diff --git a/src/cmd/compile/internal/gc/dep_test.go b/src/cmd/compile/internal/gc/dep_test.go
index c1dac933865..a185bc9f547 100644
--- a/src/cmd/compile/internal/gc/dep_test.go
+++ b/src/cmd/compile/internal/gc/dep_test.go
@@ -18,7 +18,7 @@ func TestDeps(t *testing.T) {
 	}
 	for _, dep := range strings.Fields(strings.Trim(string(out), "[]")) {
 		switch dep {
-		case "go/build", "go/token":
+		case "go/build", "go/scanner":
 			t.Errorf("undesired dependency on %q", dep)
 		}
 	}
diff --git a/src/cmd/dist/buildtool.go b/src/cmd/dist/buildtool.go
index 37b3d45977a..e39f284db56 100644
--- a/src/cmd/dist/buildtool.go
+++ b/src/cmd/dist/buildtool.go
@@ -96,6 +96,7 @@ var bootstrapDirs = []string{
 	"debug/elf",
 	"debug/macho",
 	"debug/pe",
+	"go/constant",
 	"internal/goversion",
 	"internal/race",
 	"internal/unsafeheader",
@@ -103,6 +104,7 @@ var bootstrapDirs = []string{
 	"math/big",
 	"math/bits",
 	"sort",
+	"strconv",
 }
 
 // File prefixes that are ignored by go/build anyway, and cause
diff --git a/src/strconv/bytealg.go b/src/strconv/bytealg.go
new file mode 100644
index 00000000000..7f66f2a8bbc
--- /dev/null
+++ b/src/strconv/bytealg.go
@@ -0,0 +1,14 @@
+// Copyright 2009 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.
+
+// +build !compiler_bootstrap
+
+package strconv
+
+import "internal/bytealg"
+
+// contains reports whether the string contains the byte c.
+func contains(s string, c byte) bool {
+	return bytealg.IndexByteString(s, c) != -1
+}
diff --git a/src/strconv/bytealg_bootstrap.go b/src/strconv/bytealg_bootstrap.go
new file mode 100644
index 00000000000..a3a547d1b63
--- /dev/null
+++ b/src/strconv/bytealg_bootstrap.go
@@ -0,0 +1,17 @@
+// Copyright 2020 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.
+
+// +build compiler_bootstrap
+
+package strconv
+
+// contains reports whether the string contains the byte c.
+func contains(s string, c byte) bool {
+	for i := 0; i < len(s); i++ {
+		if s[i] == c {
+			return true
+		}
+	}
+	return false
+}
diff --git a/src/strconv/eisel_lemire.go b/src/strconv/eisel_lemire.go
index 6c7f852eba8..fecd1b93451 100644
--- a/src/strconv/eisel_lemire.go
+++ b/src/strconv/eisel_lemire.go
@@ -29,7 +29,7 @@ func eiselLemire64(man uint64, exp10 int, neg bool) (f float64, ok bool) {
 	// Exp10 Range.
 	if man == 0 {
 		if neg {
-			f = math.Float64frombits(0x80000000_00000000) // Negative zero.
+			f = math.Float64frombits(0x8000000000000000) // Negative zero.
 		}
 		return f, true
 	}
@@ -39,7 +39,7 @@ func eiselLemire64(man uint64, exp10 int, neg bool) (f float64, ok bool) {
 
 	// Normalization.
 	clz := bits.LeadingZeros64(man)
-	man <<= clz
+	man <<= uint(clz)
 	const float64ExponentBias = 1023
 	retExp2 := uint64(217706*exp10>>16+64+float64ExponentBias) - uint64(clz)
 
@@ -84,9 +84,9 @@ func eiselLemire64(man uint64, exp10 int, neg bool) (f float64, ok bool) {
 	if retExp2-1 >= 0x7FF-1 {
 		return 0, false
 	}
-	retBits := retExp2<<52 | retMantissa&0x000FFFFF_FFFFFFFF
+	retBits := retExp2<<52 | retMantissa&0x000FFFFFFFFFFFFF
 	if neg {
-		retBits |= 0x80000000_00000000
+		retBits |= 0x8000000000000000
 	}
 	return math.Float64frombits(retBits), true
 }
@@ -114,7 +114,7 @@ func eiselLemire32(man uint64, exp10 int, neg bool) (f float32, ok bool) {
 
 	// Normalization.
 	clz := bits.LeadingZeros64(man)
-	man <<= clz
+	man <<= uint(clz)
 	const float32ExponentBias = 127
 	retExp2 := uint64(217706*exp10>>16+64+float32ExponentBias) - uint64(clz)
 
@@ -122,13 +122,13 @@ func eiselLemire32(man uint64, exp10 int, neg bool) (f float32, ok bool) {
 	xHi, xLo := bits.Mul64(man, detailedPowersOfTen[exp10-detailedPowersOfTenMinExp10][1])
 
 	// Wider Approximation.
-	if xHi&0x3F_FFFFFFFF == 0x3F_FFFFFFFF && xLo+man < man {
+	if xHi&0x3FFFFFFFFF == 0x3FFFFFFFFF && xLo+man < man {
 		yHi, yLo := bits.Mul64(man, detailedPowersOfTen[exp10-detailedPowersOfTenMinExp10][0])
 		mergedHi, mergedLo := xHi, xLo+yHi
 		if mergedLo < xLo {
 			mergedHi++
 		}
-		if mergedHi&0x3F_FFFFFFFF == 0x3F_FFFFFFFF && mergedLo+1 == 0 && yLo+man < man {
+		if mergedHi&0x3FFFFFFFFF == 0x3FFFFFFFFF && mergedLo+1 == 0 && yLo+man < man {
 			return 0, false
 		}
 		xHi, xLo = mergedHi, mergedLo
@@ -140,7 +140,7 @@ func eiselLemire32(man uint64, exp10 int, neg bool) (f float32, ok bool) {
 	retExp2 -= 1 ^ msb
 
 	// Half-way Ambiguity.
-	if xLo == 0 && xHi&0x3F_FFFFFFFF == 0 && retMantissa&3 == 1 {
+	if xLo == 0 && xHi&0x3FFFFFFFFF == 0 && retMantissa&3 == 1 {
 		return 0, false
 	}
 
diff --git a/src/strconv/quote.go b/src/strconv/quote.go
index bcbdbc514d2..4ffa10b72ef 100644
--- a/src/strconv/quote.go
+++ b/src/strconv/quote.go
@@ -7,7 +7,6 @@
 package strconv
 
 import (
-	"internal/bytealg"
 	"unicode/utf8"
 )
 
@@ -436,11 +435,6 @@ func Unquote(s string) (string, error) {
 	return string(buf), nil
 }
 
-// contains reports whether the string contains the byte c.
-func contains(s string, c byte) bool {
-	return bytealg.IndexByteString(s, c) != -1
-}
-
 // bsearch16 returns the smallest i such that a[i] >= x.
 // If there is no such i, bsearch16 returns len(a).
 func bsearch16(a []uint16, x uint16) int {