diff --git a/inform7/Figures/timings-diagnostics.txt b/inform7/Figures/timings-diagnostics.txt
index d91f0e2cb1..ff703b14ed 100644
--- a/inform7/Figures/timings-diagnostics.txt
+++ b/inform7/Figures/timings-diagnostics.txt
@@ -1,27 +1,28 @@
 100.0% in inform7 run
-     68.1% in compilation to Inter
-         47.8% in //Sequence::undertake_queued_tasks//
-          4.5% in //MajorNodes::pre_pass//
-          3.2% in //MajorNodes::pass_1//
+     68.3% in compilation to Inter
+         47.9% in //Sequence::undertake_queued_tasks//
+          4.6% in //MajorNodes::pre_pass//
+          3.3% in //MajorNodes::pass_1//
           2.3% in //RTPhrasebook::compile_entries//
           1.8% in //ImperativeDefinitions::assess_all//
           1.5% in //RTKindConstructors::compile//
           1.0% in //Sequence::lint_inter//
           0.5% in //MajorNodes::pass_2//
-          0.5% in //Sequence::undertake_queued_tasks//
           0.5% in //World::stage_V//
           0.4% in //ImperativeDefinitions::compile_first_block//
           0.4% in //Sequence::undertake_queued_tasks//
+          0.4% in //Sequence::undertake_queued_tasks//
           0.2% in //CompletionModule::compile//
           0.2% in //RTKindConstructors::compile_permissions//
           0.1% in //InferenceSubjects::emit_all//
           0.1% in //Task::make_built_in_kind_constructors//
+          0.1% in //Understand::traverse//
           0.1% in //World::stages_II_and_III//
           2.1% not specifically accounted for
-     29.3% in running Inter pipeline
-         10.0% in step 14/15: generate inform6 -> auto.inf
-          8.3% in step 5/15: load-binary-kits
-          6.5% in step 6/15: make-synoptic-module
+     29.0% in running Inter pipeline
+         10.1% in step 14/15: generate inform6 -> auto.inf
+          7.6% in step 5/15: load-binary-kits
+          6.6% in step 6/15: make-synoptic-module
           1.5% in step 9/15: make-identifiers-unique
           0.4% in step 12/15: eliminate-redundant-operations
           0.4% in step 4/15: compile-splats
@@ -31,6 +32,6 @@
           0.1% in step 10/15: reconcile-verbs
           0.1% in step 2/15: parse-insertions
           0.1% in step 3/15: resolve-conditional-compilation
-          0.5% not specifically accounted for
+          0.7% not specifically accounted for
       2.2% in supervisor
-      0.3% not specifically accounted for
+      0.4% not specifically accounted for
diff --git a/inform7/Internal/Inter/WorldModelKit/Sections/WorldModel.i6t b/inform7/Internal/Inter/WorldModelKit/Sections/WorldModel.i6t
index c5bc39cf78..707c511bd3 100644
--- a/inform7/Internal/Inter/WorldModelKit/Sections/WorldModel.i6t
+++ b/inform7/Internal/Inter/WorldModelKit/Sections/WorldModel.i6t
@@ -653,6 +653,7 @@ doors.
