diff --git a/README.md b/README.md
index 4c7f50f26b..388ef759d2 100644
--- a/README.md
+++ b/README.md
@@ -56,7 +56,7 @@ Prometheus will now be reachable at http://localhost:9090/.
 ### Building from source
 
 To build Prometheus from the source code yourself you need to have a working
-Go environment with [version 1.8 or greater installed](http://golang.org/doc/install).
+Go environment with [version 1.9 or greater installed](http://golang.org/doc/install).
 
 You can directly use the `go` tool to download and install the `prometheus`
 and `promtool` binaries into your `GOPATH`:
diff --git a/cmd/prometheus/main.go b/cmd/prometheus/main.go
index fc7951e5f2..ab3a862e2d 100644
--- a/cmd/prometheus/main.go
+++ b/cmd/prometheus/main.go
@@ -289,7 +289,7 @@ func main() {
 				}
 				files = append(files, fs...)
 			}
-			return ruleManager.Update(time.Duration(cfg.GlobalConfig.EvaluationInterval), cfg.RuleFiles)
+			return ruleManager.Update(time.Duration(cfg.GlobalConfig.EvaluationInterval), files)
 		},
 	}
 
diff --git a/discovery/file/file_test.go b/discovery/file/file_test.go
index 2305a0684a..5116ab9bc1 100644
--- a/discovery/file/file_test.go
+++ b/discovery/file/file_test.go
@@ -79,6 +79,7 @@ func testFileSD(t *testing.T, prefix, ext string, expect bool) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	defer newf.Close()
 
 	f, err := os.Open(filepath.Join(testDir, prefix+ext))
 	if err != nil {
@@ -90,14 +91,13 @@ func testFileSD(t *testing.T, prefix, ext string, expect bool) {
 		t.Fatal(err)
 	}
 
-	// File is written with the config so stop draining the discovery channel.
-	// It needs to be before the file closing so that fsnotify triggers a new loop of the discovery service.
+	// Test file is ready so stop draining the discovery channel.
+	// It contains two target groups.
 	close(fileReady)
 	<-drainReady
-	newf.Close()
+	newf.WriteString(" ") // One last meaningless write to trigger fsnotify and a new loop of the discovery service.
 
 	timeout := time.After(15 * time.Second)
-	// The files contain two target groups.
 retry:
 	for {
 		select {
@@ -105,7 +105,7 @@ retry:
 			if expect {
 				t.Fatalf("Expected new target group but got none")
 			} else {
-				// invalid type fsd should always broken down.
+				// Invalid type fsd should always break down.
 				break retry
 			}
 		case tgs := <-ch:
diff --git a/docs/querying/basics.md b/docs/querying/basics.md
index 062e2fe203..65798b74fe 100644
--- a/docs/querying/basics.md
+++ b/docs/querying/basics.md
@@ -116,6 +116,9 @@ The following expression selects all metrics that have a name starting with `job
 
     {__name__=~"job:.*"}
 
+All regular expressions in Prometheus use [RE2
+syntax](https://github.com/google/re2/wiki/Syntax).
+
 ### Range Vector Selectors
 
 Range vector literals work like instant vector literals, except that they
diff --git a/docs/querying/examples.md b/docs/querying/examples.md
index 589d6bbca6..5827ca5eb7 100644
--- a/docs/querying/examples.md
+++ b/docs/querying/examples.md
@@ -31,6 +31,9 @@ Note that this does a substring match, not a full string match:
 
     http_requests_total{job=~".*server"}
 
+All regular expressions in Prometheus use [RE2
+syntax](https://github.com/google/re2/wiki/Syntax).
+
 To select all HTTP status codes except 4xx ones, you could run:
 
     http_requests_total{status!~"4.."}
diff --git a/web/api/v1/api.go b/web/api/v1/api.go
index 474b10b438..462e492262 100644
--- a/web/api/v1/api.go
+++ b/web/api/v1/api.go
@@ -50,19 +50,19 @@ type status string
 
 const (
 	statusSuccess status = "success"
-	statusError          = "error"
+	statusError   status = "error"
 )
 
 type errorType string
 
 const (
 	errorNone        errorType = ""
-	errorTimeout               = "timeout"
-	errorCanceled              = "canceled"
-	errorExec                  = "execution"
-	errorBadData               = "bad_data"
-	errorInternal              = "internal"
-	errorUnavailable           = "unavailable"
+	errorTimeout     errorType = "timeout"
+	errorCanceled    errorType = "canceled"
+	errorExec        errorType = "execution"
+	errorBadData     errorType = "bad_data"
+	errorInternal    errorType = "internal"
+	errorUnavailable errorType = "unavailable"
 )
 
 var corsHeaders = map[string]string{