diff --git a/Makefile b/Makefile
index f85c21200..08d6c4d68 100644
--- a/Makefile
+++ b/Makefile
@@ -15,5 +15,5 @@ build:
 	@go build -ldflags='$(VERSION_FLAGS)'
 
 test:
-	@go test -v ./...
+	@go test -v -race ./...
 
diff --git a/lint/file.go b/lint/file.go
index 6505760f5..af4bc16ae 100644
--- a/lint/file.go
+++ b/lint/file.go
@@ -78,7 +78,7 @@ func (f *File) IsUntypedConst(expr ast.Expr) (defType string, ok bool) {
 	// Re-evaluate expr outside its context to see if it's untyped.
 	// (An expr evaluated within, for example, an assignment context will get the type of the LHS.)
 	exprStr := f.Render(expr)
-	tv, err := types.Eval(f.Pkg.fset, f.Pkg.TypesPkg, expr.Pos(), exprStr)
+	tv, err := types.Eval(f.Pkg.fset, f.Pkg.TypesPkg(), expr.Pos(), exprStr)
 	if err != nil {
 		return "", false
 	}
diff --git a/lint/linter.go b/lint/linter.go
index 940c858b0..a88425bef 100644
--- a/lint/linter.go
+++ b/lint/linter.go
@@ -85,7 +85,6 @@ func (l *Linter) lintPackage(filenames []string, ruleSet []Rule, config Config,
 	pkg := &Package{
 		fset:  token.NewFileSet(),
 		files: map[string]*File{},
-		mu:    sync.Mutex{},
 	}
 	for _, filename := range filenames {
 		content, err := l.readFile(filename)
diff --git a/lint/package.go b/lint/package.go
index fd858c56a..eb5c112f8 100644
--- a/lint/package.go
+++ b/lint/package.go
@@ -16,14 +16,14 @@ type Package struct {
 	fset  *token.FileSet
 	files map[string]*File
 
-	TypesPkg  *types.Package
-	TypesInfo *types.Info
+	typesPkg  *types.Package
+	typesInfo *types.Info
 
 	// sortable is the set of types in the package that implement sort.Interface.
-	Sortable map[string]bool
+	sortable map[string]bool
 	// main is whether this is a "main" package.
 	main int
-	mu   sync.Mutex
+	sync.RWMutex
 }
 
 var newImporter = func(fset *token.FileSet) types.ImporterFrom {
@@ -38,6 +38,9 @@ var (
 
 // IsMain returns if that's the main package.
 func (p *Package) IsMain() bool {
+	p.Lock()
+	defer p.Unlock()
+
 	if p.main == trueValue {
 		return true
 	} else if p.main == falseValue {
@@ -53,13 +56,35 @@ func (p *Package) IsMain() bool {
 	return false
 }
 
+// TypesPkg yields information on this package
+func (p *Package) TypesPkg() *types.Package {
+	p.RLock()
+	defer p.RUnlock()
+	return p.typesPkg
+}
+
+// TypesInfo yields type information of this package identifiers
+func (p *Package) TypesInfo() *types.Info {
+	p.RLock()
+	defer p.RUnlock()
+	return p.typesInfo
+}
+
+// Sortable yields a map of sortable types in this package
+func (p *Package) Sortable() map[string]bool {
+	p.RLock()
+	defer p.RUnlock()
+	return p.sortable
+}
+
 // TypeCheck performs type checking for given package.
 func (p *Package) TypeCheck() error {
-	p.mu.Lock()
+	p.Lock()
+	defer p.Unlock()
+
 	// If type checking has already been performed
 	// skip it.
-	if p.TypesInfo != nil || p.TypesPkg != nil {
-		p.mu.Unlock()
+	if p.typesInfo != nil || p.typesPkg != nil {
 		return nil
 	}
 	config := &types.Config{
@@ -84,9 +109,9 @@ func (p *Package) TypeCheck() error {
 
 	// Remember the typechecking info, even if config.Check failed,
 	// since we will get partial information.
-	p.TypesPkg = typesPkg
-	p.TypesInfo = info
-	p.mu.Unlock()
+	p.typesPkg = typesPkg
+	p.typesInfo = info
+
 	return err
 }
 
@@ -106,10 +131,10 @@ func check(config *types.Config, n string, fset *token.FileSet, astFiles []*ast.
 
