diff --git a/src/cmd/go.mod b/src/cmd/go.mod
index 6d57cee..21670b9 100644
--- a/src/cmd/go.mod
+++ b/src/cmd/go.mod
@@ -7,7 +7,7 @@
 	github.com/ianlancetaylor/demangle v0.0.0-20200414190113-039b1ae3a340 // indirect
 	golang.org/x/arch v0.0.0-20200511175325-f7c78586839d
 	golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9
-	golang.org/x/mod v0.3.0
+	golang.org/x/mod v0.3.1-0.20200625141748-0b26df4a2231
 	golang.org/x/sys v0.0.0-20200501145240-bc7a7d42d5c3 // indirect
 	golang.org/x/tools v0.0.0-20200616133436-c1934b75d054
 	golang.org/x/xerrors v0.0.0-20200806184451-1a77d5e9f316 // indirect
diff --git a/src/cmd/go.sum b/src/cmd/go.sum
index 3fc693e..1b5ef51 100644
--- a/src/cmd/go.sum
+++ b/src/cmd/go.sum
@@ -14,8 +14,8 @@
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9 h1:psW17arqaxU48Z5kZ0CQnkZWQJsqcURM6tKiBApRjXI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
-golang.org/x/mod v0.3.0 h1:RM4zey1++hCTbCVQfnWeKs9/IEsaBLA8vTkd0WVtmH4=
-golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
+golang.org/x/mod v0.3.1-0.20200625141748-0b26df4a2231 h1:R11LxkoUvECaAHdM5/ZOevSR7n+016EgTw8nbE1l+XM=
+golang.org/x/mod v0.3.1-0.20200625141748-0b26df4a2231/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
diff --git a/src/cmd/go/internal/modfetch/insecure.go b/src/cmd/go/internal/modfetch/insecure.go
index 8420432..b692669 100644
--- a/src/cmd/go/internal/modfetch/insecure.go
+++ b/src/cmd/go/internal/modfetch/insecure.go
@@ -7,10 +7,11 @@
 import (
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/get"
-	"cmd/go/internal/str"
+
+	"golang.org/x/mod/module"
 )
 
 // allowInsecure reports whether we are allowed to fetch this path in an insecure manner.
 func allowInsecure(path string) bool {
-	return get.Insecure || str.GlobsMatchPath(cfg.GOINSECURE, path)
+	return get.Insecure || module.MatchPrefixPatterns(cfg.GOINSECURE, path)
 }
diff --git a/src/cmd/go/internal/modfetch/repo.go b/src/cmd/go/internal/modfetch/repo.go
index f03bdd8..34f805d 100644
--- a/src/cmd/go/internal/modfetch/repo.go
+++ b/src/cmd/go/internal/modfetch/repo.go
@@ -16,9 +16,9 @@
 	"cmd/go/internal/get"
 	"cmd/go/internal/modfetch/codehost"
 	"cmd/go/internal/par"
-	"cmd/go/internal/str"
 	web "cmd/go/internal/web"
 
+	"golang.org/x/mod/module"
 	"golang.org/x/mod/semver"
 )
 
@@ -217,7 +217,7 @@
 		return nil, errLookupDisabled
 	}
 
-	if str.GlobsMatchPath(cfg.GONOPROXY, path) {
+	if module.MatchPrefixPatterns(cfg.GONOPROXY, path) {
 		switch proxy {
 		case "noproxy", "direct":
 			return lookupDirect(path)
diff --git a/src/cmd/go/internal/modfetch/sumdb.go b/src/cmd/go/internal/modfetch/sumdb.go
index 7973f47..783c4a4 100644
--- a/src/cmd/go/internal/modfetch/sumdb.go
+++ b/src/cmd/go/internal/modfetch/sumdb.go
@@ -24,7 +24,6 @@
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/get"
 	"cmd/go/internal/lockedfile"
-	"cmd/go/internal/str"
 	"cmd/go/internal/web"
 
 	"golang.org/x/mod/module"
@@ -34,7 +33,7 @@
 
 // useSumDB reports whether to use the Go checksum database for the given module.
 func useSumDB(mod module.Version) bool {
-	return cfg.GOSUMDB != "off" && !get.Insecure && !str.GlobsMatchPath(cfg.GONOSUMDB, mod.Path)
+	return cfg.GOSUMDB != "off" && !get.Insecure && !module.MatchPrefixPatterns(cfg.GONOSUMDB, mod.Path)
 }
 
