diff --git a/Pantograph/Library.lean b/Pantograph/Library.lean
index 52a88b6..078ca0f 100644
--- a/Pantograph/Library.lean
+++ b/Pantograph/Library.lean
@@ -63,7 +63,7 @@ def createCoreContext (options: Array String): IO Lean.Core.Context := do
     currNamespace := Lean.Name.str .anonymous "Aniva"
     openDecls := [],     -- No 'open' directives needed
     fileName := "<Pantograph>",
-    fileMap := { source := "", positions := #[0], lines := #[1] },
+    fileMap := { source := "", positions := #[0] },
     options := options
   }
 
diff --git a/Test/Common.lean b/Test/Common.lean
index 2257c7c..7c5b6e5 100644
--- a/Test/Common.lean
+++ b/Test/Common.lean
@@ -1,5 +1,6 @@
-import Pantograph.Protocol
 import Pantograph.Goal
+import Pantograph.Library
+import Pantograph.Protocol
 import LSpec
 
 namespace Pantograph
@@ -35,12 +36,7 @@ def assertUnreachable (message: String): LSpec.TestSeq := LSpec.check message fa
 open Lean
 
 def runCoreMSeq (env: Environment) (coreM: CoreM LSpec.TestSeq): IO LSpec.TestSeq := do
-  let coreContext: Core.Context := {
-    currNamespace := Name.str .anonymous "Aniva"
-    openDecls := [],     -- No 'open' directives needed
-    fileName := "<Pantograph/Test>",
-    fileMap := { source := "", positions := #[0], lines := #[1] }
-  }
+  let coreContext: Core.Context ← createCoreContext #[]
   match ← (coreM.run' coreContext { env := env }).toBaseIO with
   | .error exception =>
     return LSpec.test "Exception" (s!"internal exception #{← exception.toMessageData.toString}" = "")
@@ -53,4 +49,9 @@ def runTermElabMInMeta { α } (termElabM: Lean.Elab.TermElabM α): Lean.MetaM α
     errToSorry := false,
   })
 
+def defaultTermElabMContext: Lean.Elab.Term.Context := {
+    declName? := some "_pantograph".toName,
+    errToSorry := false
+  }
+
 end Pantograph
diff --git a/Test/Environment.lean b/Test/Environment.lean
index 977ed7d..9e3bd70 100644
--- a/Test/Environment.lean
+++ b/Test/Environment.lean
@@ -76,7 +76,8 @@ def test_inspect (env: Environment): IO LSpec.TestSeq := do
 
 def suite: IO LSpec.TestSeq := do
   let env: Environment ← importModules
-    (imports := #["Init"].map (λ str => { module := str.toName, runtimeOnly := false }))
+    (imports := #[`Init])
+    --(imports := #["Prelude"].map (λ str => { module := str.toName, runtimeOnly := false }))
     (opts := {})
     (trustLevel := 1)
 
diff --git a/Test/Holes.lean b/Test/Holes.lean
index afad4e8..af322e9 100644
--- a/Test/Holes.lean
+++ b/Test/Holes.lean
@@ -44,16 +44,8 @@ def buildGoal (nameType: List (String × String)) (target: String) (userName?: O
 def proofRunner (env: Lean.Environment) (tests: TestM Unit): IO LSpec.TestSeq := do
   let termElabM := tests.run LSpec.TestSeq.done |>.run {} -- with default options
 
-  let coreContext: Lean.Core.Context := {
-    currNamespace := Name.append .anonymous "Aniva",
-    openDecls := [],     -- No 'open' directives needed
-    fileName := "<Pantograph>",
-    fileMap := { source := "", positions := #[0], lines := #[1] }
-  }
-  let metaM := termElabM.run' (ctx := {
-    declName? := some "_pantograph",
-    errToSorry := false
-  })
+  let coreContext: Lean.Core.Context ← createCoreContext #[]
+  let metaM := termElabM.run' (ctx := defaultTermElabMContext)
   let coreM := metaM.run'
   match ← (coreM.run' coreContext { env := env }).toBaseIO with
   | .error exception =>
@@ -169,7 +161,7 @@ def test_partial_continuation: TestM Unit := do
       return ()
     | .ok state => pure state
   addTest $ LSpec.check "(continue)" ((← state1b.serializeGoals (options := ← read)).map (·.target.pp?) =
-    #[.some "2 ≤ Nat.succ ?m", .some "Nat.succ ?m ≤ 5", .some "Nat"])
+    #[.some "2 ≤ ?m.succ", .some "?m.succ ≤ 5", .some "Nat"])
   addTest $ LSpec.test "(2 root)" state1b.rootExpr?.isNone
 
