# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1489338248 -3600
# Node ID 07bc2bf9377f85e707403b91c2cde845c2b27535
# Parent  8453ca48a9802964db68ee2e1c42e2e602324954
Propagate return values, making use of them in deduction.

diff -r 8453ca48a980 -r 07bc2bf9377f deducer.py
--- a/deducer.py	Sun Mar 12 18:03:25 2017 +0100
+++ b/deducer.py	Sun Mar 12 18:04:08 2017 +0100
@@ -1775,8 +1775,13 @@
 
         "Convert 'ref' to a provider appropriate to its invocation result."
 
-        if ref and ref.has_kind("<class>"):
-            return ref
+        if ref:
+            if ref.has_kind("<class>"):
+                return ref
+            elif ref.has_kind("<function>"):
+                refs = self.importer.all_return_values.get(ref.get_origin())
+                if refs and len(refs) == 1:
+                    return first(refs)
 
         return Reference("<var>")
 
@@ -1793,8 +1798,13 @@
 
         "Convert 'ref' to its invocation result."
 
-        if ref and ref.has_kind("<class>"):
-            return ref.instance_of()
+        if ref:
+            if ref.has_kind("<class>"):
+                return ref.instance_of()
+            elif ref.has_kind("<function>"):
+                refs = self.importer.all_return_values.get(ref.get_origin())
+                if refs and len(refs) == 1:
+                    return first(refs)
 
         return Reference("<var>")
 
diff -r 8453ca48a980 -r 07bc2bf9377f importer.py
--- a/importer.py	Sun Mar 12 18:03:25 2017 +0100
+++ b/importer.py	Sun Mar 12 18:04:08 2017 +0100
@@ -116,6 +116,10 @@
         self.all_constants = {}
         self.all_constant_values = {}
 
+        # Return values.
+
+        self.all_return_values = {}
+
         self.make_cache()
 
     def give_warning(self, name):
diff -r 8453ca48a980 -r 07bc2bf9377f modules.py
--- a/modules.py	Sun Mar 12 18:03:25 2017 +0100
+++ b/modules.py	Sun Mar 12 18:04:08 2017 +0100
@@ -115,6 +115,7 @@
         self.propagate_name_references()
         self.propagate_attr_accesses()
         self.propagate_constants()
+        self.propagate_return_values()
 
     def unpropagate(self):
 
@@ -151,6 +152,7 @@
         remove_items(self.importer.all_attr_access_modifiers, self.attr_access_modifiers)
         remove_items(self.importer.all_constants, self.constants)
         remove_items(self.importer.all_constant_values, self.constant_values)
+        remove_items(self.importer.all_return_values, self.return_values)
 
         # Remove this module's objects from the importer. Objects are
         # automatically propagated when defined.
@@ -220,6 +222,12 @@
             self.importer.all_instance_attrs[name] = self.instance_attrs.get(name) or {}
             self.importer.all_instance_attr_constants[name] = self.instance_attr_constants.get(name) or {}
 
+    def propagate_return_values(self):
+
+        "Propagate return values for the module."
+
+        self.importer.all_return_values.update(self.return_values)
+
     def set_object(self, name, value=None):
 
         "Set an object with the given 'name' and the given 'value'."