diff --git a/.github/workflows/linting.yml b/.github/workflows/linting.yml
index 685b93a..470a576 100644
--- a/.github/workflows/linting.yml
+++ b/.github/workflows/linting.yml
@@ -7,6 +7,14 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+      - uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+      - run: rm rust-toolchain.toml
       - uses: EmbarkStudios/cargo-deny-action@v1
         with:
           arguments: --all-features
@@ -16,9 +24,17 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+      - uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+      - run: rm rust-toolchain.toml
       - uses: dtolnay/rust-toolchain@stable
         with:
-          toolchain: nightly
+          toolchain: nightly-2023-06-19
           components: clippy, rust-src
       - run: cargo clippy --all-features -- --deny warnings
   code-format:
@@ -26,8 +42,16 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+      - uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+      - run: rm rust-toolchain.toml
       - uses: dtolnay/rust-toolchain@stable
         with:
-          toolchain: nightly
+          toolchain: nightly-2023-06-19
           components: rustfmt, rust-src
       - run: cargo fmt -- --check
diff --git a/.github/workflows/testing.yml b/.github/workflows/testing.yml
index e4994ea..09de330 100644
--- a/.github/workflows/testing.yml
+++ b/.github/workflows/testing.yml
@@ -12,12 +12,23 @@ jobs:
           - macos
         rust:
           - stable
-          - nightly
+          - nightly-2023-06-19
     name: Test Rust ${{ matrix.rust }} on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}-latest
     steps:
       - uses: actions/checkout@v2
+      - uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+      - run: rm rust-toolchain.toml
       - uses: dtolnay/rust-toolchain@stable
         with:
           toolchain: ${{ matrix.rust }}
+      - uses: KyleMayes/install-llvm-action@v1
+        with:
+          version: "15.0"
       - run: cargo test --all-features --no-fail-fast
diff --git a/Cargo.toml b/Cargo.toml
index cd103f5..62c6d45 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,4 +1,5 @@
 [workspace]
+resolver = "2"
 members = [ "sloth" ]
 
 [workspace.package]
diff --git a/flake.nix b/flake.nix
index 5c82957..5143ddf 100644
--- a/flake.nix
+++ b/flake.nix
@@ -27,9 +27,17 @@
           rustc = rustStable;
         };
       in
+      let
+        baseNativeBuildInputs = with pkgs; [ pkg-config ];
+        baseBuildInputs = with pkgs; [ 
+          llvmPackages_15.libllvm
+          libffi
+          libxml2
+        ];
+      in
       with pkgs;
       {
-        packages.default = rustPlatform.buildRustPackage rec {
+        packages.default = rustPlatform.buildRustPackage {
           pname = "sloth";
           version = "0.1.0";
           src = ./.;
@@ -40,14 +48,20 @@
             lockFile = ./Cargo.lock;
           };
 
+          nativeBuildInputs = baseNativeBuildInputs;
+          buildInputs = baseBuildInputs;
+
           meta = with lib; {
             description = "The Sloth programming language";
             homepage = "https://slothlang.tech";
             license = with licenses; [ mit asl20 ];
           };
+
+          LLVM_SYS_150_PREFIX = "${llvmPackages_15.libllvm.dev}";
         };
         devShells.default = mkShell {
-          buildInputs = [
+          nativeBuildInputs = baseNativeBuildInputs;
+          buildInputs = baseBuildInputs ++ [
             (rustNightly.override {
               extensions = [ "rust-src" "rust-analyzer" ];
               targets = [ "wasm32-unknown-unknown" ];
@@ -57,16 +71,11 @@
             cargo-deny
             cargo-release
 
-            pkg-config
-
-            # Packages required for LLVM
-            llvmPackages_15.libllvm
-            libffi
-            libxml2
-
             # C compiler for debugging
             clang
           ];
+
+          RUST_BACKTRACE = 1;
         };
       }
     );
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
index 4e70b08..0a8868e 100644
--- a/rust-toolchain.toml
+++ b/rust-toolchain.toml
@@ -1,2 +1,5 @@
 [toolchain]
-channel = "nightly-2023-06-15"
+channel = "nightly-2023-06-19"
+components = [ "rust-src", "rust-analyzer" ]
+targets = [ "wasm32-unknown-unknown" ]
+profile = "default"
diff --git a/sloth/src/analysis/mod.rs b/sloth/src/analysis/mod.rs
index 1c2f0d2..a569c50 100644
--- a/sloth/src/analysis/mod.rs
+++ b/sloth/src/analysis/mod.rs
@@ -34,12 +34,26 @@ pub fn analyze(root: &mut Stmt) -> Result<(), AnalysisError> {
 }
 
 fn check_usage(node: &AstNode) -> Result<(), AnalysisError> {
-    if let AstNode::Expr(expr) = node && let ExprKind::Identifier(identifier) = &expr.kind && !expr.symtable.clone().contains(identifier) {
-        return Err(AnalysisError::UnknownIdentifier(expr.line, identifier.clone()));
+    if let AstNode::Expr(expr) = node {
+        if let ExprKind::Identifier(identifier) = &expr.kind {
+            if !expr.symtable.clone().contains(identifier) {
+                return Err(AnalysisError::UnknownIdentifier(
+                    expr.line,
+                    identifier.clone(),
+                ));
+            }
+        }
     }
 
-    if let AstNode::Stmt(stmt) = node && let StmtKind::AssignVariable { identifier, .. } = &stmt.kind && !stmt.symtable.clone().contains(identifier) {
-        return Err(AnalysisError::UnknownIdentifier(stmt.line, identifier.clone()));
+    if let AstNode::Stmt(stmt) = node {
+        if let StmtKind::AssignVariable { identifier, .. } = &stmt.kind {
+            if !stmt.symtable.clone().contains(identifier) {
+                return Err(AnalysisError::UnknownIdentifier(
+                    stmt.line,
+                    identifier.clone(),
+                ));
+            }
+        }
     }
 
     for child in node.children() {
diff --git a/sloth/src/main.rs b/sloth/src/main.rs
index b34dd4f..c181a3b 100644
--- a/sloth/src/main.rs
+++ b/sloth/src/main.rs
@@ -1,4 +1,3 @@
-#![feature(let_chains)]
 #![warn(
     clippy::wildcard_imports,
     clippy::string_add,