diff --git a/reid/src/lib.rs b/reid/src/lib.rs
index e80bcc4..15ff340 100644
--- a/reid/src/lib.rs
+++ b/reid/src/lib.rs
@@ -158,7 +158,7 @@ pub fn compile(source: &str, path: PathBuf) -> Result<String, ReidError> {
 
     println!("{}", &mir_context);
 
-    perform_all_passes(&mut mir_context);
+    perform_all_passes(&mut mir_context)?;
 
     let mut context = Context::new();
     let codegen_modules = mir_context.codegen(&mut context);
diff --git a/reid/src/mir/typeinference.rs b/reid/src/mir/typeinference.rs
index 03f7968..2ca430b 100644
--- a/reid/src/mir/typeinference.rs
+++ b/reid/src/mir/typeinference.rs
@@ -9,7 +9,7 @@ use std::iter;
 use crate::{mir::TypeKind, util::try_all};
 
 use super::{
-    pass::{Pass, PassState, ScopeVariable},
+    pass::{Pass, PassState},
     typecheck::ErrorKind,
     typerefs::{ScopeTypeRefs, TypeRef, TypeRefs},
     types::{pick_return, ReturnType},
@@ -43,7 +43,7 @@ impl FunctionDefinition {
         type_refs: &TypeRefs,
         state: &mut PassState<ErrorKind>,
     ) -> Result<(), ErrorKind> {
-        let mut scope_hints = ScopeTypeRefs::from(type_refs);
+        let scope_hints = ScopeTypeRefs::from(type_refs);
         for param in &self.parameters {
             let param_t = state.or_else(param.1.assert_known(), Vague(Unknown), self.signature());
             let res = scope_hints