Slightly better hashing function for interfaces

The previous one would have given the same result if swapping a name and
a type... oops!

CHANGELOG.md

@@ -1,3 +1,10 @@
+# New in next version
+
+## Tool updates
++ Modules no longer require building if imports have changed but all
+  interfaces (i.e. types for names declared `export` and definitions of names
+  declared `public export`) are unchanged.
+
 # New in 1.3.1
 
 ## Tool updates

src/Idris/IBC.hs

@@ -257,19 +257,20 @@ qhash :: Int -> String -> Int
 qhash hash [] = abs hash `mod` 0xffffffff
 qhash hash (x:xs) = qhash (hash * 33 + fromIntegral (fromEnum x)) xs
 
-hashTerm :: Term -> Int
-hashTerm t = qhash 5381 (show t)
+hashTerm :: Int -> Term -> Int
+hashTerm i t = qhash (i * 5381) (show t)
 
-hashName :: Name -> Int
-hashName n = qhash 5381 (show n)
+hashName :: Int -> Name -> Int
+hashName i n = qhash (i * 5381) (show n)
 
 calculateHash :: IState -> IBCFile -> Int
 calculateHash ist f
     = let acc = L.filter exported (ibc_access f) in
           mkHashFrom (map fst acc) (getDefs acc)
   where
     mkHashFrom :: [Name] -> [Term] -> Int
-    mkHashFrom ns tms = sum (map hashName ns) + sum (map hashTerm tms)
+    mkHashFrom ns tms = sum (L.zipWith hashName [1..] ns) + 
+                        sum (L.zipWith hashTerm [1..] tms)
 
     exported (_, Public) = True
     exported (_, Frozen) = True

src/Idris/Parser.hs

@@ -1683,8 +1683,9 @@ loadSource lidr f toline
                          (sort impHashes /= sort (mapMaybe id newHashes))
 
           if not needLoad
-             then iReport 1 $ "Loading " ++ f
+             then pure ()
              else do
+              iReport 1 $ "Type checking " ++ f
               mapM_ (\ (re, f, ns, nfc) ->
                            do fp <- findImport ids ibcsd f
                               case fp of
@@ -1765,7 +1766,6 @@ loadSource lidr f toline
               logLvl 10 (show (toAlist (idris_implicits i)))
               logLvl 3 (show (idris_infixes i))
               -- Now add all the declarations to the context
-              iReport 1 $ "Type checking " ++ f
               -- we totality check after every Mutual block, so if
               -- anything is a single definition, wrap it in a
               -- mutual block on its own