diff --git a/encoding/prototext/decode.go b/encoding/prototext/decode.go
index 5e9975d..9dea257 100644
--- a/encoding/prototext/decode.go
+++ b/encoding/prototext/decode.go
@@ -6,7 +6,6 @@
 
 import (
 	"fmt"
-	"io"
 	"strings"
 	"unicode/utf8"
 
@@ -131,7 +130,7 @@
 			// Continue below.
 		case text.EOF:
 			if checkDelims {
-				return io.ErrUnexpectedEOF
+				return text.ErrUnexpectedEOF
 			}
 			return nil
 		default:
diff --git a/internal/encoding/text/decode.go b/internal/encoding/text/decode.go
index 074e849..eb10ea1 100644
--- a/internal/encoding/text/decode.go
+++ b/internal/encoding/text/decode.go
@@ -45,6 +45,9 @@
 	return &Decoder{orig: b, in: b}
 }
 
+// ErrUnexpectedEOF means that EOF was encountered in the middle of the input.
+var ErrUnexpectedEOF = errors.New("%v", io.ErrUnexpectedEOF)
+
 // call specifies which Decoder method was invoked.
 type call uint8
 
@@ -70,7 +73,7 @@
 		return d.lastToken, d.lastErr
 	}
 
-	tok, err := d.parseNext(d.lastToken.Kind())
+	tok, err := d.parseNext(d.lastToken.kind)
 	if err != nil {
 		return Token{}, err
 	}
@@ -114,7 +117,7 @@
 	case Name:
 		// Next token can be MessageOpen, ListOpen or Scalar.
 		if isEOF {
-			return Token{}, io.ErrUnexpectedEOF
+			return Token{}, ErrUnexpectedEOF
 		}
 		switch ch := d.in[0]; ch {
 		case '{', '<':
@@ -148,7 +151,7 @@
 		case MessageOpen:
 			// Next token can be MessageClose, comma, semicolon or Name.
 			if isEOF {
-				return Token{}, io.ErrUnexpectedEOF
+				return Token{}, ErrUnexpectedEOF
 			}
 			switch ch := d.in[0]; ch {
 			case closeCh:
@@ -167,7 +170,7 @@
 		case ListOpen:
 			// Next token can be ListClose or comma.
 			if isEOF {
-				return Token{}, io.ErrUnexpectedEOF
+				return Token{}, ErrUnexpectedEOF
 			}
 			switch ch := d.in[0]; ch {
 			case ']':
@@ -183,7 +186,7 @@
 	case MessageOpen:
 		// Next token can be MessageClose or Name.
 		if isEOF {
-			return Token{}, io.ErrUnexpectedEOF
+			return Token{}, ErrUnexpectedEOF
 		}
 		_, closeCh := d.currentOpenKind()
 		switch ch := d.in[0]; ch {
@@ -217,7 +220,7 @@
 		case MessageOpen:
 			// Next token can be MessageClose, comma, semicolon or Name.
 			if isEOF {
-				return Token{}, io.ErrUnexpectedEOF
+				return Token{}, ErrUnexpectedEOF
 			}
 			switch ch := d.in[0]; ch {
 			case closeCh:
@@ -236,7 +239,7 @@
 		case ListOpen:
 			// Next token can be ListClose or comma
 			if isEOF {
-				return Token{}, io.ErrUnexpectedEOF
+				return Token{}, ErrUnexpectedEOF
 			}
 			switch ch := d.in[0]; ch {
 			case closeCh:
@@ -252,7 +255,7 @@
 	case ListOpen:
 		// Next token can be ListClose, MessageStart or Scalar.
 		if isEOF {
-			return Token{}, io.ErrUnexpectedEOF
+			return Token{}, ErrUnexpectedEOF
 		}
 		switch ch := d.in[0]; ch {
 		case ']':
@@ -286,7 +289,7 @@
 		case MessageOpen:
 			// Next token can be MessageClose, comma, semicolon or Name.
 			if isEOF {
-				return Token{}, io.ErrUnexpectedEOF
+				return Token{}, ErrUnexpectedEOF
 			}
 			switch ch := d.in[0]; ch {
 			case closeCh:
@@ -319,7 +322,7 @@
 		case MessageOpen:
 			// Next token can be MessageClose or Name.
 			if isEOF {
-				return Token{}, io.ErrUnexpectedEOF
+				return Token{}, ErrUnexpectedEOF
 			}
 			switch ch := d.in[0]; ch {
 			case closeCh:
@@ -340,7 +343,7 @@
 			}
 			// Next token can be MessageOpen or Scalar.
 			if isEOF {
-				return Token{}, io.ErrUnexpectedEOF
+				return Token{}, ErrUnexpectedEOF
 			}
 			switch ch := d.in[0]; ch {
 			case '{', '<':
@@ -432,7 +435,7 @@
 	// Caller already checks for [ as first character.
 	s := consume(d.in[1:], 0)
 	if len(s) == 0 {
-		return Token{}, io.ErrUnexpectedEOF
+		return Token{}, ErrUnexpectedEOF
 	}
 
 	var name []byte
@@ -470,7 +473,7 @@
 	}
 
 	if !closed {
-		return Token{}, io.ErrUnexpectedEOF
+		return Token{}, ErrUnexpectedEOF
 	}
 