 
 =
 [ TestAdjacency R1 R2 i row;
+	if ((R1 == nothing) || (R2 == nothing)) rfalse;
 	if (R1 ofclass K9_region) RunTimeProblem(RTP_REGIONSNOTADJACENT, R1);
 	else if (R2 ofclass K9_region) RunTimeProblem(RTP_REGIONSNOTADJACENT, R2);
 	row = (R1.IK1_Count)*No_Directions;
diff --git a/inform7/Tests/Test Makes/Eg4-C/textual.txt b/inform7/Tests/Test Makes/Eg4-C/textual.txt
index 2063d06bd4..2becb1c425 100644
--- a/inform7/Tests/Test Makes/Eg4-C/textual.txt	
+++ b/inform7/Tests/Test Makes/Eg4-C/textual.txt	
@@ -29143,9 +29143,9 @@ package main _plain
 					package phrasebook_entry7 _phrasebook_entry
 						constant (text) ^text = "<p class=\"tightin2\"><a href=\"#\" onclick=\"showExtra('extra191', 'plus191'); return false;\"><img border=0 id=\"plus191\" src=inform:/doc_images/extra.png></a>&nbsp;number of filled rows in<span style='color:#808080'>/from</span> (<span style='color:#4040ff'>table name</span>) ... <i>number</i></p>\n<div id=\"extra191\" style=\"display: none;\">\n    <p class=\"in3\"><table width=\"100%\" cellpadding=\"0\" cellspacing=\"0\" border=\"0\" style=\"background-color: #e0e0e0\">\n        <tr>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/tl_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n            <td>\n\n            </td>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/tr_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n        </tr>\n        <tr>\n            <td width=\"8\">\n\n            </td>\n            <td>\n                <p><a href=\"javascript:pasteCode('number of filled rows in')\"><img border=0 src=inform:/doc_images/paste.png></a>&nbsp;number of filled rows in<span style='color:#808080'>/from</span> (<span style='color:#4040ff'>table name</span>) ... <i>number</i></p>\n\n\n                    <p>    This phrase produces the number of rows in the given table which are not entirely blank (that is, at least one column has a value in this row).</p>\n\n                <p><b>See</b> &nbsp;<a href=inform:/doc255.html><img border=0 src=inform:/doc_images/help.png></a>&nbsp;16.10. 16.10. Adding and removing rows</p>\n                <p><b>Kind:</b> phrase table name -> number</p>\n\n            </td>\n            <td width=\"8\">\n\n            </td>\n        </tr>\n        <tr>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/bl_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n            <td>\n\n            </td>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/br_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n        </tr>\n    </table>\n    </p>\n</div>\n"
 					package phrasebook_entry8 _phrasebook_entry
-						constant (text) ^text = "<p class=\"tightin2\"><a href=\"#\" onclick=\"showExtra('extra192', 'plus192'); return false;\"><img border=0 id=\"plus192\" src=inform:/doc_images/extra.png></a>&nbsp;<i>if</i> there is (<span style='color:#E00060'>a table entry</span>)<i>:</i></p>\n<div id=\"extra192\" style=\"display: none;\">\n    <p class=\"in3\"><table width=\"100%\" cellpadding=\"0\" cellspacing=\"0\" border=\"0\" style=\"background-color: #e0e0e0\">\n        <tr>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/tl_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n            <td>\n\n            </td>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/tr_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n        </tr>\n        <tr>\n            <td width=\"8\">\n\n            </td>\n            <td>\n                <p><a href=\"javascript:pasteCode('there is')\"><img border=0 src=inform:/doc_images/paste.png></a>&nbsp;<i>if</i> there is (<span style='color:#E00060'>a table entry</span>)<i>:</i></p>\n\n\n                    <p>    This condition is true if the entry referred to exists, that is, that is, the space for it in the table is not blank. Examples:</p>\n                    <!--START CODE \"c5105\"-->\n                    <blockquote class=\"code\"><p class=\"quoted\"><a id=\"c5105\"></a>if there is a symbol corresponding to an atomic number of 30 in the Table of Standard Elements ...\n                    <br>\n                    if there is an atomic number in row 2 of the Table of Standard Elements ...\n                    </p>\n                    </blockquote>\n                    <!--END CODE-->\n\n                <p><b>See</b> &nbsp;<a href=inform:/doc252.html><img border=0 src=inform:/doc_images/help.png></a>&nbsp;16.7. 16.7. Blank entries</p>\n                <p><b>Kind:</b> phrase value -> truth state</p>\n\n            </td>\n            <td width=\"8\">\n\n            </td>\n        </tr>\n        <tr>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/bl_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n            <td>\n\n            </td>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/br_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n        </tr>\n    </table>\n    </p>\n</div>\n"
