Add GHC 8.6.4 support

Some tests fail, need to investigate

.circleci/config.yml

@@ -141,6 +141,11 @@ jobs:
       - STACK_FILE: "stack-8.6.3.yaml"
     <<: *defaults
 
+  ghc-8.6.4:
+    environment:
+      - STACK_FILE: "stack-8.6.4.yaml"
+    <<: *defaults
+
   ghc-nightly:
     environment:
       - STACK_FILE: "stack.yaml"
@@ -192,5 +197,6 @@ workflows:
       - ghc-8.6.1
       - ghc-8.6.2
       - ghc-8.6.3
+      - ghc-8.6.4
       - ghc-nightly
       - cabal

.gitmodules

@@ -34,4 +34,8 @@
 
 [submodule "submodules/floskell"]
 	path = submodules/floskell
-	url = https://github.com/ennocramer/floskell
+	# url = https://github.com/ennocramer/floskell
+	url = https://github.com/alanz/floskell
+[submodule "submodules/monad-dijkstra"]
+	path = submodules/monad-dijkstra
+	url = https://github.com/alanz/monad-dijkstra.git

cabal.project

@@ -8,3 +8,4 @@ packages:
          ./submodules/ghc-mod/
          ./submodules/ghc-mod/core/
          ./submodules/floskell
+         ./submodules/monad-dijkstra

stack-8.6.4.yaml

@@ -0,0 +1,43 @@
+resolver: nightly-2019-03-07 # GHC 8.6.4
+packages:
+- .
+- hie-plugin-api
+
+extra-deps:
+- ./submodules/HaRe
+- ./submodules/brittany
+- ./submodules/cabal-helper
+- ./submodules/ghc-mod
+- ./submodules/ghc-mod/core
+- ./submodules/floskell
+- ./submodules/monad-dijkstra
+
+- ansi-terminal-0.8.2
+- butcher-1.3.2.1
+- cabal-plan-0.4.0.0
+- constrained-dynamic-0.1.0.0
+- deque-0.2.7
+- ghc-exactprint-0.5.8.2
+- haddock-api-2.22.0
+- hsimport-0.8.8
+# - monad-dijkstra-0.1.1.2
+- monad-memo-0.4.1
+- multistate-0.8.0.1
+# - optparse-simple-0.1.0
+- syz-0.2.0.0
+- temporary-1.2.1.1
+- transformers-0.5.6.2
+- yaml-0.8.32
+
+flags:
+  haskell-ide-engine:
+    pedantic: true
+  hie-plugin-api:
+    pedantic: true
+
+# allow-newer: true
+
+nix:
+  packages: [ icu libcxx zlib ]
+
+concurrent-tests: false

submodules/floskell

@@ -1 +1 @@
-Subproject commit 059abe627647d97c23579a14194d143d84e3e2f1
+Subproject commit f90d99167ed93ef276c3212f86ddc3402f13885b

submodules/monad-dijkstra

@@ -0,0 +1 @@
+Subproject commit 4c6168b209ab7c1b9680e869a4382a835e5a8c36