diff --git a/expand/expand.go b/expand/expand.go
index 7b225180..996d496f 100644
--- a/expand/expand.go
+++ b/expand/expand.go
@@ -287,9 +287,10 @@ formatLoop:
 			case 'x', 'u', 'U':
 				i++
 				max := 2
-				if c == 'u' {
+				switch c {
+				case 'u':
 					max = 4
-				} else if c == 'U' {
+				case 'U':
 					max = 8
 				}
 				digits := readDigits(max, true)
diff --git a/expand/param.go b/expand/param.go
index bf0d2382..1f1a475f 100644
--- a/expand/param.go
+++ b/expand/param.go
@@ -199,8 +199,7 @@ func (cfg *Config) paramExp(pe *syntax.ParamExp) (string, error) {
 			if pe.Slice.Length != nil {
 				str = str[:slicePos(sliceLen)]
 			}
-		} else { // elems are already sliced
-		}
+		} // else, elems are already sliced
 	case pe.Repl != nil:
 		orig, err := Pattern(cfg, pe.Repl.Orig)
 		if err != nil {
diff --git a/interp/os_unix.go b/interp/os_unix.go
index 1a14e465..e393399c 100644
--- a/interp/os_unix.go
+++ b/interp/os_unix.go
@@ -27,6 +27,7 @@ func hasPermissionToDir(info os.FileInfo) bool {
 	}
 	uid, err := strconv.Atoi(user.Uid)
 	if err != nil {
+		return false // on POSIX systems, Uid should always be a decimal number
 	}
 	if uid == 0 {
 		return true // super-user
diff --git a/syntax/lexer.go b/syntax/lexer.go
index 583abb61..6e9aef44 100644
--- a/syntax/lexer.go
+++ b/syntax/lexer.go
@@ -372,10 +372,7 @@ func (p *Parser) extendedGlob() bool {
 		// We do this after peeking for just one byte, so that the input `echo *`
 		// followed by a newline does not hang an interactive shell parser until
 		// another byte is input.
-		if p.peekBytes("()") {
-			return false
-		}
-		return true
+		return !p.peekBytes("()")
 	}
 	return false
 }
diff --git a/syntax/parser.go b/syntax/parser.go
index 048a919c..feeae949 100644
--- a/syntax/parser.go
+++ b/syntax/parser.go
@@ -2077,7 +2077,7 @@ func (p *Parser) caseClause(s *Stmt) {
 
 func (p *Parser) caseItems(stop string) (items []*CaseItem) {
 	p.got(_Newl)
-	for p.tok != _EOF && !(p.tok == _LitWord && p.val == stop) {
+	for p.tok != _EOF && (p.tok != _LitWord || p.val != stop) {
 		ci := &CaseItem{}
 		ci.Comments, p.accComs = p.accComs, nil
 		p.got(leftParen)