Index: cross-project-tests/debuginfo-tests/dexter/Commands.md
===================================================================
--- cross-project-tests/debuginfo-tests/dexter/Commands.md
+++ cross-project-tests/debuginfo-tests/dexter/Commands.md
@@ -170,10 +170,12 @@
 
 ---
 ## DexUnreachable
-    DexUnreachable()
+    DexUnreachable([, **from_line=1][,**to_line=Max][,**on_line])
 
 ### Description
-Expect the source line this is found on will never be stepped on to.
+Expect the source line this is found on will never be stepped on to. If either
+'on_line' or both 'from_line' and 'to_line' are specified, checks that the
+specified line(s) are not stepped on.
 
 ### Heuristic
 [TODO]
Index: cross-project-tests/debuginfo-tests/dexter/dex/command/commands/DexUnreachable.py
===================================================================
--- cross-project-tests/debuginfo-tests/dexter/dex/command/commands/DexUnreachable.py
+++ cross-project-tests/debuginfo-tests/dexter/dex/command/commands/DexUnreachable.py
@@ -18,7 +18,21 @@
     See Commands.md for more info.
     """
 
-    def __init(self):
+    def __init__(self, *args, **kwargs):
+        if len(args) != 0:
+            raise TypeError("DexUnreachable takes no positional arguments")
+        if 'on_line' in kwargs:
+            on_line = kwargs.pop('on_line')
+            self._from_line = on_line
+            self._to_line = on_line
+        elif 'from_line' in kwargs and 'to_line' in kwargs:
+            self._from_line = kwargs.pop('from_line')
+            self._to_line = kwargs.pop('to_line')
+        elif 'from_line' in kwargs or 'to_line' in kwargs:
+            raise TypeError("Must provide both from_line and to_line to DexUnreachable")
+
+        if len(kwargs) > 0:
+            raise TypeError("Unexpected kwargs {}".format(kwargs.keys()))
         super(DexUnreachable, self).__init__()
         pass
 
Index: cross-project-tests/debuginfo-tests/dexter/dex/debugger/DebuggerControllers/ControllerHelpers.py
===================================================================
--- cross-project-tests/debuginfo-tests/dexter/dex/debugger/DebuggerControllers/ControllerHelpers.py
+++ cross-project-tests/debuginfo-tests/dexter/dex/debugger/DebuggerControllers/ControllerHelpers.py
@@ -18,6 +18,15 @@
     return any(os.path.samefile(step_info.current_location.path, f) \
                for f in source_files)
 
+def have_hit_line(watch, loc):
+  if hasattr(watch, '_on_line'):
+    return watch._on_line == loc.lineno
+  elif hasattr(watch, '_from_line'):
+    return watch._from_line <= loc.lineno and watch._to_line >= loc.lineno
+  elif watch.lineno == loc.lineno:
+    return True
+  return False
+
 def update_step_watches(step_info, watches, commands):
     watch_cmds = ['DexUnreachable', 'DexExpectStepOrder']
     towatch = chain.from_iterable(commands[x]
@@ -30,7 +39,7 @@
             if (loc.path != None
                     and os.path.exists(loc.path)
                     and os.path.samefile(watch.path, loc.path)
-                    and watch.lineno == loc.lineno):
+                    and have_hit_line(watch, loc)):
                 result = watch.eval(step_info)
                 step_info.watches.update(result)
                 break
Index: cross-project-tests/debuginfo-tests/dexter/feature_tests/commands/penalty/unreachable_line_range.cpp
===================================================================
--- /dev/null
+++ cross-project-tests/debuginfo-tests/dexter/feature_tests/commands/penalty/unreachable_line_range.cpp
@@ -0,0 +1,17 @@
+// Purpose:
+//      Check that \DexUnreachable correctly applies a penalty if the command
+//      line is stepped on.
+//
+// UNSUPPORTED: system-darwin
+//
+//
+// RUN: not %dexter_regression_test -- %s | FileCheck %s
+// CHECK: unreachable_line_range.cpp:
+
+int
+main()
+{ // DexLabel('begin')
+  return 1;
+} // DexLabel('end')
+
+// DexUnreachable(from_line=ref('begin'), to_line=ref('end'))
Index: cross-project-tests/debuginfo-tests/dexter/feature_tests/commands/penalty/unreachable_on_line.cpp
===================================================================
--- /dev/null
+++ cross-project-tests/debuginfo-tests/dexter/feature_tests/commands/penalty/unreachable_on_line.cpp
@@ -0,0 +1,17 @@
+// Purpose:
+//      Check that \DexUnreachable correctly applies a penalty if the command
+//      line is stepped on.
+//
+// UNSUPPORTED: system-darwin
+//
+//
+// RUN: not %dexter_regression_test -- %s | FileCheck %s
+// CHECK: unreachable_on_line.cpp:
+
+int
+main()
+{
+  return 1;  // DexLabel('this_one')
+}
+
+// DexUnreachable(on_line=ref('this_one'))
Index: cross-project-tests/debuginfo-tests/dexter/feature_tests/commands/perfect/unreachable_not_cmd_lineno.cpp
===================================================================
--- /dev/null
+++ cross-project-tests/debuginfo-tests/dexter/feature_tests/commands/perfect/unreachable_not_cmd_lineno.cpp
@@ -0,0 +1,17 @@
+// Purpose:
+//    Check that \DexUnreachable doesn't trigger on the line it's specified
+//    on, if it has a specifier indicating which lines should be unreachable.
+//
+// UNSUPPORTED: system-darwin
+//
+// RUN: %dexter_regression_test -- %s | FileCheck %s
+// CHECK: unreachable_not_cmd_lineno.cpp:
+
+int main(int argc, char **argv)
+{
+  if (argc != 1)
+    return 1; // DexLabel('this_one')
+  else
+    return 0; // DexUnreachable(on_line=ref('this_one')) DexUnreachable(from_line=ref('this_one'), to_line=ref('this_one'))
+}
+
Index: cross-project-tests/debuginfo-tests/dexter/feature_tests/commands/perfect/unreachable_on_line.cpp
===================================================================
--- /dev/null
+++ cross-project-tests/debuginfo-tests/dexter/feature_tests/commands/perfect/unreachable_on_line.cpp
@@ -0,0 +1,18 @@
+// Purpose:
+//    Check that \DexUnreachable has no effect if the command line is never
+//    stepped on.
+//
+// UNSUPPORTED: system-darwin
+//
+// RUN: %dexter_regression_test -- %s | FileCheck %s
+// CHECK: unreachable_on_line.cpp:
+
+int main()
+{
+  return 0;
+  return 1; // DexLabel('this_one')
+}
+
+
+// DexUnreachable(on_line=ref('this_one'))
+// DexUnreachable(from_line=ref('this_one'), to_line=ref('this_one'))