If the user attempts to switch tab stops while the cursor is not *on* a tab stop, the snippet is terminated

spec/extensions/snippets-spec.coffee

@@ -93,6 +93,28 @@ describe "Snippets extension", ->
             expect(buffer.lineForRow(0)).toBe 'go here first and then here second'
             expect(editor.getSelectedBufferRange()).toEqual [[0, 8], [0, 13]]
 
+        describe "when the cursor is moved beyond the bounds of a tab stop", ->
+          fit "terminates the snippet on the next tab", ->
+            editor.setCursorScreenPosition([2, 0])
+            editor.insertText('t2')
+            editor.trigger keydownEvent('tab', target: editor[0])
+
+            editor.moveCursorRight()
+            editor.trigger keydownEvent('tab', target: editor[0])
+            expect(buffer.lineForRow(3)).toBe "go here first:()  "
+            expect(editor.getCursorBufferPosition()).toEqual [3, 18]
+
+            # test we can terminate with shift-tab
+            editor.setCursorScreenPosition([4, 0])
+            editor.insertText('t2')
+            editor.trigger keydownEvent('tab', target: editor[0])
+            editor.trigger keydownEvent('tab', target: editor[0])
+
+            editor.moveCursorRight()
+            editor.trigger keydownEvent('tab', shiftKey: true, target: editor[0])
+            expect(editor.getCursorBufferPosition()).toEqual [4, 15]
+
+
       describe "when a the start of the snippet is indented", ->
         it "indents the subsequent lines of the snippet to be even with the start of the first line", ->
           editor.setCursorScreenPosition([2, Infinity])

src/app/anchor-range.coffee

@@ -16,6 +16,9 @@ class AnchorRange
   getScreenRange: ->
     new Range(@startAnchor.getScreenPosition(), @endAnchor.getScreenPosition())
 
+  containsBufferPosition: (bufferPosition) ->
+    @getBufferRange().containsPoint(bufferPosition)
+
   destroy: ->
     @startAnchor.destroy()
     @endAnchor.destroy()

src/extensions/snippets/snippets.coffee

@@ -39,6 +39,7 @@ module.exports =
 class SnippetsSession
   tabStopAnchorRanges: null
   constructor: (@editSession, @snippetsByExtension) ->
+    @editSession.on 'move-cursor', => @terminateIfCursorIsOutsideTabStops()
 
   expandSnippet: ->
     return unless snippets = @snippetsByExtension[@editSession.buffer.getExtension()]
@@ -67,7 +68,7 @@ class SnippetsSession
         @editSession.buffer.insert([row, 0], initialIndent)
 
   goToNextTabStop: ->
-    return false unless @tabStopAnchorRanges
+    return false unless @ensureValidTabStops()
     nextIndex = @tabStopIndex + 1
     if nextIndex < @tabStopAnchorRanges.length
       @setTabStopIndex(nextIndex)
@@ -77,12 +78,24 @@ class SnippetsSession
       false
 
   goToPreviousTabStop: ->
-    return false unless @tabStopAnchorRanges
+    return false unless @ensureValidTabStops()
     @setTabStopIndex(@tabStopIndex - 1) if @tabStopIndex > 0
     true
 
+  ensureValidTabStops: ->
+    @tabStopAnchorRanges? and @terminateIfCursorIsOutsideTabStops()
+
   setTabStopIndex: (@tabStopIndex) ->
     @editSession.setSelectedBufferRange(@tabStopAnchorRanges[@tabStopIndex].getBufferRange())
 
+  terminateIfCursorIsOutsideTabStops: ->
+    return unless @tabStopAnchorRanges
+    position = @editSession.getCursorBufferPosition()
+    for anchorRange in @tabStopAnchorRanges
+      return true if anchorRange.containsBufferPosition(position)
+    @terminateActiveSnippet()
+    false
+
   terminateActiveSnippet: ->
-    anchor.destroy() for anchor in @tabStopAnchorRanges
+    anchorRange.destroy() for anchorRange in @tabStopAnchorRanges
+    @tabStopAnchorRanges = null