diff --git a/api/client_test.go b/api/client_test.go
index 53226d7..b1bcfc9 100644
--- a/api/client_test.go
+++ b/api/client_test.go
@@ -89,7 +89,7 @@ func TestClientURL(t *testing.T) {
 			address:  "http://localhost:9090",
 			endpoint: "/test/:param",
 			args: map[string]string{
-				"nonexistant": "content",
+				"nonexistent": "content",
 			},
 			expected: "http://localhost:9090/test/:param",
 		},
diff --git a/prometheus/expvar_collector_test.go b/prometheus/expvar_collector_test.go
index 910dac3..6bcd9b6 100644
--- a/prometheus/expvar_collector_test.go
+++ b/prometheus/expvar_collector_test.go
@@ -78,7 +78,7 @@ func ExampleNewExpvarCollector() {
 		close(metricChan)
 	}()
 	for m := range metricChan {
-		if strings.Index(m.Desc().String(), "expvar_memstats") == -1 {
+		if !strings.Contains(m.Desc().String(), "expvar_memstats") {
 			metric.Reset()
 			m.Write(&metric)
 			metricStrings = append(metricStrings, metric.String())
diff --git a/prometheus/go_collector.go b/prometheus/go_collector.go
index 096454a..122b169 100644
--- a/prometheus/go_collector.go
+++ b/prometheus/go_collector.go
@@ -265,7 +265,7 @@ func (c *goCollector) Collect(ch chan<- Metric) {
 		quantiles[float64(idx+1)/float64(len(stats.PauseQuantiles)-1)] = pq.Seconds()
 	}
 	quantiles[0.0] = stats.PauseQuantiles[0].Seconds()
-	ch <- MustNewConstSummary(c.gcDesc, uint64(stats.NumGC), float64(stats.PauseTotal.Seconds()), quantiles)
+	ch <- MustNewConstSummary(c.gcDesc, uint64(stats.NumGC), stats.PauseTotal.Seconds(), quantiles)
 
 	ch <- MustNewConstMetric(c.goInfoDesc, GaugeValue, 1)
 
diff --git a/prometheus/http.go b/prometheus/http.go
index dd0f819..4d08154 100644
--- a/prometheus/http.go
+++ b/prometheus/http.go
@@ -115,7 +115,7 @@ func decorateWriter(request *http.Request, writer io.Writer) (io.Writer, string)
 	header := request.Header.Get(acceptEncodingHeader)
 	parts := strings.Split(header, ",")
 	for _, part := range parts {
-		part := strings.TrimSpace(part)
+		part = strings.TrimSpace(part)
 		if part == "gzip" || strings.HasPrefix(part, "gzip;") {
 			return gzip.NewWriter(writer), "gzip"
 		}
@@ -139,16 +139,6 @@ var now nower = nowFunc(func() time.Time {
 	return time.Now()
 })
 
-func nowSeries(t ...time.Time) nower {
-	return nowFunc(func() time.Time {
-		defer func() {
-			t = t[1:]
-		}()
-
-		return t[0]
-	})
-}
-
 // InstrumentHandler wraps the given HTTP handler for instrumentation. It
 // registers four metric collectors (if not already done) and reports HTTP
 // metrics to the (newly or already) registered collectors: http_requests_total
@@ -352,10 +342,9 @@ func computeApproximateRequestSize(r *http.Request) <-chan int {
 type responseWriterDelegator struct {
 	http.ResponseWriter
 
-	handler, method string
-	status          int
-	written         int64
-	wroteHeader     bool
+	status      int
+	written     int64
+	wroteHeader bool
 }
 
 func (r *responseWriterDelegator) WriteHeader(code int) {
diff --git a/prometheus/http_test.go b/prometheus/http_test.go
index 0c7fa23..dd89ccf 100644
--- a/prometheus/http_test.go
+++ b/prometheus/http_test.go
@@ -29,6 +29,16 @@ func (b respBody) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	w.Write([]byte(b))
 }
 
+func nowSeries(t ...time.Time) nower {
+	return nowFunc(func() time.Time {
+		defer func() {
+			t = t[1:]
+		}()
+
+		return t[0]
+	})
+}
+
 func TestInstrumentHandler(t *testing.T) {
 	defer func(n nower) {
 		now = n.(nower)
@@ -37,9 +47,9 @@ func TestInstrumentHandler(t *testing.T) {
 	instant := time.Now()
 	end := instant.Add(30 * time.Second)
 	now = nowSeries(instant, end)
-	respBody := respBody("Howdy there!")
+	body := respBody("Howdy there!")
 
