diff --git a/src/cmd/compile/internal/gc/walk.go b/src/cmd/compile/internal/gc/walk.go
index 6a00287b2d4..da43781212c 100644
--- a/src/cmd/compile/internal/gc/walk.go
+++ b/src/cmd/compile/internal/gc/walk.go
@@ -3561,7 +3561,10 @@ func walkinrange(n *Node, init *Nodes) *Node {
 	cmp.Lineno = n.Lineno
 	cmp = addinit(cmp, l.Ninit.Slice())
 	cmp = addinit(cmp, r.Ninit.Slice())
+	// Typecheck the AST rooted at cmp...
 	cmp = typecheck(cmp, Erv)
+	// ...but then reset cmp's type to match n's type.
+	cmp.Type = n.Type
 	cmp = walkexpr(cmp, init)
 	return cmp
 }
diff --git a/test/fixedbugs/issue17551.go b/test/fixedbugs/issue17551.go
new file mode 100644
index 00000000000..b8751ab42dc
--- /dev/null
+++ b/test/fixedbugs/issue17551.go
@@ -0,0 +1,21 @@
+// compile
+
+// Copyright 2016 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.
+
+// Issue 17551: inrange optimization failed to preserve type information.
+
+package main
+
+import "fmt"
+
+func main() {
+	_, x := X()
+	fmt.Printf("x = %v\n", x)
+}
+
+func X() (i int, ok bool) {
+	ii := int(1)
+	return ii, 0 <= ii && ii <= 0x7fffffff
+}