Fix linter issues: staticcheck (covered by megacheck, along with gosimple and unused)

Makefile

@@ -116,16 +116,15 @@ gometalinter: require-gometalinter
 	    --enable=gochecknoinits \
 	    --enable=gofmt \
 	    --enable=goimports \
-	    --enable=gosimple \
 	    --enable=gotype \
 	    --enable=gotypex \
 	    --enable=ineffassign \
 	    --enable=interfacer \
 	    --enable=maligned \
+	    --enable=megacheck \
 	    --enable=misspell \
 	    --enable=nakedret \
 	    --enable=unparam \
-	    --enable=unused \
 	    --enable=vet \
 	    --exclude "^internal/.*\.pb\.go" \
 	    --exclude "^pql/pql.peg.go" \

attr_test.go

@@ -164,18 +164,25 @@ func BenchmarkAttrStore_Duplicate(b *testing.B) {
 	// Update attributes with an existing subset.
 	cpuN := runtime.GOMAXPROCS(0)
 	var wg sync.WaitGroup
+	errchan := make(chan error)
 	for i := 0; i < cpuN; i++ {
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
 			for j := 0; j < b.N/cpuN; j++ {
 				if err := s.SetAttrs(uint64(j%n), map[string]interface{}{"A": int64(100), "B": "foo", "D": 100.2}); err != nil {
-					b.Fatal(err)
+					errchan <- err
 				}
 			}
 		}()
 	}
-	wg.Wait()
+	go func() {
+		wg.Wait()
+		close(errchan)
+	}()
+	if err := <-errchan; err != nil {
+		b.Fatal(err)
+	}
 }
 
 // MustOpenAttrStore returns a new, opened attribute store at a temporary path. Panic on error.

http/client_test.go

@@ -128,12 +128,12 @@ func TestClient_MultiNode(t *testing.T) {
 		Remote: false,
 	}
 
-	result, err := client[0].Query(context.Background(), "i", queryRequest)
+	_, err = client[0].Query(context.Background(), "i", queryRequest)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	result, err = client[0].Query(context.Background(), "i", queryRequest)
+	result, err := client[0].Query(context.Background(), "i", queryRequest)
 	if err != nil {
 		t.Fatal(err)
 	}

lru/lru.go

@@ -83,7 +83,7 @@ func (c *Cache) Get(key Key) (value interface{}, ok bool) {
 }
 
 // remove removes the provided key from the cache.
-func (c *Cache) remove(key Key) { // nolint: unused
+func (c *Cache) remove(key Key) { // nolint: megacheck
 	if c.cache == nil {
 		return
 	}
@@ -121,7 +121,7 @@ func (c *Cache) Len() int {
 }
 
 // clear purges all stored items from the cache.
-func (c *Cache) clear() { // nolint: unused
+func (c *Cache) clear() { // nolint: megacheck
 	if c.OnEvicted != nil {
 		for _, e := range c.cache {
 			kv := e.Value.(*entry)

pql/pqlpeg_test.go

@@ -31,7 +31,7 @@ SetBit(Union(Zitmap(row==4), Intersect(Qitmap(blah>4), Ritmap(field="http://zoo9
 		t.Fatalf("Failed, got: %s", q)
 	}
 
-	q, err = ParseString("C(a=falsen0)")
+	_, err = ParseString("C(a=falsen0)")
 	if err != nil {
 		t.Fatalf("falsen0 should have been parsed as a string")
 	}

server/config_test.go

@@ -54,6 +54,9 @@ func TestDuration(t *testing.T) {
 	}
 
 	err = d.UnmarshalText([]byte("3m2s"))
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
 	v, _ = d.MarshalText()
 	if !reflect.DeepEqual(b, v) {
 		t.Fatalf("Unexpected marshalled value %v", v)