Check delay is allowed before delaying

We can't nest delayed elaborators (this is an efficiency constraint, to
prevent excessive searching for ambiguous names) to run elaborator
immediately if delays aren't allowed in delayElab

CONTRIBUTING.md

@@ -18,6 +18,7 @@ beyond work on the language core, are (in no particular order):
   - Syntax highlighting support for output 
   - Several functions from the version 1 IDE protocol are not yet implemented,
     and I haven't confirmed it works in everything.
+  - (Not really part of Idris 2, but an editing mode for vim would be lovely!)
 * Some parts of the Idris 1 Prelude are not yet implemented and should be
   added to base/
 * Partial evaluation, especially for specialisation of interface 
@@ -26,7 +27,6 @@ beyond work on the language core, are (in no particular order):
   errors would be good.
   - In particular, large sections commented out with {- -} can take a while
     to lex!
-* Windows support - it is tested on macOS and Linux only so far.
 * An alternative, high performance, back end. OCaml seems worth a try.
 * JS and Node back ends would be nice.
 

Makefile

@@ -22,13 +22,13 @@ base: prelude
 
 libs : prelude base
 
-clean: lib_clean
+clean: clean-libs
 	make -C src clean
 	make -C tests clean
 	rm -f runtests
 	rm -f idris2
 
-lib_clean:
+clean-libs:
 	make -C libs/prelude clean
 	make -C libs/base clean
 
@@ -36,7 +36,9 @@ test:
 	idris --build tests.ipkg
 	make -C tests
 
-install: all install-libs
+install: all install-exec install-libs
+
+install-exec: idris2
 	install idris2 ${PREFIX}/bin
 	install support/chez/* ${PREFIX}/idris2/support/chez
 	install support/chicken/* ${PREFIX}/idris2/support/chicken

src/TTImp/Elab/Delayed.idr

@@ -60,6 +60,7 @@ delayOnFailure fc rig env expected pred elab
                     do nm <- genName "delayed"
                        (ci, dtm) <- newDelayed fc Rig1 env nm !(getTerm expected)
                        logGlueNF 5 ("Postponing elaborator " ++ show nm ++ 
+                                    " at " ++ show fc ++
                                     " for") env expected
                        log 10 ("Due to error " ++ show err)
                        ust <- get UST
@@ -86,22 +87,25 @@ delayElab : {auto c : Ref Ctxt Defs} ->
             Core (Term vars, Glued vars)
 delayElab {vars} fc rig env exp elab 
     = do est <- get EST
-         nm <- genName "delayed"
-         expected <- mkExpected exp
-         (ci, dtm) <- newDelayed fc Rig1 env nm !(getTerm expected)
-         logGlueNF 5 ("Postponing elaborator " ++ show nm ++ 
-                      " for") env expected
-         ust <- get UST
-         put UST (record { delayedElab $= 
-                 ((ci, mkClosedElab fc env 
-                           (do est <- get EST
-                               put EST (record { allowDelay = False } est)
-                               tm <- elab
-                               est <- get EST
-                               put EST (record { allowDelay = True } est)
-                               pure tm)) :: ) } 
-                         ust)
-         pure (dtm, expected)
+         if not (allowDelay est)
+            then elab
+            else do
+             nm <- genName "delayed"
+             expected <- mkExpected exp
+             (ci, dtm) <- newDelayed fc Rig1 env nm !(getTerm expected)
+             logGlueNF 5 ("Postponing elaborator " ++ show nm ++ 
+                          " for") env expected
+             ust <- get UST
+             put UST (record { delayedElab $= 
+                     ((ci, mkClosedElab fc env 
+                               (do est <- get EST
+                                   put EST (record { allowDelay = False } est)
+                                   tm <- elab
+                                   est <- get EST
+                                   put EST (record { allowDelay = True } est)
+                                   pure tm)) :: ) } 
+                             ust)
+             pure (dtm, expected)
   where
     mkExpected : Maybe (Glued vars) -> Core (Glued vars)
     mkExpected (Just ty) = pure ty
@@ -121,6 +125,7 @@ retryDelayed ((i, elab) :: ds)
     = do defs <- get Ctxt
          Just Delayed <- lookupDefExact (Resolved i) (gamma defs)
               | _ => retryDelayed ds
+         log 5 ("Retrying delayed hole " ++ show !(getFullName (Resolved i)))
          tm <- elab
          updateDef (Resolved i) (const (Just 
               (PMDef True [] (STerm tm) (STerm tm) [])))