all: fix staticcheck warnings

This is a loose collection of small fixes flagged by staticcheck:

  - dead code
  - regexp expressions not using backticks (`foobar` / "foobar")
  - redundant types of slice and map initializers
  - misc other fixes

Not all of these seem very useful to me, but in particular dead code is
nice to fix. I've fixed them all just so that if there are problems,
they aren't hidden in the noise of less useful issues.

builder/ar.go

@@ -27,7 +27,7 @@ func makeArchive(archivePath string, objs []string) error {
 	arwriter := ar.NewWriter(arfile)
 	err = arwriter.WriteGlobalHeader()
 	if err != nil {
-		return &os.PathError{"write ar header", archivePath, err}
+		return &os.PathError{Op: "write ar header", Path: archivePath, Err: err}
 	}
 
 	// Open all object files and read the symbols for the symbol table.

builder/uf2.go

@@ -141,11 +141,13 @@ func split(input []byte, limit int) [][]byte {
 	var block []byte
 	output := make([][]byte, 0, len(input)/limit+1)
 	for len(input) >= limit {
+		// add all blocks
 		block, input = input[:limit], input[limit:]
 		output = append(output, block)
 	}
 	if len(input) > 0 {
-		output = append(output, input[:len(input)])
+		// add remaining block (that isn't full sized)
+		output = append(output, input)
 	}
 	return output
 }

cgo/cgo.go

@@ -124,17 +124,17 @@ var cgoAliases = map[string]string{
 // builtinAliases are handled specially because they only exist on the Go side
 // of CGo, not on the CGo side (they're prefixed with "_Cgo_" there).
 var builtinAliases = map[string]struct{}{
-	"char":      struct{}{},
-	"schar":     struct{}{},
-	"uchar":     struct{}{},
-	"short":     struct{}{},
-	"ushort":    struct{}{},
-	"int":       struct{}{},
-	"uint":      struct{}{},
-	"long":      struct{}{},
-	"ulong":     struct{}{},
-	"longlong":  struct{}{},
-	"ulonglong": struct{}{},
+	"char":      {},
+	"schar":     {},
+	"uchar":     {},
+	"short":     {},
+	"ushort":    {},
+	"int":       {},
+	"uint":      {},
+	"long":      {},
+	"ulong":     {},
+	"longlong":  {},
+	"ulonglong": {},
 }
 