 // TypeOf returns the type of an expression.
 func (p *Package) TypeOf(expr ast.Expr) types.Type {
-	if p.TypesInfo == nil {
+	if p.typesInfo == nil {
 		return nil
 	}
-	return p.TypesInfo.TypeOf(expr)
+	return p.typesInfo.TypeOf(expr)
 }
 
 type walker struct {
@@ -131,7 +156,7 @@ func (w *walker) Visit(n ast.Node) ast.Visitor {
 }
 
 func (p *Package) scanSortable() {
-	p.Sortable = make(map[string]bool)
+	p.sortable = make(map[string]bool)
 
 	// bitfield for which methods exist on each type.
 	const (
@@ -146,7 +171,7 @@ func (p *Package) scanSortable() {
 	}
 	for typ, ms := range has {
 		if ms == Len|Less|Swap {
-			p.Sortable[typ] = true
+			p.sortable[typ] = true
 		}
 	}
 }
diff --git a/rule/add-constant.go b/rule/add-constant.go
index f3f5f5662..f37dcc95e 100644
--- a/rule/add-constant.go
+++ b/rule/add-constant.go
@@ -5,6 +5,7 @@ import (
 	"go/ast"
 	"strconv"
 	"strings"
+	"sync"
 
 	"github.com/deepsourcelabs/revive/lint"
 )
@@ -33,53 +34,12 @@ func (wl whiteList) add(kind, list string) {
 type AddConstantRule struct {
 	whiteList   whiteList
 	strLitLimit int
+	sync.Mutex
 }
 
 // Apply applies the rule to given file.
 func (r *AddConstantRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
-	if r.whiteList == nil {
-		r.strLitLimit = defaultStrLitLimit
-		r.whiteList = newWhiteList()
-		if len(arguments) > 0 {
-			args, ok := arguments[0].(map[string]interface{})
-			if !ok {
-				panic(fmt.Sprintf("Invalid argument to the add-constant rule. Expecting a k,v map, got %T", arguments[0]))
-			}
-			for k, v := range args {
-				kind := ""
-				switch k {
-				case "allowFloats":
-					kind = kindFLOAT
-					fallthrough
-				case "allowInts":
-					if kind == "" {
-						kind = kindINT
-					}
-					fallthrough
-				case "allowStrs":
-					if kind == "" {
-						kind = kindSTRING
-					}
-					list, ok := v.(string)
-					if !ok {
-						panic(fmt.Sprintf("Invalid argument to the add-constant rule, string expected. Got '%v' (%T)", v, v))
-					}
-					r.whiteList.add(kind, list)
-				case "maxLitCount":
-					sl, ok := v.(string)
-					if !ok {
-						panic(fmt.Sprintf("Invalid argument to the add-constant rule, expecting string representation of an integer. Got '%v' (%T)", v, v))
-					}
-
-					limit, err := strconv.Atoi(sl)
-					if err != nil {
-						panic(fmt.Sprintf("Invalid argument to the add-constant rule, expecting string representation of an integer. Got '%v'", v))
-					}
-					r.strLitLimit = limit
-				}
-			}
-		}
-	}
+	r.configure(arguments)
 
