diff --git a/.woodpecker/build_egui.yaml b/.woodpecker/build_egui.yaml
index 79478ee..3c28a2b 100644
--- a/.woodpecker/build_egui.yaml
+++ b/.woodpecker/build_egui.yaml
@@ -1,10 +1,14 @@
 matrix:
-  RUST: [stable, nightly]
+  include:
+    - CHANNEL: stable
+      FEATURES: egui,disable_contracts
+    - CHANNEL: nightly
+      FEATURES: egui
 
 steps:
   build_egui:
     image: rust
     environment: [CARGO_TERM_COLOR=always]
     commands:
-      - rustup default $RUST
-      - cargo build --features "egui" --bin "topola-egui"
+      - rustup default "$CHANNEL"
+      - cargo build --features "$FEATURES" --bin "topola-egui"
diff --git a/.woodpecker/build_sdl2.yaml b/.woodpecker/build_sdl2.yaml
index dfbdd5a..f3f782a 100644
--- a/.woodpecker/build_sdl2.yaml
+++ b/.woodpecker/build_sdl2.yaml
@@ -1,5 +1,9 @@
 matrix:
-  RUST: [stable, nightly]
+  include:
+    - CHANNEL: stable
+      FEATURES: sdl2,disable_contracts
+    - CHANNEL: nightly
+      FEATURES: sdl2
 
 steps:
   build_sdl2:
@@ -8,5 +12,5 @@ steps:
     commands:
       - apt-get update
       - apt-get -y install cmake
-      - rustup default $RUST
-      - cargo build --features "sdl2" --bin "topola-sdl2-demo"
+      - rustup default "$CHANNEL"
+      - cargo build --features "$FEATURES" --bin "topola-sdl2-demo"
diff --git a/.woodpecker/test.yaml b/.woodpecker/test.yaml
index 9c4053f..ecfceb7 100644
--- a/.woodpecker/test.yaml
+++ b/.woodpecker/test.yaml
@@ -1,11 +1,15 @@
 matrix:
-  RUST: [stable, nightly]
+  include:
+    - CHANNEL: stable
+      FEATURES: disable_contracts
+    - CHANNEL: nightly
+      FEATURES:
 
 steps:
   test:
     image: rust
     environment: [CARGO_TERM_COLOR=always]
     commands:
-      - rustup default $RUST
+      - rustup default "$CHANNEL"
       - cargo check
-      - cargo test
+      - cargo test --features "$FEATURES"
diff --git a/Cargo.toml b/Cargo.toml
index a9793bc..83cc0dd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,6 +18,7 @@ required-features = ["sdl2"]
 [features]
 egui = ["dep:eframe", "dep:egui", "dep:rfd", "dep:futures"]
 sdl2 = ["dep:sdl2", "dep:gl", "dep:pathfinder_canvas", "dep:pathfinder_geometry", "dep:pathfinder_gl", "dep:pathfinder_renderer", "dep:pathfinder_resources"]
+disable_contracts = ["contracts/disable_contracts"]
 
 [dependencies]
 thiserror = "1.0.56"
diff --git a/src/lib.rs b/src/lib.rs
index 78a76fe..fc75618a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,4 +1,4 @@
-#![feature(try_blocks)]
+#![cfg_attr(not(feature = "disable_contracts"), feature(try_blocks))]
 
 pub mod graph;
 #[macro_use]
diff --git a/vendored/contracts/Cargo.toml b/vendored/contracts/Cargo.toml
index 18970c0..e23db15 100644
--- a/vendored/contracts/Cargo.toml
+++ b/vendored/contracts/Cargo.toml
@@ -38,4 +38,3 @@ mirai_assertions = []
 syn = { version = "1.0", features = ["extra-traits", "full", "visit", "visit-mut"] }
 quote = "1.0"
 proc-macro2 = "1.0"
-rustc_version = "0.4"
diff --git a/vendored/contracts/src/lib.rs b/vendored/contracts/src/lib.rs
index 42d3ebf..a4c0348 100644
--- a/vendored/contracts/src/lib.rs
+++ b/vendored/contracts/src/lib.rs
@@ -180,8 +180,6 @@ extern crate proc_macro;
 
 mod implementation;
 
-use rustc_version::{version, version_meta, Channel, Version};
-
 use implementation::ContractMode;
 use proc_macro::TokenStream;
 
