diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..9057e9b
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module github.com/modern-go/reflect2
+
+go 1.12
diff --git a/go_above_118.go b/go_above_118.go
new file mode 100644
index 0000000..2b4116f
--- /dev/null
+++ b/go_above_118.go
@@ -0,0 +1,23 @@
+//+build go1.18
+
+package reflect2
+
+import (
+	"unsafe"
+)
+
+// m escapes into the return value, but the caller of mapiterinit
+// doesn't let the return value escape.
+//go:noescape
+//go:linkname mapiterinit reflect.mapiterinit
+func mapiterinit(rtype unsafe.Pointer, m unsafe.Pointer, it *hiter)
+
+func (type2 *UnsafeMapType) UnsafeIterate(obj unsafe.Pointer) MapIterator {
+	var it hiter
+	mapiterinit(type2.rtype, *(*unsafe.Pointer)(obj), &it)
+	return &UnsafeMapIterator{
+		hiter:      &it,
+		pKeyRType:  type2.pKeyRType,
+		pElemRType: type2.pElemRType,
+	}
+}
\ No newline at end of file
diff --git a/go_below_118.go b/go_below_118.go
new file mode 100644
index 0000000..00003db
--- /dev/null
+++ b/go_below_118.go
@@ -0,0 +1,21 @@
+//+build !go1.18
+
+package reflect2
+
+import (
+	"unsafe"
+)
+
+// m escapes into the return value, but the caller of mapiterinit
+// doesn't let the return value escape.
+//go:noescape
+//go:linkname mapiterinit reflect.mapiterinit
+func mapiterinit(rtype unsafe.Pointer, m unsafe.Pointer) (val *hiter)
+
+func (type2 *UnsafeMapType) UnsafeIterate(obj unsafe.Pointer) MapIterator {
+	return &UnsafeMapIterator{
+		hiter:      mapiterinit(type2.rtype, *(*unsafe.Pointer)(obj)),
+		pKeyRType:  type2.pKeyRType,
+		pElemRType: type2.pElemRType,
+	}
+}
\ No newline at end of file
diff --git a/test.sh b/test.sh
deleted file mode 100755
index 3d2b976..0000000
--- a/test.sh
+++ /dev/null
@@ -1,12 +0,0 @@
-#!/usr/bin/env bash
-
-set -e
-echo "" > coverage.txt
-
-for d in $(go list github.com/modern-go/reflect2-tests/... | grep -v vendor); do
-    go test -coverprofile=profile.out -coverpkg=github.com/modern-go/reflect2 $d
-    if [ -f profile.out ]; then
-        cat profile.out >> coverage.txt
-        rm profile.out
-    fi
-done
diff --git a/unsafe_link.go b/unsafe_link.go
index 57229c8..b49f614 100644
--- a/unsafe_link.go
+++ b/unsafe_link.go
@@ -19,18 +19,12 @@ func typedslicecopy(elemType unsafe.Pointer, dst, src sliceHeader) int
 
 //go:linkname mapassign reflect.mapassign
 //go:noescape
-func mapassign(rtype unsafe.Pointer, m unsafe.Pointer, key, val unsafe.Pointer)
+func mapassign(rtype unsafe.Pointer, m unsafe.Pointer, key unsafe.Pointer, val unsafe.Pointer)
 
 //go:linkname mapaccess reflect.mapaccess
 //go:noescape
 func mapaccess(rtype unsafe.Pointer, m unsafe.Pointer, key unsafe.Pointer) (val unsafe.Pointer)
 
-// m escapes into the return value, but the caller of mapiterinit
-// doesn't let the return value escape.
-//go:noescape
-//go:linkname mapiterinit reflect.mapiterinit
-func mapiterinit(rtype unsafe.Pointer, m unsafe.Pointer) *hiter
-
 //go:noescape
 //go:linkname mapiternext reflect.mapiternext
 func mapiternext(it *hiter)
@@ -42,9 +36,21 @@ func ifaceE2I(rtype unsafe.Pointer, src interface{}, dst unsafe.Pointer)
 // If you modify hiter, also change cmd/internal/gc/reflect.go to indicate
 // the layout of this structure.
 type hiter struct {
-	key   unsafe.Pointer // Must be in first position.  Write nil to indicate iteration end (see cmd/internal/gc/range.go).
-	value unsafe.Pointer // Must be in second position (see cmd/internal/gc/range.go).
-	// rest fields are ignored
+	key         unsafe.Pointer
+	value       unsafe.Pointer
+	t           unsafe.Pointer
+	h           unsafe.Pointer
+	buckets     unsafe.Pointer
+	bptr        unsafe.Pointer
+	overflow    *[]unsafe.Pointer
+	oldoverflow *[]unsafe.Pointer
+	startBucket uintptr
+	offset      uint8
+	wrapped     bool
+	B           uint8
+	i           uint8
+	bucket      uintptr
+	checkBucket uintptr
 }
 
 // add returns p+x.
diff --git a/unsafe_map.go b/unsafe_map.go
index f2e76e6..37872da 100644
--- a/unsafe_map.go
+++ b/unsafe_map.go
@@ -107,14 +107,6 @@ func (type2 *UnsafeMapType) Iterate(obj interface{}) MapIterator {
 	return type2.UnsafeIterate(objEFace.data)
 }
 
-func (type2 *UnsafeMapType) UnsafeIterate(obj unsafe.Pointer) MapIterator {
-	return &UnsafeMapIterator{
-		hiter:      mapiterinit(type2.rtype, *(*unsafe.Pointer)(obj)),
-		pKeyRType:  type2.pKeyRType,
-		pElemRType: type2.pElemRType,
-	}
-}
-
 type UnsafeMapIterator struct {
 	*hiter
 	pKeyRType  unsafe.Pointer