   -- Roundtrip
@@ -183,7 +175,7 @@ def test_partial_continuation: TestM Unit := do
       return ()
     | .ok state => pure state
   addTest $ LSpec.check "(continue)" ((← state1b.serializeGoals (options := ← read)).map (·.target.pp?) =
-    #[.some "2 ≤ Nat.succ ?m", .some "Nat.succ ?m ≤ 5", .some "Nat"])
+    #[.some "2 ≤ ?m.succ", .some "?m.succ ≤ 5", .some "Nat"])
   addTest $ LSpec.test "(2 root)" state1b.rootExpr?.isNone
 
   -- Continuation should fail if the state does not exist:
diff --git a/Test/Integration.lean b/Test/Integration.lean
index 0a6c210..83b3c9d 100644
--- a/Test/Integration.lean
+++ b/Test/Integration.lean
@@ -21,13 +21,7 @@ def subroutine_runner (steps: List (MainM LSpec.TestSeq)): IO LSpec.TestSeq := d
   let context: Context := {
     imports := ["Init"]
   }
-  let coreContext: Lean.Core.Context := {
-    currNamespace := Lean.Name.str .anonymous "Aniva"
-    openDecls := [],
-    fileName := "<Test>",
-    fileMap := { source := "", positions := #[0], lines := #[1] },
-    options := Lean.Options.empty
-  }
+  let coreContext: Lean.Core.Context ← createCoreContext #[]
   let commands: MainM LSpec.TestSeq :=
     steps.foldlM (λ suite step => do
       let result ← step
@@ -39,7 +33,7 @@ def subroutine_runner (steps: List (MainM LSpec.TestSeq)): IO LSpec.TestSeq := d
     return LSpec.check s!"Uncaught IO exception: {ex.toString}" false
 
 def test_option_modify : IO LSpec.TestSeq :=
-  let pp? := Option.some "∀ (n : Nat), n + 1 = Nat.succ n"
+  let pp? := Option.some "∀ (n : Nat), n + 1 = n.succ"
   let sexp? := Option.some "(:forall n (:c Nat) ((:c Eq) (:c Nat) ((:c HAdd.hAdd) (:c Nat) (:c Nat) (:c Nat) ((:c instHAdd) (:c Nat) (:c instAddNat)) 0 ((:c OfNat.ofNat) (:c Nat) (:lit 1) ((:c instOfNatNat) (:lit 1)))) ((:c Nat.succ) 0)))"
   let module? := Option.some "Init.Data.Nat.Basic"
   let options: Protocol.Options := {}
@@ -142,7 +136,7 @@ def test_env : IO LSpec.TestSeq :=
     subroutine_step "env.inspect"
       [("name", .str name2)]
      (Lean.toJson ({
-       value? := .some { pp? := .some "fun a => Int.ofNat a + 1" },
+       value? := .some { pp? := .some "fun a => ↑a + 1" },
        type := { pp? := .some "Nat → Int" },
      }:
       Protocol.EnvInspectResult))
diff --git a/Test/Proofs.lean b/Test/Proofs.lean
index 85ba66d..833c02e 100644
--- a/Test/Proofs.lean
+++ b/Test/Proofs.lean
@@ -62,16 +62,8 @@ def buildGoal (nameType: List (String × String)) (target: String) (userName?: O
 def proofRunner (env: Lean.Environment) (tests: TestM Unit): IO LSpec.TestSeq := do
   let termElabM := tests.run LSpec.TestSeq.done |>.run {} -- with default options
 
