Make sure moved lines don't go into a fold

spec/editor-view-spec.coffee

@@ -2640,6 +2640,24 @@ describe "EditorView", ->
           expect(editor.getCursorBufferPosition()).toEqual [9, 0]
           expect(buffer.lineForRow(0)).toBe '  var sort = function(items) {'
           expect(buffer.lineForRow(9)).toBe 'var quicksort = function () {'
+          expect(editor.isFoldedAtBufferRow(0)).toBe true
+          expect(editor.isFoldedAtBufferRow(9)).toBe false
+
+      describe "when line below is empty and the line below that is folded", ->
+        it "moves the line to the empty line", ->
+          editor.setCursorBufferPosition([0, Infinity])
+          editor.insertText('\n')
+          editor.setCursorBufferPosition([0, 0])
+          editor.foldBufferRow(2)
+          editorView.trigger 'editor:move-line-down'
+
+          expect(editor.getCursorBufferPosition()).toEqual [1, 0]
+          expect(buffer.lineForRow(0)).toBe ''
+          expect(buffer.lineForRow(1)).toBe 'var quicksort = function () {'
+          expect(buffer.lineForRow(2)).toBe '  var sort = function(items) {'
+          expect(editor.isFoldedAtBufferRow(0)).toBe false
+          expect(editor.isFoldedAtBufferRow(1)).toBe false
+          expect(editor.isFoldedAtBufferRow(2)).toBe true
 
     describe "when the cursor is on the last line", ->
       it "does not move the line", ->

src/editor.coffee

@@ -670,8 +670,9 @@ class Editor extends Model
 
       # Move line around the fold that is directly below the selection
       insertDelta = 1
-      if foldRange = @languageMode.rowRangeForFoldAtBufferRow(selection.end.row + 1)
-        insertDelta += foldRange[1] - foldRange[0]
+      if @isFoldedAtBufferRow(selection.end.row + 1)
+        foldRange = @languageMode.rowRangeForFoldAtBufferRow(selection.end.row + 1)
+        insertDelta += foldRange[1] - foldRange[0] if foldRange?
 
       for row in rows
         screenRow = @screenPositionForBufferPosition([row]).row
@@ -694,6 +695,12 @@ class Editor extends Model
         insertPosition = Point.min([startRow + insertDelta], @buffer.getEofPosition())
         if insertPosition.row is @buffer.getLastRow() and insertPosition.column > 0
           lines = "\n#{lines}"
+
+        # Make sure the inserted text doesn't go into an existing fold
+        if @isFoldedAtBufferRow(insertPosition.row)
+          @destroyFoldsContainingBufferRow(insertPosition.row)
+          foldedRows.push(insertPosition.row + startRow - endRow + 1)
+
         @buffer.insert(insertPosition, lines)
 
       @foldBufferRow(foldedRow) for foldedRow in foldedRows