 	var failures []lint.Failure
 
@@ -154,3 +114,52 @@ func (w lintAddConstantRule) checkNumLit(kind string, n *ast.BasicLit) {
 		Failure:    fmt.Sprintf("avoid magic numbers like '%s', create a named constant for it", n.Value),
 	})
 }
+
+func (r *AddConstantRule) configure(arguments lint.Arguments) {
+	r.Lock()
+	defer r.Unlock()
+
+	if r.whiteList == nil {
+		r.strLitLimit = defaultStrLitLimit
+		r.whiteList = newWhiteList()
+		if len(arguments) > 0 {
+			args, ok := arguments[0].(map[string]interface{})
+			if !ok {
+				panic(fmt.Sprintf("Invalid argument to the add-constant rule. Expecting a k,v map, got %T", arguments[0]))
+			}
+			for k, v := range args {
+				kind := ""
+				switch k {
+				case "allowFloats":
+					kind = kindFLOAT
+					fallthrough
+				case "allowInts":
+					if kind == "" {
+						kind = kindINT
+					}
+					fallthrough
+				case "allowStrs":
+					if kind == "" {
+						kind = kindSTRING
+					}
+					list, ok := v.(string)
+					if !ok {
+						panic(fmt.Sprintf("Invalid argument to the add-constant rule, string expected. Got '%v' (%T)", v, v))
+					}
+					r.whiteList.add(kind, list)
+				case "maxLitCount":
+					sl, ok := v.(string)
+					if !ok {
+						panic(fmt.Sprintf("Invalid argument to the add-constant rule, expecting string representation of an integer. Got '%v' (%T)", v, v))
+					}
+
+					limit, err := strconv.Atoi(sl)
+					if err != nil {
+						panic(fmt.Sprintf("Invalid argument to the add-constant rule, expecting string representation of an integer. Got '%v'", v))
+					}
+					r.strLitLimit = limit
+				}
+			}
+		}
+	}
+}
diff --git a/rule/argument-limit.go b/rule/argument-limit.go
index e3048111e..9a84ff5b8 100644
--- a/rule/argument-limit.go
+++ b/rule/argument-limit.go
@@ -3,6 +3,7 @@ package rule
 import (
 	"fmt"
 	"go/ast"
+	"sync"
 
 	"github.com/deepsourcelabs/revive/lint"
 )
@@ -10,10 +11,11 @@ import (
 // ArgumentsLimitRule lints given else constructs.
 type ArgumentsLimitRule struct {
 	total int
+	sync.Mutex
 }
 
-// Apply applies the rule to given file.
-func (r *ArgumentsLimitRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+func (r *ArgumentsLimitRule) configure(arguments lint.Arguments) {
+	r.Lock()
 	if r.total == 0 {
 		checkNumberOfArguments(1, arguments, r.Name())
 
@@ -23,14 +25,21 @@ func (r *ArgumentsLimitRule) Apply(file *lint.File, arguments lint.Arguments) []
 		}
 		r.total = int(total)
 	}
+	r.Unlock()
+}
+
+// Apply applies the rule to given file.
+func (r *ArgumentsLimitRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	r.configure(arguments)
 
 	var failures []lint.Failure
+	onFailure := func(failure lint.Failure) {
+		failures = append(failures, failure)
+	}
 
 	walker := lintArgsNum{
-		total: r.total,
-		onFailure: func(failure lint.Failure) {
-			failures = append(failures, failure)
-		},
+		total:     r.total,
+		onFailure: onFailure,
 	}
 
 	ast.Walk(walker, file.AST)
diff --git a/rule/atomic.go b/rule/atomic.go
index 7c6be3a47..c646cd6e2 100644
--- a/rule/atomic.go
+++ b/rule/atomic.go
@@ -15,7 +15,7 @@ type AtomicRule struct{}
 func (r *AtomicRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
 	var failures []lint.Failure
 	walker := atomic{
-		pkgTypesInfo: file.Pkg.TypesInfo,
+		pkgTypesInfo: file.Pkg.TypesInfo(),
 		onFailure: func(failure lint.Failure) {
 			failures = append(failures, failure)
 		},
diff --git a/rule/banned-characters.go b/rule/banned-characters.go
index 42238e528..b6ff956eb 100644
--- a/rule/banned-characters.go
+++ b/rule/banned-characters.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"go/ast"
 	"strings"
+	"sync"
 
 	"github.com/deepsourcelabs/revive/lint"
 )
@@ -11,16 +12,23 @@ import (
 // BannedCharsRule checks if a file contains banned characters.
 type BannedCharsRule struct {
 	bannedCharList []string
+	sync.Mutex
 }
 
 const bannedCharsRuleName = "banned-characters"
 
