diff --git a/cue/builtins.go b/cue/builtins.go
index 80eec8a..c239e26 100644
--- a/cue/builtins.go
+++ b/cue/builtins.go
@@ -1673,16 +1673,6 @@
 				}()
 			},
 		}, {
-			Name:   "RotateLeft",
-			Params: []kind{intKind, intKind},
-			Result: intKind,
-			Func: func(c *callCtxt) {
-				x, k := c.uint64(0), c.int(1)
-				c.ret = func() interface{} {
-					return bits.RotateLeft64(x, k)
-				}()
-			},
-		}, {
 			Name:   "Reverse",
 			Params: []kind{intKind},
 			Result: intKind,
diff --git a/pkg/math/bits/manual.go b/pkg/math/bits/manual.go
index f7376a6..64ea5bb 100644
--- a/pkg/math/bits/manual.go
+++ b/pkg/math/bits/manual.go
@@ -107,12 +107,6 @@
 	return bits.OnesCount64(x)
 }
 
-// RotateLeft returns the value of x rotated left by (k mod UintSize) bits.
-// To rotate x right by k bits, call RotateLeft(x, -k).
-func RotateLeft(x uint64, k int) uint64 {
-	return bits.RotateLeft64(x, k)
-}
-
 // Reverse returns the value of x with its bits in reversed order.
 func Reverse(x uint64) uint64 {
 	return bits.Reverse64(x)
diff --git a/pkg/strings/strings.go b/pkg/strings/strings.go
index 73df2a1..a2077fb 100644
--- a/pkg/strings/strings.go
+++ b/pkg/strings/strings.go
@@ -16,7 +16,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:generate qgo -exclude=Rune$,Func$,^Map$,Special$,EqualFold,Byte,Title$,All$ extract strings
+//go:generate qgo -exclude=Rune$,Func$,^Map$,Special$,EqualFold,Byte,Title$,ToValidUTF8,All$ extract strings
 
 package strings
 
@@ -163,12 +163,6 @@
 	return strings.ToLower(s)
 }
 
-// ToValidUTF8 returns a copy of the string s with each run of invalid UTF-8 byte sequences
-// replaced by the replacement string, which may be empty.
-func ToValidUTF8(s, replacement string) string {
-	return strings.ToValidUTF8(s, replacement)
-}
-
 // Trim returns a slice of the string s with all leading and
 // trailing Unicode code points contained in cutset removed.
 func Trim(s string, cutset string) string {