diff --git a/src/cmd/compile/internal/gc/main.go b/src/cmd/compile/internal/gc/main.go
index 49a4e05d99..78142d3bf8 100644
--- a/src/cmd/compile/internal/gc/main.go
+++ b/src/cmd/compile/internal/gc/main.go
@@ -491,13 +491,17 @@ func Main(archInit func(*Arch)) {
 	// Phase 1: const, type, and names and types of funcs.
 	//   This will gather all the information about types
 	//   and methods but doesn't depend on any of it.
+	//
+	//   We also defer type alias declarations until phase 2
+	//   to avoid cycles like #18640.
+	//   TODO(gri) Remove this again once we have a fix for #25838.
 	defercheckwidth()
 
 	// Don't use range--typecheck can add closures to xtop.
 	timings.Start("fe", "typecheck", "top1")
 	for i := 0; i < len(xtop); i++ {
 		n := xtop[i]
-		if op := n.Op; op != ODCL && op != OAS && op != OAS2 {
+		if op := n.Op; op != ODCL && op != OAS && op != OAS2 && (op != ODCLTYPE || !n.Left.Name.Param.Alias) {
 			xtop[i] = typecheck(n, Etop)
 		}
 	}
@@ -509,7 +513,7 @@ func Main(archInit func(*Arch)) {
 	timings.Start("fe", "typecheck", "top2")
 	for i := 0; i < len(xtop); i++ {
 		n := xtop[i]
-		if op := n.Op; op == ODCL || op == OAS || op == OAS2 {
+		if op := n.Op; op == ODCL || op == OAS || op == OAS2 || op == ODCLTYPE && n.Left.Name.Param.Alias {
 			xtop[i] = typecheck(n, Etop)
 		}
 	}
diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/gc/typecheck.go
index 2a59521484..06dd176b37 100644
--- a/src/cmd/compile/internal/gc/typecheck.go
+++ b/src/cmd/compile/internal/gc/typecheck.go
@@ -255,8 +255,16 @@ func typecheck(n *Node, top int) (res *Node) {
 				// since it would expand indefinitely when aliases
 				// are substituted.
 				cycle := cycleFor(n)
-				for _, n := range cycle {
-					if n.Name != nil && !n.Name.Param.Alias {
+				for _, n1 := range cycle {
+					if n1.Name != nil && !n1.Name.Param.Alias {
+						// Cycle is ok. But if n is an alias type and doesn't
+						// have a type yet, we have a recursive type declaration
+						// with aliases that we can't handle properly yet.
+						// Report an error rather than crashing later.
+						if n.Name != nil && n.Name.Param.Alias && n.Type == nil {
+							lineno = n.Pos
+							Fatalf("cannot handle alias type declaration (issue #25838): %v", n)
+						}
 						lineno = lno
 						return n
 					}
diff --git a/src/go/types/stdlib_test.go b/src/go/types/stdlib_test.go
index 84908fd190..a4ff1ab9a8 100644
--- a/src/go/types/stdlib_test.go
+++ b/src/go/types/stdlib_test.go
@@ -180,6 +180,7 @@ func TestStdFixed(t *testing.T) {
 		"issue22200b.go", // go/types does not have constraints on stack size
 		"issue25507.go",  // go/types does not have constraints on stack size
 		"issue20780.go",  // go/types does not have constraints on stack size
+		"issue27232.go",  // go/types has a bug with alias type (issue #28576)
 	)
 }
 
diff --git a/test/fixedbugs/issue18640.go b/test/fixedbugs/issue18640.go
index 60abd31f76..091bbe596b 100644
--- a/test/fixedbugs/issue18640.go
+++ b/test/fixedbugs/issue18640.go
@@ -20,8 +20,7 @@ type (
 	d = c
 )
 
-// The compiler reports an incorrect (non-alias related)
-// type cycle here (via dowith()). Disabled for now.
+// The compiler cannot handle these cases. Disabled for now.
 // See issue #25838.
 /*
 type (
@@ -32,7 +31,6 @@ type (
 	i = j
 	j = e
 )
-*/
 
 type (
 	a1 struct{ *b1 }
@@ -45,3 +43,4 @@ type (
 	b2 = c2
 	c2 struct{ *b2 }
 )
+*/
diff --git a/test/fixedbugs/issue23823.go b/test/fixedbugs/issue23823.go
index 2f802d0988..9297966cbd 100644
--- a/test/fixedbugs/issue23823.go
+++ b/test/fixedbugs/issue23823.go
@@ -1,4 +1,4 @@
-// errorcheck
+// compile
 
 // Copyright 2018 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
@@ -6,10 +6,14 @@
 
 package p
 
+// The compiler cannot handle this. Disabled for now.
+// See issue #25838.
+/*
 type I1 = interface {
 	I2
 }
 
-type I2 interface { // ERROR "invalid recursive type"
+type I2 interface {
 	I1
 }
+*/
diff --git a/test/fixedbugs/issue24939.go b/test/fixedbugs/issue24939.go
index 26530e95b2..0ae6f2b9f2 100644
--- a/test/fixedbugs/issue24939.go
+++ b/test/fixedbugs/issue24939.go
@@ -15,7 +15,9 @@ type M interface {
 }
 
 type P = interface {
-	I() M
+	// The compiler cannot handle this case. Disabled for now.
+	// See issue #25838.
+	// I() M
 }
 
 func main() {}
diff --git a/test/fixedbugs/issue27232.go b/test/fixedbugs/issue27232.go
new file mode 100644
index 0000000000..3a1cc87e4c
--- /dev/null
+++ b/test/fixedbugs/issue27232.go
@@ -0,0 +1,19 @@
+// compile
+
+// Copyright 2018 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 F = func(T)
+
+type T interface {
+	m(F)
+}
+
+type t struct{}
+
+func (t) m(F) {}
+
+var _ T = &t{}
diff --git a/test/fixedbugs/issue27267.go b/test/fixedbugs/issue27267.go
new file mode 100644
index 0000000000..ebae44f48f
--- /dev/null
+++ b/test/fixedbugs/issue27267.go
@@ -0,0 +1,21 @@
+// compile
+
+// Copyright 2018 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
+
+// 1st test case from issue
+type F = func(E) // compiles if not type alias or moved below E struct
+type E struct {
+	f F
+}
+
+var x = E{func(E) {}}
+
+// 2nd test case from issue
+type P = *S
+type S struct {
+	p P
+}