-// Apply applied the rule to the given file.
-func (r *BannedCharsRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+func (r *BannedCharsRule) configure(arguments lint.Arguments) {
+	r.Lock()
 	if r.bannedCharList == nil {
 		checkNumberOfArguments(1, arguments, bannedCharsRuleName)
 		r.bannedCharList = r.getBannedCharsList(arguments)
 	}
+	r.Unlock()
+}
+
+// Apply applied the rule to the given file.
+func (r *BannedCharsRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	r.configure(arguments)
 
 	var failures []lint.Failure
 	onFailure := func(failure lint.Failure) {
@@ -31,6 +39,7 @@ func (r *BannedCharsRule) Apply(file *lint.File, arguments lint.Arguments) []lin
 		bannedChars: r.bannedCharList,
 		onFailure:   onFailure,
 	}
+
 	ast.Walk(w, file.AST)
 	return failures
 }
diff --git a/rule/cognitive-complexity.go b/rule/cognitive-complexity.go
index 9ea5c11ed..b7cdd71f9 100644
--- a/rule/cognitive-complexity.go
+++ b/rule/cognitive-complexity.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"go/ast"
 	"go/token"
+	"sync"
 
 	"github.com/deepsourcelabs/revive/lint"
 	"golang.org/x/tools/go/ast/astutil"
@@ -12,10 +13,11 @@ import (
 // CognitiveComplexityRule lints given else constructs.
 type CognitiveComplexityRule struct {
 	maxComplexity int
+	sync.Mutex
 }
 
-// Apply applies the rule to given file.
-func (r *CognitiveComplexityRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+func (r *CognitiveComplexityRule) configure(arguments lint.Arguments) {
+	r.Lock()
 	if r.maxComplexity == 0 {
 		checkNumberOfArguments(1, arguments, r.Name())
 
@@ -25,8 +27,15 @@ func (r *CognitiveComplexityRule) Apply(file *lint.File, arguments lint.Argument
 		}
 		r.maxComplexity = int(complexity)
 	}
+	r.Unlock()
+}
+
+// Apply applies the rule to given file.
+func (r *CognitiveComplexityRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	r.configure(arguments)
 
 	var failures []lint.Failure
+
 	linter := cognitiveComplexityLinter{
 		file:          file,
 		maxComplexity: r.maxComplexity,
diff --git a/rule/context-as-argument.go b/rule/context-as-argument.go
index f062b095b..1798ee349 100644
--- a/rule/context-as-argument.go
+++ b/rule/context-as-argument.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"go/ast"
 	"strings"
+	"sync"
 
 	"github.com/deepsourcelabs/revive/lint"
 )
@@ -11,21 +12,27 @@ import (
 // ContextAsArgumentRule lints given else constructs.
 type ContextAsArgumentRule struct {
 	allowTypesLUT map[string]struct{}
+	sync.Mutex
 }
 
 // Apply applies the rule to given file.
 func (r *ContextAsArgumentRule) Apply(file *lint.File, args lint.Arguments) []lint.Failure {
+
+	r.Lock()
 	if r.allowTypesLUT == nil {
 		r.allowTypesLUT = getAllowTypesFromArguments(args)
 	}
+	r.Unlock()
 
 	var failures []lint.Failure
+	r.Lock()
 	walker := lintContextArguments{
 		allowTypesLUT: r.allowTypesLUT,
 		onFailure: func(failure lint.Failure) {
 			failures = append(failures, failure)
 		},
 	}
+	r.Unlock()
 
 	ast.Walk(walker, file.AST)
 
diff --git a/rule/context-keys-type.go b/rule/context-keys-type.go
index 9c933db7e..7ff58fc34 100644
--- a/rule/context-keys-type.go
+++ b/rule/context-keys-type.go
@@ -68,7 +68,7 @@ func checkContextKeyType(w lintContextKeyTypes, x *ast.CallExpr) {
 	if len(x.Args) != 3 {
 		return
 	}
-	key := f.Pkg.TypesInfo.Types[x.Args[1]]
+	key := f.Pkg.TypesInfo().Types[x.Args[1]]
 
 	if ktyp, ok := key.Type.(*types.Basic); ok && ktyp.Kind() != types.Invalid {
 		w.onFailure(lint.Failure{
diff --git a/rule/cyclomatic.go b/rule/cyclomatic.go
index 23928a37b..904f82ac7 100644
--- a/rule/cyclomatic.go
+++ b/rule/cyclomatic.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"go/ast"
 	"go/token"
+	"sync"
 