 // lookupSumDB returns the Go checksum database's go.sum lines for the given module,
diff --git a/src/cmd/go/internal/str/path.go b/src/cmd/go/internal/str/path.go
index 95d91a3..51ab2af 100644
--- a/src/cmd/go/internal/str/path.go
+++ b/src/cmd/go/internal/str/path.go
@@ -5,7 +5,6 @@
 package str
 
 import (
-	"path"
 	"path/filepath"
 	"strings"
 )
@@ -50,47 +49,3 @@
 		return s[len(prefix)] == filepath.Separator && s[:len(prefix)] == prefix
 	}
 }
-
-// GlobsMatchPath reports whether any path prefix of target
-// matches one of the glob patterns (as defined by path.Match)
-// in the comma-separated globs list.
-// It ignores any empty or malformed patterns in the list.
-func GlobsMatchPath(globs, target string) bool {
-	for globs != "" {
-		// Extract next non-empty glob in comma-separated list.
-		var glob string
-		if i := strings.Index(globs, ","); i >= 0 {
-			glob, globs = globs[:i], globs[i+1:]
-		} else {
-			glob, globs = globs, ""
-		}
-		if glob == "" {
-			continue
-		}
-
-		// A glob with N+1 path elements (N slashes) needs to be matched
-		// against the first N+1 path elements of target,
-		// which end just before the N+1'th slash.
-		n := strings.Count(glob, "/")
-		prefix := target
-		// Walk target, counting slashes, truncating at the N+1'th slash.
-		for i := 0; i < len(target); i++ {
-			if target[i] == '/' {
-				if n == 0 {
-					prefix = target[:i]
-					break
-				}
-				n--
-			}
-		}
-		if n > 0 {
-			// Not enough prefix elements.
-			continue
-		}
-		matched, _ := path.Match(glob, prefix)
-		if matched {
-			return true
-		}
-	}
-	return false
-}
diff --git a/src/cmd/vendor/golang.org/x/mod/module/module.go b/src/cmd/vendor/golang.org/x/mod/module/module.go
index 6cd3728..3a8b080 100644
--- a/src/cmd/vendor/golang.org/x/mod/module/module.go
+++ b/src/cmd/vendor/golang.org/x/mod/module/module.go
@@ -97,6 +97,7 @@
 
 import (
 	"fmt"
+	"path"
 	"sort"
 	"strings"
 	"unicode"
@@ -716,3 +717,49 @@
 	}
 	return string(buf), true
 }
+
+// MatchPrefixPatterns reports whether any path prefix of target matches one of
+// the glob patterns (as defined by path.Match) in the comma-separated globs
+// list. This implements the algorithm used when matching a module path to the
+// GOPRIVATE environment variable, as described by 'go help module-private'.
+//
+// It ignores any empty or malformed patterns in the list.
+func MatchPrefixPatterns(globs, target string) bool {
+	for globs != "" {
+		// Extract next non-empty glob in comma-separated list.
+		var glob string
+		if i := strings.Index(globs, ","); i >= 0 {
+			glob, globs = globs[:i], globs[i+1:]
+		} else {
+			glob, globs = globs, ""
+		}
+		if glob == "" {
+			continue
+		}
+
+		// A glob with N+1 path elements (N slashes) needs to be matched
+		// against the first N+1 path elements of target,
+		// which end just before the N+1'th slash.
+		n := strings.Count(glob, "/")
+		prefix := target
+		// Walk target, counting slashes, truncating at the N+1'th slash.
+		for i := 0; i < len(target); i++ {
+			if target[i] == '/' {
+				if n == 0 {
+					prefix = target[:i]
+					break
+				}
+				n--
+			}
+		}
+		if n > 0 {
+			// Not enough prefix elements.
+			continue
+		}
+		matched, _ := path.Match(glob, prefix)
+		if matched {
+			return true
+		}
+	}
+	return false
+}
diff --git a/src/cmd/vendor/modules.txt b/src/cmd/vendor/modules.txt
index 21fc78c..7272f04 100644
--- a/src/cmd/vendor/modules.txt
+++ b/src/cmd/vendor/modules.txt
@@ -29,7 +29,7 @@
 golang.org/x/crypto/ed25519
 golang.org/x/crypto/ed25519/internal/edwards25519
 golang.org/x/crypto/ssh/terminal
-# golang.org/x/mod v0.3.0
+# golang.org/x/mod v0.3.1-0.20200625141748-0b26df4a2231
 ## explicit
 golang.org/x/mod/internal/lazyregexp
 golang.org/x/mod/modfile