+						constant (text) ^text = "<p class=\"tightin2\"><a href=\"#\" onclick=\"showExtra('extra192', 'plus192'); return false;\"><img border=0 id=\"plus192\" src=inform:/doc_images/extra.png></a>&nbsp;<i>if</i> there is (<span style='color:#E00060'>a table entry</span>)<i>:</i></p>\n<div id=\"extra192\" style=\"display: none;\">\n    <p class=\"in3\"><table width=\"100%\" cellpadding=\"0\" cellspacing=\"0\" border=\"0\" style=\"background-color: #e0e0e0\">\n        <tr>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/tl_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n            <td>\n\n            </td>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/tr_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n        </tr>\n        <tr>\n            <td width=\"8\">\n\n            </td>\n            <td>\n                <p><a href=\"javascript:pasteCode('there is')\"><img border=0 src=inform:/doc_images/paste.png></a>&nbsp;<i>if</i> there is (<span style='color:#E00060'>a table entry</span>)<i>:</i></p>\n\n\n                    <p>    This condition is true if the entry referred to exists, that is, that is, the space for it in the table is not blank. Examples:</p>\n                    <!--START CODE \"c5105\"-->\n                    <blockquote class=\"code\"><p class=\"quoted\"><a id=\"c5105\"></a>if there is a symbol corresponding to an atomic number of 30 in the Table of Selected Elements ...\n                    <br>\n                    if there is an atomic number in row 2 of the Table of Selected Elements ...\n                    </p>\n                    </blockquote>\n                    <!--END CODE-->\n\n                <p><b>See</b> &nbsp;<a href=inform:/doc252.html><img border=0 src=inform:/doc_images/help.png></a>&nbsp;16.7. 16.7. Blank entries</p>\n                <p><b>Kind:</b> phrase value -> truth state</p>\n\n            </td>\n            <td width=\"8\">\n\n            </td>\n        </tr>\n        <tr>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/bl_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n            <td>\n\n            </td>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/br_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n        </tr>\n    </table>\n    </p>\n</div>\n"
 					package phrasebook_entry9 _phrasebook_entry
-						constant (text) ^text = "<p class=\"tightin2\"><a href=\"#\" onclick=\"showExtra('extra193', 'plus193'); return false;\"><img border=0 id=\"plus193\" src=inform:/doc_images/extra.png></a>&nbsp;<i>if</i> there is no (<span style='color:#E00060'>a table entry</span>)<i>:</i></p>\n<div id=\"extra193\" style=\"display: none;\">\n    <p class=\"in3\"><table width=\"100%\" cellpadding=\"0\" cellspacing=\"0\" border=\"0\" style=\"background-color: #e0e0e0\">\n        <tr>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/tl_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n            <td>\n\n            </td>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/tr_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n        </tr>\n        <tr>\n            <td width=\"8\">\n\n            </td>\n            <td>\n                <p><a href=\"javascript:pasteCode('there is no')\"><img border=0 src=inform:/doc_images/paste.png></a>&nbsp;<i>if</i> there is no (<span style='color:#E00060'>a table entry</span>)<i>:</i></p>\n\n\n                    <p>    This condition is true if the entry referred to does not exist, that is, the space for it in the table is blank. Examples:</p>\n                    <!--START CODE \"c5106\"-->\n                    <blockquote class=\"code\"><p class=\"quoted\"><a id=\"c5106\"></a>if there is no symbol corresponding to an atomic number of 30 in the Table of Standard Elements ...\n                    <br>\n                    if there is no atomic number in row 2 of the Table of Standard Elements ...\n                    </p>\n                    </blockquote>\n                    <!--END CODE-->\n\n                <p><b>See</b> &nbsp;<a href=inform:/doc252.html><img border=0 src=inform:/doc_images/help.png></a>&nbsp;16.7. 16.7. Blank entries</p>\n                <p><b>Kind:</b> phrase value -> truth state</p>\n\n            </td>\n            <td width=\"8\">\n\n            </td>\n        </tr>\n        <tr>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/bl_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n            <td>\n\n            </td>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/br_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n        </tr>\n    </table>\n    </p>\n</div>\n"