 // cgoTypes lists some C types with ambiguous sizes that must be retrieved
@@ -224,7 +224,7 @@ func Process(files []*ast.File, dir string, fset *token.FileSet, cflags []string
 				Specs: []ast.Spec{
 					&ast.ValueSpec{
 						Names: []*ast.Ident{
-							&ast.Ident{
+							{
 								Name: "_",
 								Obj: &ast.Object{
 									Kind: ast.Var,
@@ -494,7 +494,7 @@ func (p *cgoPackage) addFuncDecls() {
 		if fn.variadic {
 			decl.Doc = &ast.CommentGroup{
 				List: []*ast.Comment{
-					&ast.Comment{
+					{
 						Slash: fn.pos,
 						Text:  "//go:variadic",
 					},
@@ -505,7 +505,7 @@ func (p *cgoPackage) addFuncDecls() {
 		for i, arg := range fn.args {
 			args[i] = &ast.Field{
 				Names: []*ast.Ident{
-					&ast.Ident{
+					{
 						NamePos: fn.pos,
 						Name:    arg.name,
 						Obj: &ast.Object{
@@ -553,7 +553,7 @@ func (p *cgoPackage) addFuncPtrDecls() {
 			Name: "C." + name + "$funcaddr",
 		}
 		valueSpec := &ast.ValueSpec{
-			Names: []*ast.Ident{&ast.Ident{
+			Names: []*ast.Ident{{
 				NamePos: fn.pos,
 				Name:    "C." + name + "$funcaddr",
 				Obj:     obj,
@@ -603,7 +603,7 @@ func (p *cgoPackage) addConstDecls() {
 			Name: "C." + name,
 		}
 		valueSpec := &ast.ValueSpec{
-			Names: []*ast.Ident{&ast.Ident{
+			Names: []*ast.Ident{{
 				NamePos: constVal.pos,
 				Name:    "C." + name,
 				Obj:     obj,
@@ -644,7 +644,7 @@ func (p *cgoPackage) addVarDecls() {
 			Name: "C." + name,
 		}
 		valueSpec := &ast.ValueSpec{
-			Names: []*ast.Ident{&ast.Ident{
+			Names: []*ast.Ident{{
 				NamePos: global.pos,
 				Name:    "C." + name,
 				Obj:     obj,
@@ -845,9 +845,9 @@ func (p *cgoPackage) makeUnionField(typ *elaboratedTypeInfo) *ast.StructType {
 		Struct: typ.typeExpr.Struct,
 		Fields: &ast.FieldList{
 			Opening: typ.typeExpr.Fields.Opening,
-			List: []*ast.Field{&ast.Field{
+			List: []*ast.Field{{
 				Names: []*ast.Ident{
-					&ast.Ident{
+					{
 						NamePos: typ.typeExpr.Fields.Opening,
 						Name:    "$union",
 					},
@@ -928,9 +928,9 @@ func (p *cgoPackage) createUnionAccessor(field *ast.Field, typeName string) {
 		Recv: &ast.FieldList{
 			Opening: pos,
 			List: []*ast.Field{
-				&ast.Field{
+				{
 					Names: []*ast.Ident{
-						&ast.Ident{
+						{
 							NamePos: pos,
 							Name:    "union",
 						},
@@ -959,7 +959,7 @@ func (p *cgoPackage) createUnionAccessor(field *ast.Field, typeName string) {
 			},
 			Results: &ast.FieldList{
 				List: []*ast.Field{
-					&ast.Field{
+					{
 						Type: &ast.StarExpr{
 							Star: pos,
 							X:    field.Type,
@@ -1038,9 +1038,9 @@ func (p *cgoPackage) createBitfieldGetter(bitfield bitfieldInfo, typeName string
 		Recv: &ast.FieldList{
 			Opening: bitfield.pos,
 			List: []*ast.Field{
-				&ast.Field{
+				{
 					Names: []*ast.Ident{
-						&ast.Ident{
+						{
 							NamePos: bitfield.pos,
 							Name:    "s",
 							Obj: &ast.Object{
@@ -1074,7 +1074,7 @@ func (p *cgoPackage) createBitfieldGetter(bitfield bitfieldInfo, typeName string
 			},
 			Results: &ast.FieldList{
 				List: []*ast.Field{
-					&ast.Field{
+					{
 						Type: bitfield.field.Type,
 					},
 				},
@@ -1191,9 +1191,9 @@ func (p *cgoPackage) createBitfieldSetter(bitfield bitfieldInfo, typeName string
 		Recv: &ast.FieldList{
 			Opening: bitfield.pos,
 			List: []*ast.Field{
-				&ast.Field{
+				{
 					Names: []*ast.Ident{
-						&ast.Ident{
+						{
 							NamePos: bitfield.pos,
 							Name:    "s",
 							Obj: &ast.Object{
@@ -1224,9 +1224,9 @@ func (p *cgoPackage) createBitfieldSetter(bitfield bitfieldInfo, typeName string
 			Params: &ast.FieldList{
 				Opening: bitfield.pos,
 				List: []*ast.Field{
-					&ast.Field{
+					{
 						Names: []*ast.Ident{
-							&ast.Ident{
+							{
 								NamePos: bitfield.pos,
 								Name:    "value",
 								Obj:     nil,

cgo/cgo_test.go

@@ -96,7 +96,7 @@ func TestCGo(t *testing.T) {
 			if err != nil {
 				t.Errorf("could not write out CGo AST: %v", err)
 			}
-			actual := normalizeResult(string(buf.Bytes()))
+			actual := normalizeResult(buf.String())
 
