update to megaparsec-9.6.1 (#1609)

* Update to `megaparsec-9.6.1`.  This allows us to remove any annoying workaround. 
* Bump stack resolver to LTS-21.19.
* Drop support for GHC 8.10.

.github/workflows/haskell-ci.yml

@@ -77,11 +77,6 @@ jobs:
             compilerVersion: 9.0.2
             setup-method: ghcup
             allow-failure: false
-          - compiler: ghc-8.10.7
-            compilerKind: ghc
-            compilerVersion: 8.10.7
-            setup-method: ghcup
-            allow-failure: false
       fail-fast: false
     steps:
       - name: apt

.mergify.yml

@@ -18,7 +18,6 @@ queue_rules:
           - check-success=Haskell-CI - Linux - ghc-9.4.5
           - check-success=Haskell-CI - Linux - ghc-9.2.7
           - check-success=Haskell-CI - Linux - ghc-9.0.2
-          - check-success=Haskell-CI - Linux - ghc-8.10.7
 
 pull_request_rules:
 - actions:
@@ -49,7 +48,6 @@ pull_request_rules:
       - check-success=Haskell-CI - Linux - ghc-9.4.5
       - check-success=Haskell-CI - Linux - ghc-9.2.7
       - check-success=Haskell-CI - Linux - ghc-9.0.2
-      - check-success=Haskell-CI - Linux - ghc-8.10.7
   - label=merge me
   - ! '#approved-reviews-by>=1'
   - ! '#changes-requested-reviews-by=0'

src/Swarm/Language/Parse.hs

@@ -60,6 +60,7 @@ import Text.Megaparsec hiding (runParser)
 import Text.Megaparsec.Char
 import Text.Megaparsec.Char.Lexer qualified as L
 import Text.Megaparsec.Pos qualified as Pos
+import Text.Megaparsec.State (initialPosState, initialState)
 import Witch
 
 -- Imports for doctests (cabal-docspec needs this)
@@ -486,24 +487,13 @@ runParserTH (file, line, col) p s =
     Left err -> fail $ errorBundlePretty err
     Right e -> return e
  where
-  -- This is annoying --- megaparsec does not export its function to
-  -- construct an initial parser state, so we can't just use that
-  -- and then change the one field we need to be different (the
-  -- 'pstateSourcePos'). We have to copy-paste the whole thing.
   initState :: State Text Void
   initState =
-    State
-      { stateInput = from s
-      , stateOffset = 0
-      , statePosState =
-          PosState
-            { pstateInput = from s
-            , pstateOffset = 0
-            , pstateSourcePos = SourcePos file (mkPos line) (mkPos col)
-            , pstateTabWidth = defaultTabWidth
-            , pstateLinePrefix = ""
+    (initialState file (from s))
+      { statePosState =
+          (initialPosState file (from s))
+            { pstateSourcePos = SourcePos file (mkPos line) (mkPos col)
             }
-      , stateParseErrors = []
       }
 
 -- | Parse some input 'Text' completely as a 'Term', consuming leading

stack.yaml

@@ -10,6 +10,7 @@ extra-deps:
 # breaking changes; see https://github.com/swarm-game/swarm/issues/1350
 - lsp-1.6.0.0
 - lsp-types-1.6.0.0
+- megaparsec-9.6.1
 - AhoCorasick-0.0.4
-resolver: lts-21.0
+resolver: lts-21.19
 

swarm.cabal

@@ -32,7 +32,7 @@ maintainer:         byorgey@gmail.com
 bug-reports:        https://github.com/swarm-game/swarm/issues
 copyright:          Brent Yorgey 2021
 category:           Game
-tested-with:        GHC ==8.10.7 || ==9.0.2 || ==9.2.7 || ==9.4.5 || ==9.6.2
+tested-with:        GHC ==9.0.2 || ==9.2.7 || ==9.4.5 || ==9.6.2
 extra-source-files: CHANGELOG.md
                     example/*.sw
                     editors/emacs/*.el
@@ -277,7 +277,7 @@ library
                       lens                          >= 4.19 && < 5.3,
                       linear                        >= 1.21.6 && < 1.23,
                       lsp                           >= 1.6 && < 1.7,
-                      megaparsec                    >= 9.0 && < 9.6,
+                      megaparsec                    >= 9.6.1 && < 9.7,
                       minimorph                     >= 0.3 && < 0.4,
                       transformers                  >= 0.5 && < 0.7,
                       mtl                           >= 2.2.2 && < 2.4,