 	"github.com/deepsourcelabs/revive/lint"
 )
@@ -13,10 +14,11 @@ import (
 // CyclomaticRule lints given else constructs.
 type CyclomaticRule struct {
 	maxComplexity int
+	sync.Mutex
 }
 
-// Apply applies the rule to given file.
-func (r *CyclomaticRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+func (r *CyclomaticRule) configure(arguments lint.Arguments) {
+	r.Lock()
 	if r.maxComplexity == 0 {
 		checkNumberOfArguments(1, arguments, r.Name())
 
@@ -26,9 +28,16 @@ func (r *CyclomaticRule) Apply(file *lint.File, arguments lint.Arguments) []lint
 		}
 		r.maxComplexity = int(complexity)
 	}
+	r.Unlock()
+}
+
+// Apply applies the rule to given file.
+func (r *CyclomaticRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	r.configure(arguments)
 
 	var failures []lint.Failure
 	fileAst := file.AST
+
 	walker := lintCyclomatic{
 		file:       file,
 		complexity: r.maxComplexity,
diff --git a/rule/defer.go b/rule/defer.go
index f6d47f5f7..68fb51060 100644
--- a/rule/defer.go
+++ b/rule/defer.go
@@ -3,6 +3,7 @@ package rule
 import (
 	"fmt"
 	"go/ast"
+	"sync"
 
 	"github.com/deepsourcelabs/revive/lint"
 )
@@ -10,18 +11,25 @@ import (
 // DeferRule lints unused params in functions.
 type DeferRule struct {
 	allow map[string]bool
+	sync.Mutex
 }
 
-// Apply applies the rule to given file.
-func (r *DeferRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+func (r *DeferRule) configure(arguments lint.Arguments) {
+	r.Lock()
 	if r.allow == nil {
 		r.allow = r.allowFromArgs(arguments)
 	}
+	r.Unlock()
+}
+
+// Apply applies the rule to given file.
+func (r *DeferRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	r.configure(arguments)
+
 	var failures []lint.Failure
 	onFailure := func(failure lint.Failure) {
 		failures = append(failures, failure)
 	}
-
 	w := lintDeferRule{onFailure: onFailure, allow: r.allow}
 
 	ast.Walk(w, file.AST)
diff --git a/rule/exported.go b/rule/exported.go
index 11c4b0316..907bc5ffe 100644
--- a/rule/exported.go
+++ b/rule/exported.go
@@ -5,6 +5,7 @@ import (
 	"go/ast"
 	"go/token"
 	"strings"
+	"sync"
 	"unicode"
 	"unicode/utf8"
 
@@ -17,19 +18,14 @@ type ExportedRule struct {
 	checkPrivateReceivers  bool
 	disableStutteringCheck bool
 	stuttersMsg            string
+	sync.Mutex
 }
 
-// Apply applies the rule to given file.
-func (r *ExportedRule) Apply(file *lint.File, args lint.Arguments) []lint.Failure {
-	var failures []lint.Failure
-
-	if file.IsTest() {
-		return failures
-	}
-
+func (r *ExportedRule) configure(arguments lint.Arguments) {
+	r.Lock()
 	if !r.configured {
 		var sayRepetitiveInsteadOfStutters bool
-		r.checkPrivateReceivers, r.disableStutteringCheck, sayRepetitiveInsteadOfStutters = r.getConf(args)
+		r.checkPrivateReceivers, r.disableStutteringCheck, sayRepetitiveInsteadOfStutters = r.getConf(arguments)
 		r.stuttersMsg = "stutters"
 		if sayRepetitiveInsteadOfStutters {
 			r.stuttersMsg = "is repetitive"
@@ -37,8 +33,20 @@ func (r *ExportedRule) Apply(file *lint.File, args lint.Arguments) []lint.Failur
 
 		r.configured = true
 	}
+	r.Unlock()
+}
+
+// Apply applies the rule to given file.
+func (r *ExportedRule) Apply(file *lint.File, args lint.Arguments) []lint.Failure {
+	r.configure(args)
+
+	var failures []lint.Failure
+	if file.IsTest() {
+		return failures
+	}
 
