cmd/vet: remove two unused parameters and simplify

The isStar and directory function parameters have been unused ever since
they were introduced. Remove them.

While at it, apply some other minor simplifications, such as simplifying
a HasPrefix if and using an early continue to unindent many lines of
code.

Change-Id: I8d57353e9ec10cdb59c5388cf6152ce0ec17bdba
Reviewed-on: https://go-review.googlesource.com/62030
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Marvin Stenger <marvin.stenger94@gmail.com>

src/cmd/vet/buildtag.go

@@ -69,9 +69,7 @@ func checkBuildTag(name string, data []byte) {
 						setExit(1)
 						break Args
 					}
-					if strings.HasPrefix(elem, "!") {
-						elem = elem[1:]
-					}
+					elem = strings.TrimPrefix(elem, "!")
 					for _, c := range elem {
 						if !unicode.IsLetter(c) && !unicode.IsDigit(c) && c != '_' && c != '.' {
 							fmt.Fprintf(os.Stderr, "%s:%d: invalid non-alphanumeric build constraint: %s\n", name, i+1, arg)

src/cmd/vet/main.go

@@ -250,7 +250,7 @@ func main() {
 		}
 		os.Exit(exitCode)
 	}
-	if doPackage(".", flag.Args(), nil) == nil {
+	if doPackage(flag.Args(), nil) == nil {
 		warnf("no files checked")
 	}
 	os.Exit(exitCode)
@@ -290,12 +290,12 @@ func doPackageDir(directory string) {
 	names = append(names, pkg.TestGoFiles...) // These are also in the "foo" package.
 	names = append(names, pkg.SFiles...)
 	prefixDirectory(directory, names)
-	basePkg := doPackage(directory, names, nil)
+	basePkg := doPackage(names, nil)
 	// Is there also a "foo_test" package? If so, do that one as well.
 	if len(pkg.XTestGoFiles) > 0 {
 		names = pkg.XTestGoFiles
 		prefixDirectory(directory, names)
-		doPackage(directory, names, basePkg)
+		doPackage(names, basePkg)
 	}
 }
 
@@ -312,7 +312,7 @@ type Package struct {
 
 // doPackage analyzes the single package constructed from the named files.
 // It returns the parsed Package or nil if none of the files have been checked.
-func doPackage(directory string, names []string, basePkg *Package) *Package {
+func doPackage(names []string, basePkg *Package) *Package {
 	var files []*File
 	var astFiles []*ast.File
 	fs := token.NewFileSet()

src/cmd/vet/method.go

@@ -138,7 +138,7 @@ func typeFlatten(l []*ast.Field) []ast.Expr {
 			t = append(t, f.Type)
 			continue
 		}
-		for _ = range f.Names {
+		for range f.Names {
 			t = append(t, f.Type)
 		}
 	}

src/cmd/vet/print.go

@@ -237,7 +237,9 @@ func (f *File) checkPrintf(call *ast.CallExpr, name string) {
 	maxArgNum := firstArg
 	for i, w := 0, 0; i < len(format); i += w {
 		w = 1
-		if format[i] == '%' {
+		if format[i] != '%' {
+			continue
+		}
 		state := f.parsePrintfVerb(call, name, format[i:], firstArg, argNum)
 		if state == nil {
 			return
@@ -256,7 +258,6 @@ func (f *File) checkPrintf(call *ast.CallExpr, name string) {
 			}
 		}
 	}
-	}
 	// Dotdotdot is hard.
 	if call.Ellipsis.IsValid() && maxArgNum >= len(call.Args)-1 {
 		return
@@ -498,7 +499,7 @@ func (f *File) okPrintfArg(call *ast.CallExpr, state *formatState) (ok bool) {
 	nargs := len(state.argNums)
 	for i := 0; i < nargs-trueArgs; i++ {
 		argNum := state.argNums[i]
-		if !f.argCanBeChecked(call, i, true, state) {
+		if !f.argCanBeChecked(call, i, state) {
 			return
 		}
 		arg := call.Args[argNum]
@@ -511,7 +512,7 @@ func (f *File) okPrintfArg(call *ast.CallExpr, state *formatState) (ok bool) {
 		return true
 	}
 	argNum := state.argNums[len(state.argNums)-1]
-	if !f.argCanBeChecked(call, len(state.argNums)-1, false, state) {
+	if !f.argCanBeChecked(call, len(state.argNums)-1, state) {
 		return false
 	}
 	arg := call.Args[argNum]
@@ -577,7 +578,7 @@ func (f *File) isFunctionValue(e ast.Expr) bool {
 // argCanBeChecked reports whether the specified argument is statically present;
 // it may be beyond the list of arguments or in a terminal slice... argument, which
 // means we can't see it.
-func (f *File) argCanBeChecked(call *ast.CallExpr, formatArg int, isStar bool, state *formatState) bool {
+func (f *File) argCanBeChecked(call *ast.CallExpr, formatArg int, state *formatState) bool {
 	argNum := state.argNums[formatArg]
 	if argNum < 0 {
 		// Shouldn't happen, so catch it with prejudice.

src/cmd/vet/unused.go

@@ -82,7 +82,7 @@ func checkUnusedResult(f *File, n ast.Node) {
 		}
 	} else if !ok {
 		// package-qualified function (e.g. fmt.Errorf)
-		obj, _ := f.pkg.uses[selector.Sel]
+		obj := f.pkg.uses[selector.Sel]
 		if obj, ok := obj.(*types.Func); ok {
 			qname := obj.Pkg().Path() + "." + obj.Name()
 			if unusedFuncs[qname] {