all: fix some lint issues

Make some code more simple.

Change-Id: I801adf0dba5f6c515681345c732dbb907f945419
GitHub-Last-Rev: a505146bac
GitHub-Pull-Request: golang/go#49626
Reviewed-on: https://go-review.googlesource.com/c/go/+/364634
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

src/crypto/des/block.go

@@ -248,9 +248,7 @@ func (c *desCipher) generateSubkeys(keyBytes []byte) {
 // By doing so, we can have the input blocks (four bits each), and the key blocks (six bits each) well-aligned without
 // extra shifts/rotations for alignments.
 func unpack(x uint64) uint64 {
-	var result uint64
-
-	result = ((x>>(6*1))&0xff)<<(8*0) |
+	return ((x>>(6*1))&0xff)<<(8*0) |
 		((x>>(6*3))&0xff)<<(8*1) |
 		((x>>(6*5))&0xff)<<(8*2) |
 		((x>>(6*7))&0xff)<<(8*3) |
@@ -258,6 +256,4 @@ func unpack(x uint64) uint64 {
 		((x>>(6*2))&0xff)<<(8*5) |
 		((x>>(6*4))&0xff)<<(8*6) |
 		((x>>(6*6))&0xff)<<(8*7)
-
-	return result
 }

src/database/sql/example_cli_test.go

@@ -49,10 +49,8 @@ func Example_openDBCLI() {
 	signal.Notify(appSignal, os.Interrupt)
 
 	go func() {
-		select {
-		case <-appSignal:
-			stop()
-		}
+		<-appSignal
+		stop()
 	}()
 
 	Ping(ctx)

src/debug/plan9obj/file.go

@@ -216,8 +216,7 @@ func walksymtab(data []byte, ptrsz int, fn func(sym) error) error {
 			p = p[4:]
 		}
 
-		var typ byte
-		typ = p[0] & 0x7F
+		typ := p[0] & 0x7F
 		s.typ = typ
 		p = p[1:]
 

src/go/build/constraint/expr.go

@@ -345,7 +345,6 @@ func (p *exprParser) lex() {
 	p.i += len(tag)
 	p.tok = p.s[p.pos:p.i]
 	p.isTag = true
-	return
 }
 
 // IsPlusBuild reports whether the line of text is a “// +build” constraint.

src/math/tan.go

@@ -67,10 +67,10 @@ var _tanP = [...]float64{
 }
 var _tanQ = [...]float64{
 	1.00000000000000000000e0,
-	1.36812963470692954678e4,  //0x40cab8a5eeb36572
-	-1.32089234440210967447e6, //0xc13427bc582abc96
-	2.50083801823357915839e7,  //0x4177d98fc2ead8ef
-	-5.38695755929454629881e7, //0xc189afe03cbe5a31
+	1.36812963470692954678e4,  // 0x40cab8a5eeb36572
+	-1.32089234440210967447e6, // 0xc13427bc582abc96
+	2.50083801823357915839e7,  // 0x4177d98fc2ead8ef
+	-5.38695755929454629881e7, // 0xc189afe03cbe5a31
 }
 
 // Tan returns the tangent of the radian argument x.

src/net/http/cookiejar/jar.go

@@ -303,10 +303,8 @@ func canonicalHost(host string) (string, error) {
 			return "", err
 		}
 	}
-	if strings.HasSuffix(host, ".") {
-		// Strip trailing dot from fully qualified domain names.
-		host = host[:len(host)-1]
-	}
+	// Strip trailing dot from fully qualified domain names.
+	host = strings.TrimSuffix(host, ".")
 	encoded, err := toASCII(host)
 	if err != nil {
 		return "", err

src/net/http/httputil/reverseproxy.go

@@ -622,7 +622,6 @@ func (p *ReverseProxy) handleUpgradeResponse(rw http.ResponseWriter, req *http.R
 	go spc.copyToBackend(errc)
 	go spc.copyFromBackend(errc)
 	<-errc
-	return
 }
 
 // switchProtocolCopier exists so goroutines proxying data back and

src/runtime/metrics/description_test.go

@@ -103,7 +103,7 @@ func TestDescriptionDocs(t *testing.T) {
 	}
 	if len(docs) > len(descriptions) {
 	docsLoop:
-		for name, _ := range docs {
+		for name := range docs {
 			for _, d := range descriptions {
 				if name == d.Name {
 					continue docsLoop

src/testing/sub_test.go

@@ -724,7 +724,7 @@ func TestBenchmarkReadMemStatsBeforeFirstRun(t *T) {
 	var first = true
 	Benchmark(func(b *B) {
 		if first && (b.startAllocs == 0 || b.startBytes == 0) {
-			panic(fmt.Sprintf("ReadMemStats not called before first run"))
+			panic("ReadMemStats not called before first run")
 		}
 		first = false
 	})