-  let coreContext: Lean.Core.Context := {
-    currNamespace := Name.append .anonymous "Aniva",
-    openDecls := [],     -- No 'open' directives needed
-    fileName := "<Pantograph>",
-    fileMap := { source := "", positions := #[0], lines := #[1] }
-  }
-  let metaM := termElabM.run' (ctx := {
-    declName? := some "_pantograph",
-    errToSorry := false
-  })
+  let coreContext: Lean.Core.Context ← createCoreContext #[]
+  let metaM := termElabM.run' (ctx := defaultTermElabMContext)
   let coreM := metaM.run'
   match ← (coreM.run' coreContext { env := env }).toBaseIO with
   | .error exception =>
@@ -235,7 +227,7 @@ def proof_or_comm: TestM Unit := do
   let state2parent ← serialize_expression_ast state2.parentExpr?.get! (sanitize := false)
   -- This is due to delayed assignment
   addTest $ LSpec.test "(2 parent)" (state2parent ==
-    "((:mv _uniq.45) (:fv _uniq.16) ((:c Eq.refl) ((:c Or) (:fv _uniq.10) (:fv _uniq.13)) (:fv _uniq.16)))")
+    "((:mv _uniq.43) (:fv _uniq.16) ((:c Eq.refl) ((:c Or) (:fv _uniq.10) (:fv _uniq.13)) (:fv _uniq.16)))")
 
   let state3_1 ← match ← state2.execute (goalId := 0) (tactic := "apply Or.inr") with
     | .success state => pure state
@@ -243,7 +235,7 @@ def proof_or_comm: TestM Unit := do
       addTest $ assertUnreachable $ other.toString
       return ()
   let state3_1parent ← serialize_expression_ast state3_1.parentExpr?.get! (sanitize := false)
-  addTest $ LSpec.test "(3_1 parent)" (state3_1parent == "((:c Or.inr) (:fv _uniq.13) (:fv _uniq.10) (:mv _uniq.83))")
+  addTest $ LSpec.test "(3_1 parent)" (state3_1parent == "((:c Or.inr) (:fv _uniq.13) (:fv _uniq.10) (:mv _uniq.78))")
   addTest $ LSpec.check "· apply Or.inr" (state3_1.goals.length = 1)
   let state4_1 ← match ← state3_1.execute (goalId := 0) (tactic := "assumption") with
     | .success state => pure state
@@ -252,7 +244,7 @@ def proof_or_comm: TestM Unit := do
       return ()
   addTest $ LSpec.check "  assumption" state4_1.goals.isEmpty
   let state4_1parent ← serialize_expression_ast state4_1.parentExpr?.get! (sanitize := false)
-  addTest $ LSpec.test "(4_1 parent)" (state4_1parent == "(:fv _uniq.49)")
+  addTest $ LSpec.test "(4_1 parent)" (state4_1parent == "(:fv _uniq.47)")
   addTest $ LSpec.check "(4_1 root)" state4_1.rootExpr?.isNone
   let state3_2 ← match ← state2.execute (goalId := 1) (tactic := "apply Or.inl") with
     | .success state => pure state
@@ -304,7 +296,7 @@ def proof_or_comm: TestM Unit := do
 
 def suite: IO LSpec.TestSeq := do
   let env: Lean.Environment ← Lean.importModules
-    (imports := #[{ module := Name.append .anonymous "Init", runtimeOnly := false}])
+    (imports := #[{ module := "Init".toName, runtimeOnly := false}])
     (opts := {})
     (trustLevel := 1)
   let tests := [
diff --git a/Test/Serial.lean b/Test/Serial.lean
index 70e86e8..490b538 100644
--- a/Test/Serial.lean
+++ b/Test/Serial.lean
@@ -20,7 +20,7 @@ def test_name_to_ast: LSpec.TestSeq :=
 def test_expr_to_binder (env: Environment): IO LSpec.TestSeq := do
   let entries: List (Name × Protocol.BoundExpression) := [
     ("Nat.add_comm".toName, { binders := #[("n", "Nat"), ("m", "Nat")], target := "n + m = m + n" }),
-    ("Nat.le_of_succ_le".toName, { binders := #[("n", "Nat"), ("m", "Nat"), ("h", "Nat.succ n ≤ m")], target := "n ≤ m" })
+    ("Nat.le_of_succ_le".toName, { binders := #[("n", "Nat"), ("m", "Nat"), ("h", "n.succ ≤ m")], target := "n ≤ m" })
   ]
   let coreM: CoreM LSpec.TestSeq := entries.foldlM (λ suites (symbol, target) => do
     let env ← MonadEnv.getEnv
@@ -58,10 +58,7 @@ def test_sexp_of_expr (env: Environment): IO LSpec.TestSeq := do
     let expr := (← syntax_to_expr s) |>.toOption |>.get!
     let test := LSpec.check source ((← serialize_expression_ast expr) = target)
     return LSpec.TestSeq.append suites test) LSpec.TestSeq.done
-  let metaM := termElabM.run' (ctx := {
-    declName? := some "_pantograph",
-    errToSorry := false
-  })
+  let metaM := termElabM.run' (ctx := defaultTermElabMContext)
   runMetaMSeq env metaM
 
