Support generics

.golangci.yml

@@ -15,13 +15,17 @@ linters:
   disable-all: true
   enable:
     - asciicheck
+    - bidichk
     - bodyclose
     - deadcode
     - depguard
     - dogsled
     - dupl
     - durationcheck
     - errcheck
+    - errchkjson
+    - errname
+    - execinquery
     - exhaustive
     - exportloopref
     - forbidigo
@@ -51,9 +55,11 @@ linters:
     - misspell
     - nakedret
     - nilerr
+    - nilnil
     - nestif
     - noctx
     - nolintlint
+    - nosprintfhostport
     - prealloc
     - predeclared
     - revive
@@ -63,6 +69,7 @@ linters:
     - structcheck
     - stylecheck
     - tagliatelle
+    - tenv
     - thelper
     - typecheck
     - unconvert

go.mod

@@ -3,11 +3,11 @@ module github.com/Antonboom/errname
 go 1.18
 
 require (
-	golang.org/x/sys v0.0.0-20220406163625-3f8b81556e12 // indirect
+	golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a // indirect
 	golang.org/x/tools v0.1.10
 )
 
 require (
 	golang.org/x/mod v0.6.0-dev.0.20220106191415-9b9b3d81d5e3 // indirect
-	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
+	golang.org/x/xerrors v0.0.0-20220517211312-f3a8303e98df // indirect
 )

go.sum

@@ -1,8 +1,8 @@
 golang.org/x/mod v0.6.0-dev.0.20220106191415-9b9b3d81d5e3 h1:kQgndtyPBW/JIYERgdxfwMYh3AVStj88WQTlNDi2a+o=
 golang.org/x/mod v0.6.0-dev.0.20220106191415-9b9b3d81d5e3/go.mod h1:3p9vT2HGsQu2K1YbXdKPJLVgG5VJdoTa1poYQBtP1AY=
-golang.org/x/sys v0.0.0-20220406163625-3f8b81556e12 h1:QyVthZKMsyaQwBTJE04jdNN0Pp5Fn9Qga0mrgxyERQM=
-golang.org/x/sys v0.0.0-20220406163625-3f8b81556e12/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a h1:dGzPydgVsqGcTRVwiLJ1jVbufYwmzD3LfVPLKsKg+0k=
+golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/tools v0.1.10 h1:QjFRCZxdOhBJ/UNgnBZLbNV13DlbnK0quyivTnXJM20=
 golang.org/x/tools v0.1.10/go.mod h1:Uh6Zz+xoGYZom868N8YTex3t7RhtHDBrE8Gzo9bV56E=
-golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=
-golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20220517211312-f3a8303e98df h1:5Pf6pFKu98ODmgnpvkJ3kFUOQGGLIzLIkbzUHp47618=
+golang.org/x/xerrors v0.0.0-20220517211312-f3a8303e98df/go.mod h1:K8+ghG5WaK9qNqU5K3HdILfMLy1f3aNYFI/wnl100a8=

pkg/analyzer/analyzer.go

@@ -98,7 +98,7 @@ func run(pass *analysis.Pass) (interface{}, error) {
 		ast.Inspect(f, inspectPkgLevelVarsOnly)
 	}
 
-	return nil, nil
+	return nil, nil //nolint:nilnil
 }
 
 func reportAboutErrorType(pass *analysis.Pass, typePos token.Pos, typeName string, isArrayType bool) {

pkg/analyzer/analyzer_test.go

@@ -10,6 +10,7 @@ func TestErrName(t *testing.T) {
 	pkgs := []string{
 		"regular",
 		"unusual/errortype",
+		"unusual/generics",
 		"unusual/newfunc",
 	}
 	analysistest.Run(t, analysistest.TestData(), New(), pkgs...)

pkg/analyzer/facts.go

@@ -8,10 +8,10 @@ import (
 )
 
 func isMethodError(f *ast.FuncDecl) (typeName string, ok bool) {
-	if f.Recv == nil {
+	if f.Recv == nil || len(f.Recv.List) != 1 {
 		return "", false
 	}
-	if f.Name.Name != "Error" {
+	if f.Name == nil || f.Name.Name != "Error" {
 		return "", false
 	}
 
@@ -26,13 +26,24 @@ func isMethodError(f *ast.FuncDecl) (typeName string, ok bool) {
 
 	var receiverType string
 
-	switch rt := f.Recv.List[0].Type.(type) {
-	case *ast.Ident:
-		receiverType = rt.Name
-	case *ast.StarExpr:
-		if i, ok := rt.X.(*ast.Ident); ok {
-			receiverType = i.Name
+	unwrapIdentName := func(e ast.Expr) string {
+		switch v := e.(type) {
+		case *ast.Ident:
+			return v.Name
+		case *ast.IndexExpr:
+			if i, ok := v.X.(*ast.Ident); ok {
+				return i.Name
+			}
 		}
+		return ""
+	}
+
+	switch rt := f.Recv.List[0].Type; v := rt.(type) {
+	case *ast.Ident, *ast.IndexExpr: // SomeError, SomeError[T]
+		receiverType = unwrapIdentName(rt)
+
+	case *ast.StarExpr: // *SomeError, *SomeError[T]
+		receiverType = unwrapIdentName(v.X)
 	}
 
 	return receiverType, returnType.Name == "string"
@@ -100,7 +111,7 @@ var knownErrConstructors = stringSet{
 	"errors.NewAssertionErrorWithWrappedErrf": {},
 }
 