@@ -199,7 +197,7 @@ use proc_macro::TokenStream;
 /// ```
 #[proc_macro_attribute]
 pub fn requires(attr: TokenStream, toks: TokenStream) -> TokenStream {
-    if let Channel::Nightly = version_meta().unwrap().channel {
+    if cfg!(feature = "disable_contracts") {
         return toks;
     }
 
@@ -213,7 +211,7 @@ pub fn requires(attr: TokenStream, toks: TokenStream) -> TokenStream {
 /// [`requires`]: attr.requires.html
 #[proc_macro_attribute]
 pub fn debug_requires(attr: TokenStream, toks: TokenStream) -> TokenStream {
-    if let Channel::Nightly = version_meta().unwrap().channel {
+    if cfg!(feature = "disable_contracts") {
         return toks;
     }
 
@@ -227,7 +225,7 @@ pub fn debug_requires(attr: TokenStream, toks: TokenStream) -> TokenStream {
 /// [`requires`]: attr.requires.html
 #[proc_macro_attribute]
 pub fn test_requires(attr: TokenStream, toks: TokenStream) -> TokenStream {
-    if let Channel::Nightly = version_meta().unwrap().channel {
+    if cfg!(feature = "disable_contracts") {
         return toks;
     }
 
@@ -266,7 +264,7 @@ pub fn test_requires(attr: TokenStream, toks: TokenStream) -> TokenStream {
 /// ```
 #[proc_macro_attribute]
 pub fn ensures(attr: TokenStream, toks: TokenStream) -> TokenStream {
-    if let Channel::Nightly = version_meta().unwrap().channel {
+    if cfg!(feature = "disable_contracts") {
         return toks;
     }
 
@@ -280,7 +278,7 @@ pub fn ensures(attr: TokenStream, toks: TokenStream) -> TokenStream {
 /// [`ensures`]: attr.ensures.html
 #[proc_macro_attribute]
 pub fn debug_ensures(attr: TokenStream, toks: TokenStream) -> TokenStream {
-    if let Channel::Nightly = version_meta().unwrap().channel {
+    if cfg!(feature = "disable_contracts") {
         return toks;
     }
 
@@ -294,7 +292,7 @@ pub fn debug_ensures(attr: TokenStream, toks: TokenStream) -> TokenStream {
 /// [`ensures`]: attr.ensures.html
 #[proc_macro_attribute]
 pub fn test_ensures(attr: TokenStream, toks: TokenStream) -> TokenStream {
-    if let Channel::Nightly = version_meta().unwrap().channel {
+    if cfg!(feature = "disable_contracts") {
         return toks;
     }
 
@@ -346,7 +344,7 @@ pub fn test_ensures(attr: TokenStream, toks: TokenStream) -> TokenStream {
 /// ```
 #[proc_macro_attribute]
 pub fn invariant(attr: TokenStream, toks: TokenStream) -> TokenStream {
-    if let Channel::Nightly = version_meta().unwrap().channel {
+    if cfg!(feature = "disable_contracts") {
         return toks;
     }
 
@@ -367,7 +365,7 @@ pub fn invariant(attr: TokenStream, toks: TokenStream) -> TokenStream {
 /// [`invariant`]: attr.invariant.html
 #[proc_macro_attribute]
 pub fn debug_invariant(attr: TokenStream, toks: TokenStream) -> TokenStream {
-    if let Channel::Nightly = version_meta().unwrap().channel {
+    if cfg!(feature = "disable_contracts") {
         return toks;
     }
 
@@ -382,7 +380,7 @@ pub fn debug_invariant(attr: TokenStream, toks: TokenStream) -> TokenStream {
 /// [`invariant`]: attr.invariant.html
 #[proc_macro_attribute]
 pub fn test_invariant(attr: TokenStream, toks: TokenStream) -> TokenStream {
-    if let Channel::Nightly = version_meta().unwrap().channel {
+    if cfg!(feature = "disable_contracts") {
         return toks;
     }
 
@@ -427,7 +425,7 @@ pub fn test_invariant(attr: TokenStream, toks: TokenStream) -> TokenStream {
 /// ```
 #[proc_macro_attribute]
 pub fn contract_trait(attrs: TokenStream, toks: TokenStream) -> TokenStream {
-    if let Channel::Nightly = version_meta().unwrap().channel {
+    if cfg!(feature = "disable_contracts") {
         return toks;
     }