 -- Instance parsing
diff --git a/flake.lock b/flake.lock
index 6278d68..1878e87 100644
--- a/flake.lock
+++ b/flake.lock
@@ -38,19 +38,20 @@
         "flake-utils": "flake-utils",
         "lean4-mode": "lean4-mode",
         "nix": "nix",
-        "nixpkgs": "nixpkgs_2"
+        "nixpkgs": "nixpkgs_2",
+        "nixpkgs-old": "nixpkgs-old"
       },
       "locked": {
-        "lastModified": 1710520221,
-        "narHash": "sha256-8Fm4bj9sqqsUHFZweSdGMM5GdUX3jkGK/ggGq27CeQc=",
+        "lastModified": 1711508550,
+        "narHash": "sha256-UK4DnYmwXLcqHA316Zkn0cnujdYlxqUf+b6S4l56Q3s=",
         "owner": "leanprover",
         "repo": "lean4",
-        "rev": "f70895ede54501adf0db77474f452a7fef40d0b3",
+        "rev": "b4caee80a3dfc5c9619d88b16c40cc3db90da4e2",
         "type": "github"
       },
       "original": {
         "owner": "leanprover",
-        "ref": "f70895ede54501adf0db77474f452a7fef40d0b3",
+        "ref": "b4caee80a3dfc5c9619d88b16c40cc3db90da4e2",
         "repo": "lean4",
         "type": "github"
       }
@@ -141,6 +142,23 @@
         "type": "github"
       }
     },
+    "nixpkgs-old": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1581379743,
+        "narHash": "sha256-i1XCn9rKuLjvCdu2UeXKzGLF6IuQePQKFt4hEKRU5oc=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "34c7eb7545d155cc5b6f499b23a7cb1c96ab4d59",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-19.03",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "nixpkgs-regression": {
       "locked": {
         "lastModified": 1643052045,
diff --git a/flake.nix b/flake.nix
index dd98225..ed89fb0 100644
--- a/flake.nix
+++ b/flake.nix
@@ -4,7 +4,7 @@
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
     flake-parts.url = "github:hercules-ci/flake-parts";
-    lean.url = "github:leanprover/lean4?ref=f70895ede54501adf0db77474f452a7fef40d0b3";
+    lean.url = "github:leanprover/lean4?ref=b4caee80a3dfc5c9619d88b16c40cc3db90da4e2";
   };
 
   outputs = inputs @ {
@@ -27,12 +27,20 @@
         roots = [ "Main" "Pantograph" ];
         src = ./.;
       };
+      test = leanPkgs.buildLeanPackage {
+        name = "Test";
+        roots = [ "Main" ];
+        src = ./Test;
+      };
     in rec {
       packages = {
         inherit (leanPkgs) lean lean-all;
         inherit (project) sharedLib executable;
         default = project.executable;
       };
+      checks = {
+        test = test.executable;
+      };
       devShells.default = project.devShell;
     };
   };
diff --git a/lean-toolchain b/lean-toolchain
index faa2254..c630636 100644
--- a/lean-toolchain
+++ b/lean-toolchain
@@ -1 +1 @@
-leanprover/lean4:4.7.0-rc2
+leanprover/lean4:nightly-2024-03-27