switch staticcheck for megacheck and fix things it complains about

Makefile

@@ -1,12 +1,14 @@
 BUMP_VERSION := $(shell command -v bump_version)
-STATICCHECK := $(shell command -v staticcheck)
+MEGACHECK := $(shell command -v megaccheck)
+
+IGNORES := 'github.com/kevinburke/ssh_config/config.go:U1000 github.com/kevinburke/ssh_config/config.go:S1002 github.com/kevinburke/ssh_config/token.go:U1000'
 
 lint:
 	go vet ./...
-ifndef STATICCHECK
-	go get -u honnef.co/go/tools/cmd/staticcheck
+ifndef MEGACHECK
+	go get -u honnef.co/go/tools/cmd/megacheck
 endif
-	staticcheck ./...
+	megacheck --ignore=$(IGNORES) ./...
 
 test: lint
 	@# the timeout helps guard against infinite recursion

config.go

@@ -55,7 +55,6 @@ type UserSettings struct {
 	systemConfigFinder configFinder
 	userConfig         *Config
 	userConfigFinder   configFinder
-	username           string
 	loadConfigs        sync.Once
 	onceErr            error
 }

config_test.go

@@ -293,7 +293,7 @@ var matchTests = []struct {
 
 func TestMatches(t *testing.T) {
 	for _, tt := range matchTests {
-		patterns := make([]*Pattern, len(tt.in), len(tt.in))
+		patterns := make([]*Pattern, len(tt.in))
 		for i := range tt.in {
 			pat, err := NewPattern(tt.in[i])
 			if err != nil {

lexer.go

@@ -13,7 +13,6 @@ type sshLexer struct {
 	input         *buffruneio.Reader // Textual source
 	buffer        []rune             // Runes composing the current token
 	tokens        chan token
-	depth         int
 	line          uint32
 	col           uint16
 	endbufferLine uint32

parser.go

@@ -167,17 +167,6 @@ func (p *sshParser) parseComment() sshParserStateFn {
 	return p.parseStart
 }
 
-// assume peeks at the next token and ensures it's the right type
-func (p *sshParser) assume(typ tokenType) {
-	tok := p.peek()
-	if tok == nil {
-		p.raiseErrorf(tok, "was expecting token %s, but token stream is empty", tok)
-	}
-	if tok.typ != typ {
-		p.raiseErrorf(tok, "was expecting token %s, but got %s instead", typ, tok)
-	}
-}
-
 func parseSSH(flow chan token, system bool, depth uint8) *Config {
 	result := newConfig()
 	result.position = Position{1, 1}