 			// Read the file with the expected output, to compare against.
 			outfile := filepath.Join("testdata", name+".out.go")

cgo/libclang.go

@@ -203,7 +203,7 @@ func tinygo_clang_globals_visitor(c, parent C.GoCXCursor, client_data C.CXClient
 		if resultType.kind != C.CXType_Void {
 			fn.results = &ast.FieldList{
 				List: []*ast.Field{
-					&ast.Field{
+					{
 						Type: p.makeASTType(resultType, pos),
 					},
 				},
@@ -775,7 +775,7 @@ func tinygo_clang_struct_visitor(c, parent C.GoCXCursor, client_data C.CXClientD
 	}
 	*inBitfield = false
 	field.Names = []*ast.Ident{
-		&ast.Ident{
+		{
 			NamePos: pos,
 			Name:    name,
 			Obj: &ast.Object{
@@ -796,8 +796,12 @@ func tinygo_clang_enum_visitor(c, parent C.GoCXCursor, client_data C.CXClientDat
 	pos := p.getCursorPosition(c)
 	value := C.tinygo_clang_getEnumConstantDeclValue(c)
 	p.constants[name] = constantInfo{
-		expr: &ast.BasicLit{pos, token.INT, strconv.FormatInt(int64(value), 10)},
-		pos:  pos,
+		expr: &ast.BasicLit{
+			ValuePos: pos,
+			Kind:     token.INT,
+			Value:    strconv.FormatInt(int64(value), 10),
+		},
+		pos: pos,
 	}
 	return C.CXChildVisit_Continue
 }

compiler/asserts.go

@@ -164,11 +164,9 @@ func (b *builder) createChanBoundsCheck(elementSize uint64, bufSize llvm.Value,
 	if bufSize.Type().IntTypeWidth() < b.uintptrType.IntTypeWidth() {
 		if bufSizeType.Info()&types.IsUnsigned != 0 {
 			// Unsigned, so zero-extend to uint type.
-			bufSizeType = types.Typ[types.Uint]
 			bufSize = b.CreateZExt(bufSize, b.intType, "")
 		} else {
 			// Signed, so sign-extend to int type.
-			bufSizeType = types.Typ[types.Int]
 			bufSize = b.CreateSExt(bufSize, b.intType, "")
 		}
 	}

compiler/calls.go

@@ -63,10 +63,10 @@ func (c *compilerContext) expandFormalParamType(t llvm.Type, name string, goType
 	case llvm.StructTypeKind:
 		fieldInfos := c.flattenAggregateType(t, name, goType)
 		if len(fieldInfos) <= maxFieldsPerParam {
+			// managed to expand this parameter
 			return fieldInfos
-		} else {
-			// failed to lower
 		}
+		// failed to expand this parameter: too many fields
 	}
 	// TODO: split small arrays
 	return []paramInfo{

compiler/compiler.go

@@ -33,9 +33,6 @@ func init() {
 	llvm.InitializeAllAsmPrinters()
 }
 
-// The TinyGo import path.
-const tinygoPath = "github.com/tinygo-org/tinygo"
-
 // Config is the configuration for the compiler. Most settings should be copied
 // directly from compileopts.Config, it recreated here to decouple the compiler
 // package a bit and because it makes caching easier.
@@ -141,7 +138,6 @@ type builder struct {
 	blockExits        map[*ssa.BasicBlock]llvm.BasicBlock // these are the exit blocks
 	currentBlock      *ssa.BasicBlock
 	phis              []phiNode
-	taskHandle        llvm.Value
 	deferPtr          llvm.Value
 	difunc            llvm.Metadata
 	dilocals          map[*types.Var]llvm.Metadata
@@ -233,10 +229,6 @@ func Sizes(machine llvm.TargetMachine) types.Sizes {
 	targetData := machine.CreateTargetData()
 	defer targetData.Dispose()
 