 	// First character cannot be '.'. Last character cannot be '.' or '/'.
diff --git a/internal/encoding/text/decode_string.go b/internal/encoding/text/decode_string.go
index 020c8c7..d4d3490 100644
--- a/internal/encoding/text/decode_string.go
+++ b/internal/encoding/text/decode_string.go
@@ -6,7 +6,6 @@
 
 import (
 	"bytes"
-	"io"
 	"strconv"
 	"strings"
 	"unicode"
@@ -51,7 +50,7 @@
 func (d *Decoder) parseString() (string, error) {
 	in := d.in
 	if len(in) == 0 {
-		return "", io.ErrUnexpectedEOF
+		return "", ErrUnexpectedEOF
 	}
 	quote := in[0]
 	in = in[1:]
@@ -69,7 +68,7 @@
 			return string(out), nil
 		case r == '\\':
 			if len(in) < 2 {
-				return "", io.ErrUnexpectedEOF
+				return "", ErrUnexpectedEOF
 			}
 			switch r := in[1]; r {
 			case '"', '\'', '\\', '?':
@@ -117,7 +116,7 @@
 					n = 10
 				}
 				if len(in) < n {
-					return "", io.ErrUnexpectedEOF
+					return "", ErrUnexpectedEOF
 				}
 				v, err := strconv.ParseUint(string(in[2:n]), 16, 32)
 				if utf8.MaxRune < v || err != nil {
@@ -128,7 +127,7 @@
 				r := rune(v)
 				if utf16.IsSurrogate(r) {
 					if len(in) < 6 {
-						return "", io.ErrUnexpectedEOF
+						return "", ErrUnexpectedEOF
 					}
 					v, err := strconv.ParseUint(string(in[2:6]), 16, 16)
 					r = utf16.DecodeRune(r, rune(v))
@@ -146,7 +145,7 @@
 			in, out = in[n+i:], append(out, in[:n+i]...)
 		}
 	}
-	return "", io.ErrUnexpectedEOF
+	return "", ErrUnexpectedEOF
 }
 
 // indexNeedEscapeInString returns the index of the character that needs
diff --git a/internal/encoding/text/decode_test.go b/internal/encoding/text/decode_test.go
index 6ad31ce..4749f8c 100644
--- a/internal/encoding/text/decode_test.go
+++ b/internal/encoding/text/decode_test.go
@@ -6,7 +6,6 @@
 
 import (
 	"fmt"
-	"io"
 	"math"
 	"strings"
 	"testing"
@@ -17,7 +16,7 @@
 	"google.golang.org/protobuf/internal/flags"
 )
 
-var eofErr = io.ErrUnexpectedEOF.Error()
+var eofErr = text.ErrUnexpectedEOF.Error()
 
 type R struct {
 	// K is expected Kind of the returned Token object from calling Decoder.Read.
diff --git a/internal/encoding/text/decode_token.go b/internal/encoding/text/decode_token.go
index b7b4e2f..83d2b0d 100644
--- a/internal/encoding/text/decode_token.go
+++ b/internal/encoding/text/decode_token.go
@@ -1,6 +1,7 @@
 // Copyright 2018 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.
+
 package text
 
 import (
@@ -16,6 +17,7 @@
 // Kind represents a token kind expressible in the textproto format.
 type Kind uint8
 
+// Kind values.
 const (
 	Invalid Kind = iota
 	EOF
@@ -65,6 +67,7 @@
 // NameKind represents different types of field names.
 type NameKind uint8
 
+// NameKind values.
 const (
 	IdentName NameKind = iota + 1
 	TypeName
diff --git a/internal/encoding/text/encode.go b/internal/encoding/text/encode.go
index a593978..c4ba1c5 100644
--- a/internal/encoding/text/encode.go
+++ b/internal/encoding/text/encode.go
@@ -93,7 +93,7 @@
 	e.out = append(e.out, e.delims[1])
 }
 
-// Writname writes out the field name and the separator ':'.
+// WriteName writes out the field name and the separator ':'.
 func (e *Encoder) WriteName(s string) {
 	e.prepareNext(name)
 	e.out = append(e.out, s...)