diff --git a/src/cmd/vet/buildtag.go b/src/cmd/vet/buildtag.go
index 5fa08b62d7e..80d8f819240 100644
--- a/src/cmd/vet/buildtag.go
+++ b/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)
diff --git a/src/cmd/vet/main.go b/src/cmd/vet/main.go
index 34c5297b89f..ffe988b9fce 100644
--- a/src/cmd/vet/main.go
+++ b/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()
diff --git a/src/cmd/vet/method.go b/src/cmd/vet/method.go
index baefa554a40..b13ce2fcb56 100644
--- a/src/cmd/vet/method.go
+++ b/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)
 		}
 	}
diff --git a/src/cmd/vet/print.go b/src/cmd/vet/print.go
index 9998ddae074..dae307695b2 100644
--- a/src/cmd/vet/print.go
+++ b/src/cmd/vet/print.go
@@ -237,23 +237,24 @@ 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] == '%' {
-			state := f.parsePrintfVerb(call, name, format[i:], firstArg, argNum)
-			if state == nil {
-				return
-			}
-			w = len(state.format)
-			if !f.okPrintfArg(call, state) { // One error per format is enough.
-				return
-			}
-			if len(state.argNums) > 0 {
-				// Continue with the next sequential argument.
-				argNum = state.argNums[len(state.argNums)-1] + 1
-			}
-			for _, n := range state.argNums {
-				if n >= maxArgNum {
-					maxArgNum = n + 1
-				}
+		if format[i] != '%' {
+			continue
+		}
+		state := f.parsePrintfVerb(call, name, format[i:], firstArg, argNum)
+		if state == nil {
+			return
+		}
+		w = len(state.format)
+		if !f.okPrintfArg(call, state) { // One error per format is enough.
+			return
+		}
+		if len(state.argNums) > 0 {
+			// Continue with the next sequential argument.
+			argNum = state.argNums[len(state.argNums)-1] + 1
+		}
+		for _, n := range state.argNums {
+			if n >= maxArgNum {
+				maxArgNum = n + 1
 			}
 		}
 	}
@@ -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.
diff --git a/src/cmd/vet/unused.go b/src/cmd/vet/unused.go
index df2317a4365..02fcd841cd0 100644
--- a/src/cmd/vet/unused.go
+++ b/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] {