 	fileAst := file.AST
+
 	walker := lintExported{
 		file:    file,
 		fileAst: fileAst,
@@ -118,7 +126,8 @@ func (w *lintExported) lintFuncDoc(fn *ast.FuncDecl) {
 		}
 		switch name {
 		case "Len", "Less", "Swap":
-			if w.file.Pkg.Sortable[recv] {
+			sortables := w.file.Pkg.Sortable()
+			if sortables[recv] {
 				return
 			}
 		}
diff --git a/rule/file-header.go b/rule/file-header.go
index cc21794fc..4c23aa44f 100644
--- a/rule/file-header.go
+++ b/rule/file-header.go
@@ -3,6 +3,7 @@ package rule
 import (
 	"fmt"
 	"regexp"
+	"sync"
 
 	"github.com/deepsourcelabs/revive/lint"
 )
@@ -10,6 +11,7 @@ import (
 // FileHeaderRule lints given else constructs.
 type FileHeaderRule struct {
 	header string
+	sync.Mutex
 }
 
 var (
@@ -17,8 +19,8 @@ var (
 	singleRegexp = regexp.MustCompile("^//")
 )
 
-// Apply applies the rule to given file.
-func (r *FileHeaderRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+func (r *FileHeaderRule) configure(arguments lint.Arguments) {
+	r.Lock()
 	if r.header == "" {
 		checkNumberOfArguments(1, arguments, r.Name())
 		var ok bool
@@ -27,6 +29,12 @@ func (r *FileHeaderRule) Apply(file *lint.File, arguments lint.Arguments) []lint
 			panic(fmt.Sprintf("invalid argument for \"file-header\" rule: first argument should be a string, got %T", arguments[0]))
 		}
 	}
+	r.Unlock()
+}
+
+// Apply applies the rule to given file.
+func (r *FileHeaderRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	r.configure(arguments)
 
 	failure := []lint.Failure{
 		{
diff --git a/rule/function-length.go b/rule/function-length.go
index c8b0e1747..2906c4ebf 100644
--- a/rule/function-length.go
+++ b/rule/function-length.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"go/ast"
 	"reflect"
+	"sync"
 
 	"github.com/deepsourcelabs/revive/lint"
 )
@@ -12,15 +13,22 @@ import (
 type FunctionLength struct {
 	maxStmt  int
 	maxLines int
+	sync.Mutex
 }
 
-// Apply applies the rule to given file.
-func (r *FunctionLength) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+func (r *FunctionLength) configure(arguments lint.Arguments) {
+	r.Lock()
 	if r.maxLines == 0 {
 		maxStmt, maxLines := r.parseArguments(arguments)
 		r.maxStmt = int(maxStmt)
 		r.maxLines = int(maxLines)
 	}
+	r.Unlock()
+}
+
+// Apply applies the rule to given file.
+func (r *FunctionLength) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	r.configure(arguments)
 
 	var failures []lint.Failure
 
diff --git a/rule/function-result-limit.go b/rule/function-result-limit.go
index 4aeb5c0f4..db09eaa53 100644
--- a/rule/function-result-limit.go
+++ b/rule/function-result-limit.go
@@ -3,6 +3,7 @@ package rule
 import (
 	"fmt"
 	"go/ast"
+	"sync"
 
 	"github.com/deepsourcelabs/revive/lint"
 )
@@ -10,10 +11,11 @@ import (
 // FunctionResultsLimitRule lints given else constructs.
 type FunctionResultsLimitRule struct {
 	max int
+	sync.Mutex
 }
 
-// Apply applies the rule to given file.
-func (r *FunctionResultsLimitRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+func (r *FunctionResultsLimitRule) configure(arguments lint.Arguments) {
+	r.Lock()
 	if r.max == 0 {
 		checkNumberOfArguments(1, arguments, r.Name())
 
