ -623,7 +623,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 			return
 		}
 
-		if hasVarSize(x.typ) {
+		if hasVarSize(x.typ, nil) {
 			x.mode = value
 			if check.Types != nil {
 				check.recordBuiltinType(call.Fun, makeSig(Typ[Uintptr], x.typ))
@@ -687,7 +687,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 		// the part of the struct which is variable-sized. This makes both the rules
 		// simpler and also permits (or at least doesn't prevent) a compiler from re-
 		// arranging struct fields if it wanted to.
-		if hasVarSize(base) {
+		if hasVarSize(base, nil) {
 			x.mode = value
 			if check.Types != nil {
 				check.recordBuiltinType(call.Fun, makeSig(Typ[Uintptr], obj.Type()))
@@ -706,7 +706,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 			return
 		}
 
-		if hasVarSize(x.typ) {
+		if hasVarSize(x.typ, nil) {
 			x.mode = value
 			if check.Types != nil {
 				check.recordBuiltinType(call.Fun, makeSig(Typ[Uintptr], x.typ))
@@ -788,14 +788,32 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 	return true
 }
 
-// hasVarSize reports if the size of type t is variable due to type parameters.
-func hasVarSize(t Type) bool {
+// hasVarSize reports if the size of type t is variable due to type parameters
+// or if the type is infinitely-sized due to a cycle for which the type has not
+// yet been checked.
+func hasVarSize(t Type, seen map[*Named]bool) (varSized bool) {
+	// Cycles are only possible through *Named types.
+	// The seen map is used to detect cycles and track
+	// the results of previously seen types.
+	if named, _ := t.(*Named); named != nil {
+		if v, ok := seen[named]; ok {
+			return v
+		}
+		if seen == nil {
+			seen = make(map[*Named]bool)
+		}
+		seen[named] = true // possibly cyclic until proven otherwise
+		defer func() {
+			seen[named] = varSized // record final determination for named
+		}()
+	}
+
 	switch u := under(t).(type) {
 	case *Array:
-		return hasVarSize(u.elem)
+		return hasVarSize(u.elem, seen)
 	case *Struct:
 		for _, f := range u.fields {
-			if hasVarSize(f.typ) {
+			if hasVarSize(f.typ, seen) {
 				return true
 			}
 		}
diff --git a/src/cmd/compile/internal/types2/testdata/fixedbugs/issue52915.go b/src/cmd/compile/internal/types2/testdata/fixedbugs/issue52915.go
new file mode 100644
index 0000000000..2c38e5bcca
--- /dev/null
+++ b/src/cmd/compile/internal/types2/testdata/fixedbugs/issue52915.go
@@ -0,0 +1,23 @@
+// 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
+
+import "unsafe"
+
+type T[P any] struct {
+	T /* ERROR illegal cycle */ [P]
+}
+
+func _[P any]() {
+	_ = unsafe.Sizeof(T[int]{})
+	_ = unsafe.Sizeof(struct{ T[int] }{})
+
+	_ = unsafe.Sizeof(T[P]{})
+	_ = unsafe.Sizeof(struct{ T[P] }{})
+}
+
+// TODO(gri) This is a follow-on error due to T[int] being invalid.
+//           We should try to avoid it.
+const _ = unsafe /* ERROR not constant */ .Sizeof(T[int]{})
diff --git a/src/go/types/builtins.go b/src/go/types/builtins.go
index 414c2c3ea0..463d814a2f 100644
--- a/src/go/types/builtins.go
+++ b/src/go/types/builtins.go
@@ -632,7 +632,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 			return
 		}
 
-		if hasVarSize(x.typ) {
+		if hasVarSize(x.typ, nil) {
 			x.mode = value
 			if check.Types != nil {
 				check.recordBuiltinType(call.Fun, makeSig(Typ[Uintptr], x.typ))
@@ -696,7 +696,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 		// the part of the struct which is variable-sized. This makes both the rules
 		// simpler and also permits (or at least doesn't prevent) a compiler from re-
 		// arranging struct fields if it wanted to.
-		if hasVarSize(base) {
+		if hasVarSize(base, nil) {
 			x.mode = value
 			if check.Types != nil {
 				check.recordBuiltinType(call.Fun, makeSig(Typ[Uintptr], obj.Type()))
@@ -715,7 +715,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 			return
 		}
 
-		if hasVarSize(x.typ) {
+		if hasVarSize(x.typ, nil) {
 			x.mode = value
 			if check.Types != nil {
 				check.recordBuiltinType(call.Fun, makeSig(Typ[Uintptr], x.typ))
@@ -797,14 +797,32 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 	return true
 }
 
-// hasVarSize reports if the size of type t is variable due to type parameters.
-func hasVarSize(t Type) bool {
+// hasVarSize reports if the size of type t is variable due to type parameters
+// or if the type is infinitely-sized due to a cycle for which the type has not
+// yet been checked.
+func hasVarSize(t Type, seen map[*Named]bool) (varSized bool) {
+	// Cycles are only possible through *Named types.
+	// The seen map is used to detect cycles and track
+	// the results of previously seen types.
+	if named, _ := t.(*Named); named != nil {
+		if v, ok := seen[named]; ok {
+			return v
+		}
+		if seen == nil {
+			seen = make(map[*Named]bool)
+		}
+		seen[named] = true // possibly cyclic until proven otherwise
+		defer func() {
+			seen[named] = varSized // record final determination for named
+		}()
+	}
+
 	switch u := under(t).(type) {
 	case *Array:
-		return hasVarSize(u.elem)
+		return hasVarSize(u.elem, seen)
 	case *Struct:
 		for _, f := range u.fields {
-			if hasVarSize(f.typ) {
+			if hasVarSize(f.typ, seen) {
 				return true
 			}
 		}
diff --git a/src/go/types/testdata/fixedbugs/issue52915.go b/src/go/types/testdata/fixedbugs/issue52915.go
new file mode 100644
index 0000000000..2c38e5bcca
--- /dev/null
+++ b/src/go/types/testdata/fixedbugs/issue52915.go
@@ -0,0 +1,23 @@
+// 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
+
+import "unsafe"
+
+type T[P any] struct {
+	T /* ERROR illegal cycle */ [P]
+}
+
+func _[P any]() {
+	_ = unsafe.Sizeof(T[int]{})
+	_ = unsafe.Sizeof(struct{ T[int] }{})
+
+	_ = unsafe.Sizeof(T[P]{})
+	_ = unsafe.Sizeof(struct{ T[P] }{})
+}
+
+// TODO(gri) This is a follow-on error due to T[int] being invalid.
+//           We should try to avoid it.
+const _ = unsafe /* ERROR not constant */ .Sizeof(T[int]{})