Remove some ambiguities in parsing

src/Lib/Parser.newt

@@ -314,7 +314,7 @@ lamExpr = do
 caseAlt : Parser RCaseAlt
 caseAlt = do
   pure MkUnit
-  pat <- typeExpr
+  pat <- term
   t <- optional (keyword "=>" >> term)
   pure $ MkAlt pat t
 
@@ -364,6 +364,7 @@ doCaseLet = do
   keyword "="
   sc <- typeExpr
   alts <- startBlock $ manySame $ symbol "|" *> caseAlt
+  -- REVIEW why am I collecting the rest here?
   bodyFC <- getPos
   body <- RDo <$> getPos <*> someSame doStmt
   pure $ DoExpr fc (RCase fc sc Nothing (MkAlt pat (Just body) :: alts))
@@ -457,9 +458,9 @@ ibind = do
   symbol "{"
   quant <- quantity
   names <- (some (addPos varname))
-  ty <- optional (symbol ":" *> typeExpr)
+  ty <- symbol ":" *> typeExpr
   symbol "}"
-  pure $ map (makeBind quant ty) names
+  pure $ map (makeBind quant (Just ty)) names
   where
     makeBind : Quant → Maybe Raw → FC × String → BindInfo × Raw
     makeBind quant ty (pos, name) = (BI pos name Implicit quant, fromMaybe (RImplicit pos) ty)

src/Prelude.newt

@@ -146,7 +146,7 @@ class Functor (m : U → U) where
   map : ∀ a b. (a → b) → m a → m b
 
 infixr 4 _<$>_ _<$_
-_<$>_ : ∀ f. {{Functor f}} {0 a b} → (a → b) → f a → f b
+_<$>_ : ∀ f. {{Functor f}} {0 a b : _} → (a → b) → f a → f b
 f <$> ma = map f ma
 
 _<$_ : ∀ f a b. {{Functor f}} → b → f a → f b
@@ -214,7 +214,7 @@ instance Applicative Maybe where
 
 infixr 2 _<|>_
 class Alternative (m : U → U) where
-  _<|>_ : {0 a} → m a → m a → m a
+  _<|>_ : ∀ a. m a → m a → m a
 
 instance Alternative Maybe where
   Nothing <|> x = x
@@ -368,12 +368,12 @@ instance Monad List where
 
 
 -- This is traverse, but we haven't defined Traversable yet
-mapA : ∀ m. {{Applicative m}} {0 a b} → (a → m b) → List a → m (List b)
+mapA : ∀ m. {{Applicative m}} {0 a b : _} → (a → m b) → List a → m (List b)
 mapA f Nil = return Nil
 mapA f (x :: xs) = return _::_ <*> f x <*> mapA f xs
 
 
-mapM : ∀ m. {{Monad m}} {0 a b} → (a → m b) → List a → m (List b)
+mapM : ∀ m. {{Monad m}} {0 a b : _} → (a → m b) → List a → m (List b)
 mapM f Nil = pure Nil
 mapM f (x :: xs) = do
   b <- f x
@@ -433,6 +433,9 @@ pfunc pack : List Char → String := `(cs) => {
 }
 `
 
+-- FIXME this no longer works with numeric tags
+-- we could take the best of both worlds and have a debug flag to add extra information
+-- but also we could derive Show...
 pfunc debugStr uses (natToInt listToArray) : ∀ a. a → String := `(_, obj) => {
   const go = (obj) => {
     if (obj === null) return "_"