@@ -26,6 +28,12 @@ func (r *FunctionResultsLimitRule) Apply(file *lint.File, arguments lint.Argumen
 		}
 		r.max = int(max)
 	}
+	r.Unlock()
+}
+
+// Apply applies the rule to given file.
+func (r *FunctionResultsLimitRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	r.configure(arguments)
 
 	var failures []lint.Failure
 
diff --git a/rule/imports-blacklist.go b/rule/imports-blacklist.go
index 888df899d..5081db3e2 100644
--- a/rule/imports-blacklist.go
+++ b/rule/imports-blacklist.go
@@ -2,6 +2,7 @@ package rule
 
 import (
 	"fmt"
+	"sync"
 
 	"github.com/deepsourcelabs/revive/lint"
 )
@@ -9,16 +10,11 @@ import (
 // ImportsBlacklistRule lints given else constructs.
 type ImportsBlacklistRule struct {
 	blacklist map[string]bool
+	sync.Mutex
 }
 
-// Apply applies the rule to given file.
-func (r *ImportsBlacklistRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
-	var failures []lint.Failure
-
-	if file.IsTest() {
-		return failures // skip, test file
-	}
-
+func (r *ImportsBlacklistRule) configure(arguments lint.Arguments) {
+	r.Lock()
 	if r.blacklist == nil {
 		r.blacklist = make(map[string]bool, len(arguments))
 
@@ -34,6 +30,18 @@ func (r *ImportsBlacklistRule) Apply(file *lint.File, arguments lint.Arguments)
 			r.blacklist[argStr] = true
 		}
 	}
+	r.Unlock()
+}
+
+// Apply applies the rule to given file.
+func (r *ImportsBlacklistRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	r.configure(arguments)
+
+	var failures []lint.Failure
+
+	if file.IsTest() {
+		return failures // skip, test file
+	}
 
 	for _, is := range file.AST.Imports {
 		path := is.Path
diff --git a/rule/line-length-limit.go b/rule/line-length-limit.go
index 0cab76daa..4c9259c86 100644
--- a/rule/line-length-limit.go
+++ b/rule/line-length-limit.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"go/token"
 	"strings"
+	"sync"
 	"unicode/utf8"
 
 	"github.com/deepsourcelabs/revive/lint"
@@ -14,10 +15,11 @@ import (
 // LineLengthLimitRule lints given else constructs.
 type LineLengthLimitRule struct {
 	max int
+	sync.Mutex
 }
 
-// Apply applies the rule to given file.
-func (r *LineLengthLimitRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+func (r *LineLengthLimitRule) configure(arguments lint.Arguments) {
+	r.Lock()
 	if r.max == 0 {
 		checkNumberOfArguments(1, arguments, r.Name())
 
@@ -28,8 +30,15 @@ func (r *LineLengthLimitRule) Apply(file *lint.File, arguments lint.Arguments) [
 
 		r.max = int(max)
 	}
+	r.Unlock()
+}
+
+// Apply applies the rule to given file.
+func (r *LineLengthLimitRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	r.configure(arguments)
 
 	var failures []lint.Failure
+
 	checker := lintLineLengthNum{
 		max:  r.max,
 		file: file,
diff --git a/rule/max-public-structs.go b/rule/max-public-structs.go
index 4db32ab07..a2f2b86bb 100644
--- a/rule/max-public-structs.go
+++ b/rule/max-public-structs.go
@@ -3,6 +3,7 @@ package rule
 import (
 	"go/ast"
 	"strings"
+	"sync"
 
 	"github.com/deepsourcelabs/revive/lint"
 )
@@ -10,10 +11,11 @@ import (
 // MaxPublicStructsRule lints given else constructs.
 type MaxPublicStructsRule struct {
 	max int64
+	sync.Mutex
 }
 
-// Apply applies the rule to given file.
-func (r *MaxPublicStructsRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+func (r *MaxPublicStructsRule) configure(arguments lint.Arguments) {
+	r.Lock()
 	if r.max < 1 {
 		checkNumberOfArguments(1, arguments, r.Name())
 
