+CAUTION: line numbers are stored as unsigned ptrint! You need
+ to cast them (to s4) in order to test <0, etc.
+ (The ptrint values are created by casting a s4 to ptrint.)
+
+Nesting
+-------
+
+For nested inline bodies, the entries of the inner inline body are inserted
+between the entries of the outer inline body just the same as at the top level.
+