diff --git a/fuzz/fuzz.go b/fuzz/fuzz.go
index f56dec6..629f5cc 100644
--- a/fuzz/fuzz.go
+++ b/fuzz/fuzz.go
@@ -2,11 +2,13 @@ package fuzz
 
 import (
 	"bytes"
+
 	"github.com/yuin/goldmark"
 	"github.com/yuin/goldmark/extension"
 	"github.com/yuin/goldmark/renderer/html"
 )
 
+// Fuzz runs automated fuzzing against goldmark.
 func Fuzz(data []byte) int {
 	markdown := goldmark.New(
 		goldmark.WithRendererOptions(
diff --git a/parser/html_block.go b/parser/html_block.go
index 752ba08..c796354 100644
--- a/parser/html_block.go
+++ b/parser/html_block.go
@@ -2,11 +2,12 @@ package parser
 
 import (
 	"bytes"
+	"regexp"
+	"strings"
+
 	"github.com/yuin/goldmark/ast"
 	"github.com/yuin/goldmark/text"
 	"github.com/yuin/goldmark/util"
-	"regexp"
-	"strings"
 )
 
 var allowedBlockTags = map[string]bool{
@@ -97,12 +98,12 @@ var htmlBlockType7Regexp = regexp.MustCompile(`^[ ]{0,3}<(/)?([a-zA-Z0-9]+)(` +
 type htmlBlockParser struct {
 }
 
-var defaultHtmlBlockParser = &htmlBlockParser{}
+var defaultHTMLBlockParser = &htmlBlockParser{}
 
 // NewHTMLBlockParser return a new BlockParser that can parse html
 // blocks.
 func NewHTMLBlockParser() BlockParser {
-	return defaultHtmlBlockParser
+	return defaultHTMLBlockParser
 }
 
 func (b *htmlBlockParser) Trigger() []byte {
diff --git a/parser/thematic_break.go b/parser/thematic_break.go
index 2f5c9fa..4d0d8da 100644
--- a/parser/thematic_break.go
+++ b/parser/thematic_break.go
@@ -11,7 +11,7 @@ type thematicBreakPraser struct {
 
 var defaultThematicBreakPraser = &thematicBreakPraser{}
 
-// NewThematicBreakPraser returns a new BlockParser that
+// NewThematicBreakParser returns a new BlockParser that
 // parses thematic breaks.
 func NewThematicBreakParser() BlockParser {
 	return defaultThematicBreakPraser
diff --git a/renderer/renderer.go b/renderer/renderer.go
index 1681305..5c11ceb 100644
--- a/renderer/renderer.go
+++ b/renderer/renderer.go
@@ -1,14 +1,13 @@
-// Package renderer	renders the given AST to certain formats.
+// Package renderer renders the given AST to certain formats.
 package renderer
 
 import (
 	"bufio"
 	"io"
+	"sync"
 
 	"github.com/yuin/goldmark/ast"
 	"github.com/yuin/goldmark/util"
-
-	"sync"
 )
 
 // A Config struct is a data structure that holds configuration of the Renderer.
diff --git a/testutil/testutil.go b/testutil/testutil.go
index 4a83a03..4b9cff6 100644
--- a/testutil/testutil.go
+++ b/testutil/testutil.go
@@ -21,6 +21,7 @@ type TestingT interface {
 	FailNow()
 }
 
+// MarkdownTestCase represents a test case.
 type MarkdownTestCase struct {
 	No       int
 	Markdown string
@@ -30,6 +31,7 @@ type MarkdownTestCase struct {
 const attributeSeparator = "//- - - - - - - - -//"
 const caseSeparator = "//= = = = = = = = = = = = = = = = = = = = = = = =//"
 
+// DoTestCaseFile runs test cases in a given file.
 func DoTestCaseFile(m goldmark.Markdown, filename string, t TestingT) {
 	fp, err := os.Open(filename)
 	if err != nil {
@@ -86,12 +88,14 @@ func DoTestCaseFile(m goldmark.Markdown, filename string, t TestingT) {
 	DoTestCases(m, cases, t)
 }
 
+// DoTestCases runs a set of test cases.
 func DoTestCases(m goldmark.Markdown, cases []MarkdownTestCase, t TestingT) {
 	for _, testCase := range cases {
 		DoTestCase(m, testCase, t)
 	}
 }
 
+// DoTestCase runs a test case.
 func DoTestCase(m goldmark.Markdown, testCase MarkdownTestCase, t TestingT) {
 	var ok bool
 	var out bytes.Buffer
diff --git a/text/reader.go b/text/reader.go
index 0e2c3f0..a8db23b 100644
--- a/text/reader.go
+++ b/text/reader.go
@@ -1,10 +1,11 @@
 package text
 
 import (
-	"github.com/yuin/goldmark/util"
 	"io"
 	"regexp"
 	"unicode/utf8"
+
+	"github.com/yuin/goldmark/util"
 )
 
 const invalidValue = -1
@@ -138,7 +139,7 @@ func (r *reader) LineOffset() int {
 			if r.source[i] == '\t' {
 				v += util.TabWidth(v)
 			} else {
-				v += 1
+				v++
 			}
 		}
 		r.lineOffset = v - r.pos.Padding
@@ -355,7 +356,7 @@ func (r *blockReader) LineOffset() int {
 			if r.source[i] == '\t' {
 				v += util.TabWidth(v)
 			} else {
-				v += 1
+				v++
 			}
 		}
 		r.lineOffset = v - r.pos.Padding
diff --git a/util/util.go b/util/util.go
index 57a2b84..74f991b 100644
--- a/util/util.go
+++ b/util/util.go
@@ -631,7 +631,7 @@ func URLEscape(v []byte, resolveReference bool) []byte {
 		cob.Write(v[n:i])
 		stop := i + int(u8len)
 		if stop > len(v) {
-			i += 1
+			i++
 			n = i
 			continue
 		}