# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1491249606 -7200
# Node ID 510e76aa07f294921e3d369d6c1c35581ba5b36a
# Parent  6097bc0ef5ec4e08adf70187afd5ae79721c9860
Reposition parameters that are not explicitly specified if necessary.

diff -r 6097bc0ef5ec -r 510e76aa07f2 optimiser.py
--- a/optimiser.py	Mon Apr 03 02:24:46 2017 +0200
+++ b/optimiser.py	Mon Apr 03 22:00:06 2017 +0200
@@ -458,9 +458,23 @@
 
         # Allocate positions from 1 onwards, ignoring the context argument.
 
-        self.arg_locations = [set()] + get_allocated_locations(
-            self.importer.function_parameters, get_parameters_and_sizes,
-            self.existing_arg_locations[1:])
+        try:
+            self.arg_locations = [set()] + get_allocated_locations(
+                self.importer.function_parameters, get_parameters_and_sizes,
+                self.existing_arg_locations[1:])
+
+        # Uphold positioning conflicts only if the existing locations were
+        # explicitly specified.
+
+        except OptimiseError:
+            if self.parameter_locations_filename:
+                raise
+
+            # Otherwise, reposition parameters, causing the program to be
+            # regenerated.
+
+            self.arg_locations = [set()] + get_allocated_locations(
+                self.importer.function_parameters, get_parameters_and_sizes)
 
     def position_attributes(self):