+						constant (text) ^text = "<p class=\"tightin2\"><a href=\"#\" onclick=\"showExtra('extra193', 'plus193'); return false;\"><img border=0 id=\"plus193\" src=inform:/doc_images/extra.png></a>&nbsp;<i>if</i> there is no (<span style='color:#E00060'>a table entry</span>)<i>:</i></p>\n<div id=\"extra193\" style=\"display: none;\">\n    <p class=\"in3\"><table width=\"100%\" cellpadding=\"0\" cellspacing=\"0\" border=\"0\" style=\"background-color: #e0e0e0\">\n        <tr>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/tl_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n            <td>\n\n            </td>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/tr_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n        </tr>\n        <tr>\n            <td width=\"8\">\n\n            </td>\n            <td>\n                <p><a href=\"javascript:pasteCode('there is no')\"><img border=0 src=inform:/doc_images/paste.png></a>&nbsp;<i>if</i> there is no (<span style='color:#E00060'>a table entry</span>)<i>:</i></p>\n\n\n                    <p>    This condition is true if the entry referred to does not exist, that is, the space for it in the table is blank. Examples:</p>\n                    <!--START CODE \"c5106\"-->\n                    <blockquote class=\"code\"><p class=\"quoted\"><a id=\"c5106\"></a>if there is no symbol corresponding to an atomic number of 30 in the Table of Selected Elements ...\n                    <br>\n                    if there is no atomic number in row 2 of the Table of Selected Elements ...\n                    </p>\n                    </blockquote>\n                    <!--END CODE-->\n\n                <p><b>See</b> &nbsp;<a href=inform:/doc252.html><img border=0 src=inform:/doc_images/help.png></a>&nbsp;16.7. 16.7. Blank entries</p>\n                <p><b>Kind:</b> phrase value -> truth state</p>\n\n            </td>\n            <td width=\"8\">\n\n            </td>\n        </tr>\n        <tr>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/bl_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n            <td>\n\n            </td>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/br_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n        </tr>\n    </table>\n    </p>\n</div>\n"
 					package phrasebook_entry10 _phrasebook_entry
 						constant (text) ^text = "<p class=\"tightin2\"><a href=\"#\" onclick=\"showExtra('extra194', 'plus194'); return false;\"><img border=0 id=\"plus194\" src=inform:/doc_images/extra.png></a>&nbsp;blank out (<span style='color:#E00060'>a table entry</span>)</p>\n<div id=\"extra194\" style=\"display: none;\">\n    <p class=\"in3\"><table width=\"100%\" cellpadding=\"0\" cellspacing=\"0\" border=\"0\" style=\"background-color: #e0e0e0\">\n        <tr>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/tl_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n            <td>\n\n            </td>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/tr_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n        </tr>\n        <tr>\n            <td width=\"8\">\n\n            </td>\n            <td>\n                <p><a href=\"javascript:pasteCode('blank out')\"><img border=0 src=inform:/doc_images/paste.png></a>&nbsp;blank out (<span style='color:#E00060'>a table entry</span>)</p>\n\n\n                    <p>    This phrase replaces the entry referred to with a blank, erasing any value previously stored there. Example:</p>\n                    <!--START CODE \"c5141\"-->\n                    <blockquote class=\"code\"><p class=\"quoted\"><a id=\"c5141\"></a>choose row 1 in the Table of Fish Habitats;\n                    <br>\n                    blank out the salinity entry;\n                    </p>\n                    </blockquote>\n                    <!--END CODE-->\n\n                <p><b>See</b> &nbsp;<a href=inform:/doc255.html><img border=0 src=inform:/doc_images/help.png></a>&nbsp;16.10. 16.10. Adding and removing rows</p>\n                <p><b>Kind:</b> phrase value -> nothing</p>\n\n            </td>\n            <td width=\"8\">\n\n            </td>\n        </tr>\n        <tr>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/bl_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n            <td>\n\n            </td>\n            <td width=\"8\">\n                <img src=\"inform:/bg_images/br_corner_e0e0e0.gif\" width=\"8\" height=\"8\" border=\"0\" alt=\"...\">\n            </td>\n        </tr>\n    </table>\n    </p>\n</div>\n"
 					package phrasebook_entry11 _phrasebook_entry