-	intPtrType := targetData.IntPtrType()
-	if intPtrType.IntTypeWidth()/8 <= 32 {
-	}
-
 	var intWidth int
 	if targetData.PointerSize() <= 4 {
 		// 8, 16, 32 bits targets
@@ -251,7 +243,7 @@ func Sizes(machine llvm.TargetMachine) types.Sizes {
 	return &stdSizes{
 		IntSize:  int64(intWidth / 8),
 		PtrSize:  int64(targetData.PointerSize()),
-		MaxAlign: int64(targetData.PrefTypeAlignment(intPtrType)),
+		MaxAlign: int64(targetData.PrefTypeAlignment(targetData.IntPtrType())),
 	}
 }
 
@@ -452,7 +444,7 @@ func (c *compilerContext) createDIType(typ types.Type) llvm.Metadata {
 			AlignInBits: uint32(c.targetData.ABITypeAlignment(llvmType)) * 8,
 			ElementType: c.getDIType(typ.Elem()),
 			Subscripts: []llvm.DISubrange{
-				llvm.DISubrange{
+				{
 					Lo:    0,
 					Count: typ.Len(),
 				},

compiler/errors.go

@@ -3,7 +3,6 @@ package compiler
 // This file contains some utility functions related to error handling.
 
 import (
-	"go/scanner"
 	"go/token"
 	"go/types"
 	"path/filepath"
@@ -20,20 +19,11 @@ func (c *compilerContext) makeError(pos token.Pos, msg string) types.Error {
 	}
 }
 
+// addError adds a new compiler diagnostic with the given location and message.
 func (c *compilerContext) addError(pos token.Pos, msg string) {
 	c.diagnostics = append(c.diagnostics, c.makeError(pos, msg))
 }
 
-// errorAt returns an error value at the location of the instruction.
-// The location information may not be complete as it depends on debug
-// information in the IR.
-func errorAt(inst llvm.Value, msg string) scanner.Error {
-	return scanner.Error{
-		Pos: getPosition(inst),
-		Msg: msg,
-	}
-}
-
 // getPosition returns the position information for the given value, as far as
 // it is available.
 func getPosition(val llvm.Value) token.Position {

compiler/inlineasm.go

@@ -72,7 +72,7 @@ func (b *builder) createInlineAsmFull(instr *ssa.CallCommon) (llvm.Value, error)
 	args := []llvm.Value{}
 	constraints := []string{}
 	hasOutput := false
-	asmString = regexp.MustCompile("\\{\\}").ReplaceAllStringFunc(asmString, func(s string) string {
+	asmString = regexp.MustCompile(`\{\}`).ReplaceAllStringFunc(asmString, func(s string) string {
 		hasOutput = true
 		return "$0"
 	})
@@ -80,7 +80,7 @@ func (b *builder) createInlineAsmFull(instr *ssa.CallCommon) (llvm.Value, error)
 		constraints = append(constraints, "=&r")
 		registerNumbers[""] = 0
 	}
-	asmString = regexp.MustCompile("\\{[a-zA-Z]+\\}").ReplaceAllStringFunc(asmString, func(s string) string {
+	asmString = regexp.MustCompile(`\{[a-zA-Z]+\}`).ReplaceAllStringFunc(asmString, func(s string) string {
 		// TODO: skip strings like {r4} etc. that look like ARM push/pop
 		// instructions.
 		name := s[1 : len(s)-1]

compiler/llvm.go

@@ -8,21 +8,6 @@ import (
 // This file contains helper functions for LLVM that are not exposed in the Go
 // bindings.
 
-// Return a list of values (actually, instructions) where this value is used as
-// an operand.
-func getUses(value llvm.Value) []llvm.Value {
-	if value.IsNil() {
-		return nil
-	}
-	var uses []llvm.Value
-	use := value.FirstUse()
-	for !use.IsNil() {
-		uses = append(uses, use.User())
-		use = use.NextUse()
-	}
-	return uses
-}
-
 // createTemporaryAlloca creates a new alloca in the entry block and adds
 // lifetime start information in the IR signalling that the alloca won't be used
 // before this point.