-func isSentinelError( //nolint:gocognit
+func isSentinelError( //nolint:gocognit,gocyclo
 	v *ast.ValueSpec,
 	pkgAliases map[string]string,
 	allTypes, errorTypes, errorFuncs stringSet,
@@ -151,6 +162,7 @@ func isSentinelError( //nolint:gocognit
 		// var ErrEndOfFile = newErrEndOfFile()
 		// var ErrEndOfFile = new(EndOfFileError)
 		// const ErrEndOfFile = constError("end of file")
+		// var statusCodeError = new(SomePtrError[string])
 		case *ast.Ident:
 			if isErrorType(fun.Name, allTypes, errorTypes) {
 				return varName, true
@@ -161,8 +173,13 @@ func isSentinelError( //nolint:gocognit
 			}
 
 			if fun.Name == "new" && len(vv.Args) == 1 {
-				if i, ok := vv.Args[0].(*ast.Ident); ok {
+				switch i := vv.Args[0].(type) {
+				case *ast.Ident:
 					return varName, isErrorType(i.Name, allTypes, errorTypes)
+				case *ast.IndexExpr:
+					if ii, ok := i.X.(*ast.Ident); ok {
+						return varName, isErrorType(ii.Name, allTypes, errorTypes)
+					}
 				}
 			}
 
@@ -172,19 +189,31 @@ func isSentinelError( //nolint:gocognit
 		}
 
 	// var ErrEndOfFile = &EndOfFileError{}
+	// var ErrOK = &SomePtrError[string]{Code: "200 OK"}
 	case *ast.UnaryExpr:
 		if vv.Op == token.AND { // &
 			if lit, ok := vv.X.(*ast.CompositeLit); ok {
-				if i, ok := lit.Type.(*ast.Ident); ok {
+				switch i := lit.Type.(type) {
+				case *ast.Ident:
 					return varName, isErrorType(i.Name, allTypes, errorTypes)
+				case *ast.IndexExpr:
+					if ii, ok := i.X.(*ast.Ident); ok {
+						return varName, isErrorType(ii.Name, allTypes, errorTypes)
+					}
 				}
 			}
 		}
 
 	// var ErrEndOfFile = EndOfFileError{}
+	// var ErrNotFound = SomeError[string]{Code: "Not Found"}
 	case *ast.CompositeLit:
-		if i, ok := vv.Type.(*ast.Ident); ok {
+		switch i := vv.Type.(type) {
+		case *ast.Ident:
 			return varName, isErrorType(i.Name, allTypes, errorTypes)
+		case *ast.IndexExpr:
+			if ii, ok := i.X.(*ast.Ident); ok {
+				return varName, isErrorType(ii.Name, allTypes, errorTypes)
+			}
 		}
 	}
 

pkg/analyzer/testdata/src/unusual/generics/generic_types.go

@@ -0,0 +1,30 @@
+package generics
+
+type NotErrorGeneric[T float64 | int] struct {
+	Limit T
+}
+
+type SomeError[T ~string] struct{ Code T }
+
+func (e SomeError[T]) Error() string { return string(e.Code) }
+
+type SomePtrError[T ~string] struct{ Code T }
+
+func (e *SomePtrError[T]) Error() string { return string(e.Code) }
+
+type someErr[T ~string] struct{ Code T } //  want "the type name `someErr` should conform to the `xxxError` format"
+func (e someErr[T]) Error() string       { return string(e.Code) }
+
+type SomePtrErr[T ~string] struct{ Code T } //  want "the type name `SomePtrErr` should conform to the `XxxError` format"
+func (e *SomePtrErr[T]) Error() string      { return string(e.Code) }
+
+var (
+	ErrOK = &SomePtrError[string]{Code: "200 OK"}
+	okErr = &SomePtrError[string]{Code: "200 OK"} // want "the variable name `okErr` should conform to the `errXxx` format"
+
+	ErrNotFound = SomeError[string]{Code: "Not Found"}
+	NotFoundErr = SomeError[string]{Code: "Not Found"} // want "the variable name `NotFoundErr` should conform to the `ErrXxx` format"
+
+	statusCodeError       = new(SomePtrError[string]) // want "the variable name `statusCodeError` should conform to the `errXxx` format"
+	ExplicitError   error = new(SomePtrError[string]) // want "the variable name `ExplicitError` should conform to the `ErrXxx` format"
+)