-	hndlr := InstrumentHandler("test-handler", respBody)
+	hndlr := InstrumentHandler("test-handler", body)
 
 	opts := SummaryOpts{
 		Subsystem:   "http",
@@ -114,8 +124,8 @@ func TestInstrumentHandler(t *testing.T) {
 	if resp.Code != http.StatusTeapot {
 		t.Fatalf("expected status %d, got %d", http.StatusTeapot, resp.Code)
 	}
-	if string(resp.Body.Bytes()) != "Howdy there!" {
-		t.Fatalf("expected body %s, got %s", "Howdy there!", string(resp.Body.Bytes()))
+	if resp.Body.String() != "Howdy there!" {
+		t.Fatalf("expected body %s, got %s", "Howdy there!", resp.Body.String())
 	}
 
 	out := &dto.Metric{}
diff --git a/prometheus/metric.go b/prometheus/metric.go
index 6213ee8..76035bc 100644
--- a/prometheus/metric.go
+++ b/prometheus/metric.go
@@ -127,20 +127,6 @@ func (s LabelPairSorter) Less(i, j int) bool {
 	return s[i].GetName() < s[j].GetName()
 }
 
-type hashSorter []uint64
-
-func (s hashSorter) Len() int {
-	return len(s)
-}
-
-func (s hashSorter) Swap(i, j int) {
-	s[i], s[j] = s[j], s[i]
-}
-
-func (s hashSorter) Less(i, j int) bool {
-	return s[i] < s[j]
-}
-
 type invalidMetric struct {
 	desc *Desc
 	err  error
diff --git a/prometheus/process_collector.go b/prometheus/process_collector.go
index 32ac74a..b80adc6 100644
--- a/prometheus/process_collector.go
+++ b/prometheus/process_collector.go
@@ -16,7 +16,6 @@ package prometheus
 import "github.com/prometheus/procfs"
 
 type processCollector struct {
-	pid             int
 	collectFn       func(chan<- Metric)
 	pidFn           func() (int, error)
 	cpuTotal        *Desc
diff --git a/prometheus/process_collector_test.go b/prometheus/process_collector_test.go
index c7acb47..d59ad77 100644
--- a/prometheus/process_collector_test.go
+++ b/prometheus/process_collector_test.go
@@ -1,3 +1,5 @@
+// +build linux
+
 package prometheus
 
 import (
diff --git a/prometheus/promhttp/http.go b/prometheus/promhttp/http.go
index 8dc2603..0135737 100644
--- a/prometheus/promhttp/http.go
+++ b/prometheus/promhttp/http.go
@@ -302,7 +302,7 @@ func decorateWriter(request *http.Request, writer io.Writer, compressionDisabled
 	header := request.Header.Get(acceptEncodingHeader)
 	parts := strings.Split(header, ",")
 	for _, part := range parts {
-		part := strings.TrimSpace(part)
+		part = strings.TrimSpace(part)
 		if part == "gzip" || strings.HasPrefix(part, "gzip;") {
 			return gzip.NewWriter(writer), "gzip"
 		}
diff --git a/prometheus/promhttp/http_test.go b/prometheus/promhttp/http_test.go
index aeaa0b4..24d2f8c 100644
--- a/prometheus/promhttp/http_test.go
+++ b/prometheus/promhttp/http_test.go
@@ -121,7 +121,7 @@ the_count 0
 		t.Errorf("got HTTP status code %d, want %d", got, want)
 	}
 	if got := logBuf.String(); got != wantMsg {
-		t.Errorf("got log message:\n%s\nwant log mesage:\n%s\n", got, wantMsg)
+		t.Errorf("got log message:\n%s\nwant log message:\n%s\n", got, wantMsg)
 	}
 	if got := writer.Body.String(); got != wantErrorBody {
 		t.Errorf("got body:\n%s\nwant body:\n%s\n", got, wantErrorBody)
diff --git a/prometheus/push/push.go b/prometheus/push/push.go
index 02be52c..3721ff1 100644
--- a/prometheus/push/push.go
+++ b/prometheus/push/push.go
@@ -66,7 +66,7 @@ type Pusher struct {
 	username, password string
 }
 
-// New creates a new Pusher to push to the provided URL withe the provided job
+// New creates a new Pusher to push to the provided URL with the provided job
 // name. You can use just host:port or ip:port as url, in which case “http://”
 // is added automatically. Alternatively, include the schema in the
 // URL. However, do not include the “/metrics/jobs/…” part.
diff --git a/prometheus/registry.go b/prometheus/registry.go
index bee3703..f8efd1f 100644
--- a/prometheus/registry.go
+++ b/prometheus/registry.go
@@ -437,7 +437,7 @@ collectLoop:
 			))
 		default:
 			if goroutineBudget <= 0 || len(collectors) == 0 {
-				// All collectors are aleady being worked on or
+				// All collectors are already being worked on or
 				// we have already as many goroutines started as
 				// there are collectors. Just process metrics
 				// from now on.
diff --git a/prometheus/value.go b/prometheus/value.go
index 543b57c..9fb7eab 100644
--- a/prometheus/value.go
+++ b/prometheus/value.go
@@ -152,9 +152,7 @@ func makeLabelPairs(desc *Desc, labelValues []string) []*dto.LabelPair {
 			Value: proto.String(labelValues[i]),
 		})
 	}
-	for _, lp := range desc.constLabelPairs {
-		labelPairs = append(labelPairs, lp)
-	}
+	labelPairs = append(labelPairs, desc.constLabelPairs...)
 	sort.Sort(LabelPairSorter(labelPairs))
 	return labelPairs
 }