Pull type querying into its own (file and) typeclass.

Why?  Because checking types is restricted to rename-only
substitutions (which the checker itself generates), but we want to be
able to query types through a more meaningful substitution, such as
the one carried by SimplifyM.

Also, specializing the implementation to just querying lets us worry
less about relying on laziness (in the HardFail monad) for performance.

The ultimate purpose is to be able to (efficiently) query types in the
input space of a pass (without having to subtitute the whole
atom/expr/block first).

This change reduces allocations on the kernel regression example by 6%,
and improves runtime by about 2.5%.

Author: axch

dex.cabal

@@ -80,6 +80,7 @@ library
                      , Types.Imp
                      , Types.Primitives
                      , Types.Source
+                     , QueryType
                      , Util
   if flag(live)
     exposed-modules:   Actor

src/lib/Algebra.hs

@@ -25,7 +25,7 @@ import Data.Coerce
 import Builder hiding (sub, add)
 import Simplify
 import Syntax
-import Type
+import QueryType
 import Name
 import Err
 import MTL1

src/lib/Builder.hs

@@ -67,6 +67,7 @@ import qualified RawName as R
 import Name
 import Syntax
 import Type
+import QueryType
 import PPrint (prettyBlock)
 import CheapReduction
 import {-# SOURCE #-} Inference

src/lib/Export.hs

@@ -19,6 +19,7 @@ import MTL1
 import Err
 import Syntax
 import Type
+import QueryType
 import Builder
 import Simplify
 import Imp

src/lib/Imp.hs

@@ -32,6 +32,7 @@ import Syntax
 import Type
 import Simplify
 import LabeledItems
+import QueryType
 import Util (enumerate)
 import Types.Primitives
 import Algebra qualified as A

src/lib/Inference.hs

@@ -35,6 +35,7 @@ import Name
 import Builder
 import Syntax hiding (State)
 import Type
+import QueryType
 import PPrint (pprintCanonicalized, prettyBlock)
 import CheapReduction
 import GenericTraversal

src/lib/Interpreter.hs

@@ -28,7 +28,7 @@ import Name
 import MTL1
 import Syntax
 import Simplify
-import Type
+import QueryType
 import PPrint ()
 import Util ((...))
 

src/lib/Linearize.hs

@@ -18,6 +18,7 @@ import Builder
 import Syntax
 import Type
 import MTL1
+import QueryType
 import Util (bindM2)
 import PPrint