@@ -23,10 +25,17 @@ func (r *MaxPublicStructsRule) Apply(file *lint.File, arguments lint.Arguments)
 		}
 		r.max = max
 	}
+	r.Unlock()
+}
+
+// Apply applies the rule to given file.
+func (r *MaxPublicStructsRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	r.configure(arguments)
 
 	var failures []lint.Failure
 
 	fileAst := file.AST
+
 	walker := &lintMaxPublicStructs{
 		fileAst: fileAst,
 		onFailure: func(failure lint.Failure) {
diff --git a/rule/nested-structs.go b/rule/nested-structs.go
index a9403bacc..d087ffa4e 100644
--- a/rule/nested-structs.go
+++ b/rule/nested-structs.go
@@ -10,13 +10,9 @@ import (
 type NestedStructs struct{}
 
 // Apply applies the rule to given file.
-func (r *NestedStructs) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+func (r *NestedStructs) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
 	var failures []lint.Failure
 
-	if len(arguments) > 0 {
-		panic(r.Name() + " doesn't take any arguments")
-	}
-
 	walker := &lintNestedStructs{
 		fileAST: file.AST,
 		onFailure: func(failure lint.Failure) {
diff --git a/rule/unhandled-error.go b/rule/unhandled-error.go
index 62eb9e9d1..7d849a54e 100644
--- a/rule/unhandled-error.go
+++ b/rule/unhandled-error.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"go/ast"
 	"go/types"
+	"sync"
 
 	"github.com/deepsourcelabs/revive/lint"
 )
@@ -11,16 +12,17 @@ import (
 // UnhandledErrorRule lints given else constructs.
 type UnhandledErrorRule struct {
 	ignoreList ignoreListType
+	sync.Mutex
 }
 
 type ignoreListType map[string]struct{}
 
-// Apply applies the rule to given file.
-func (r *UnhandledErrorRule) Apply(file *lint.File, args lint.Arguments) []lint.Failure {
+func (r *UnhandledErrorRule) configure(arguments lint.Arguments) {
+	r.Lock()
 	if r.ignoreList == nil {
-		r.ignoreList = make(ignoreListType, len(args))
+		r.ignoreList = make(ignoreListType, len(arguments))
 
-		for _, arg := range args {
+		for _, arg := range arguments {
 			argStr, ok := arg.(string)
 			if !ok {
 				panic(fmt.Sprintf("Invalid argument to the unhandled-error rule. Expecting a string, got %T", arg))
@@ -29,6 +31,12 @@ func (r *UnhandledErrorRule) Apply(file *lint.File, args lint.Arguments) []lint.
 			r.ignoreList[argStr] = struct{}{}
 		}
 	}
+	r.Unlock()
+}
+
+// Apply applies the rule to given file.
+func (r *UnhandledErrorRule) Apply(file *lint.File, args lint.Arguments) []lint.Failure {
+	r.configure(args)
 
 	var failures []lint.Failure
 
diff --git a/rule/var-naming.go b/rule/var-naming.go
index 5ecab37c2..6e10ce624 100644
--- a/rule/var-naming.go
+++ b/rule/var-naming.go
@@ -5,6 +5,7 @@ import (
 	"go/ast"
 	"go/token"
 	"strings"
+	"sync"
 
 	"github.com/deepsourcelabs/revive/lint"
 )
@@ -14,12 +15,11 @@ type VarNamingRule struct {
 	configured bool
 	whitelist  []string
 	blacklist  []string
+	sync.Mutex
 }
 
-// Apply applies the rule to given file.
-func (r *VarNamingRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
-	var failures []lint.Failure
-
+func (r *VarNamingRule) configure(arguments lint.Arguments) {
+	r.Lock()
 	if !r.configured {
 		if len(arguments) >= 1 {
 			r.whitelist = getList(arguments[0], "whitelist")
@@ -30,8 +30,17 @@ func (r *VarNamingRule) Apply(file *lint.File, arguments lint.Arguments) []lint.
 		}
 		r.configured = true
 	}
+	r.Unlock()
+}
+
+// Apply applies the rule to given file.
+func (r *VarNamingRule) Apply(file *lint.File, arguments lint.Arguments) []lint.Failure {
+	r.configure(arguments)
+
+	var failures []lint.Failure
 
 	fileAst := file.AST
+
 	walker := lintNames{
 		file:      file,
 		fileAst:   fileAst,