all: fix warnings pointed to by golangci-lint

Update #977

pkg/compiler/consts.go

@@ -164,10 +164,9 @@ func (comp *compiler) assignSyscallNumbers(consts map[string]uint64) {
 // Updates desc and returns set of unsupported syscalls and flags.
 func (comp *compiler) patchConsts(consts map[string]uint64) {
 	for _, decl := range comp.desc.Nodes {
-		switch decl.(type) {
+		switch n := decl.(type) {
 		case *ast.IntFlags:
 			// Unsupported flag values are dropped.
-			n := decl.(*ast.IntFlags)
 			var values []*ast.Int
 			for _, v := range n.Values {
 				if comp.patchIntConst(&v.Value, &v.Ident, consts, nil) {

pkg/csource/csource_test.go

@@ -60,7 +60,7 @@ func TestGenerate(t *testing.T) {
 }
 
 func testTarget(t *testing.T, target *prog.Target, full bool) {
-	seed := int64(time.Now().UnixNano())
+	seed := time.Now().UnixNano()
 	if os.Getenv("TRAVIS") != "" {
 		seed = 0 // required for deterministic coverage reports
 	}

pkg/ifuzz/ifuzz_test.go

@@ -36,7 +36,7 @@ func TestMode(t *testing.T) {
 }
 
 func TestDecode(t *testing.T) {
-	seed := int64(time.Now().UnixNano())
+	seed := time.Now().UnixNano()
 	if os.Getenv("TRAVIS") != "" {
 		seed = 0 // required for deterministic coverage reports
 	}

pkg/ipc/ipc_test.go

@@ -37,7 +37,7 @@ func initTest(t *testing.T) (*prog.Target, rand.Source, int, EnvFlags) {
 	if testing.Short() {
 		iters = 10
 	}
-	seed := int64(time.Now().UnixNano())
+	seed := time.Now().UnixNano()
 	if os.Getenv("TRAVIS") != "" {
 		seed = 0 // required for deterministic coverage reports
 	}

pkg/repro/repro_test.go

@@ -18,7 +18,7 @@ func initTest(t *testing.T) (*rand.Rand, int) {
 	if testing.Short() {
 		iters = 100
 	}
-	seed := int64(time.Now().UnixNano())
+	seed := time.Now().UnixNano()
 	if os.Getenv("TRAVIS") != "" {
 		seed = 0 // required for deterministic coverage reports
 	}

prog/export_test.go

@@ -32,7 +32,7 @@ func initTargetTest(t *testing.T, os, arch string) *Target {
 }
 
 func randSource(t *testing.T) rand.Source {
-	seed := int64(time.Now().UnixNano())
+	seed := time.Now().UnixNano()
 	if os.Getenv("TRAVIS") != "" {
 		seed = 0 // required for deterministic coverage reports
 	}

vm/adb/adb.go

@@ -328,12 +328,11 @@ func (inst *instance) getBatteryLevel(numRetry int) (int, error) {
 			// sleep for 5 seconds before retrying
 			time.Sleep(5 * time.Second)
 			out, err = inst.adb("shell", "dumpsys battery | grep level:")
-		} else {
-			if err != nil {
-				return 0, err
-			}
 		}
 	}
+	if err != nil {
+		return 0, err
+	}
 	val := 0
 	for _, c := range out {
 		if c >= '0' && c <= '9' {

vm/gvisor/gvisor.go

@@ -336,7 +336,7 @@ func (inst *instance) Diagnose() ([]byte, bool) {
 
 func init() {
 	if os.Getenv("SYZ_GVISOR_PROXY") != "" {
-		fmt.Fprintf(os.Stderr, initStartMsg)
+		fmt.Fprint(os.Stderr, initStartMsg)
 		select {}
 	}
 }