diff --git a/examples/ptr.reid b/examples/ptr.reid
index d694349..ef9f616 100644
--- a/examples/ptr.reid
+++ b/examples/ptr.reid
@@ -1,8 +1,9 @@
 // Arithmetic, function calls and imports!
 
+import std::allocate;
 
 fn main() -> u8 {
-    let mut ptr = malloc(4);
+    let mut ptr = allocate(4);
 
     ptr[0] = 5;
 
diff --git a/reid/src/ast/process.rs b/reid/src/ast/process.rs
index 4bebf42..8ebd252 100644
--- a/reid/src/ast/process.rs
+++ b/reid/src/ast/process.rs
@@ -50,6 +50,7 @@ impl ast::Module {
                             block.into_mir(module_id),
                             (*range).as_meta(module_id),
                         ),
+                        source: module_id,
                     };
                     functions.push(def);
                 }
@@ -70,6 +71,7 @@ impl ast::Module {
                             .map(|p| (p.0, p.1 .0.into_mir(module_id)))
                             .collect(),
                         kind: mir::FunctionDefinitionKind::Extern(false),
+                        source: module_id,
                     };
                     functions.push(def);
                 }
diff --git a/reid/src/mir/fmt.rs b/reid/src/mir/fmt.rs
index 9cbba3b..53e5417 100644
--- a/reid/src/mir/fmt.rs
+++ b/reid/src/mir/fmt.rs
@@ -326,7 +326,7 @@ impl Display for Metadata {
 
 impl Display for SourceModuleId {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "Mod {}", self.0)
+        write!(f, "{}", self.0)
     }
 }
 
@@ -364,7 +364,7 @@ impl Display for TypeKind {
                 Display::fmt(len, f)?;
                 f.write_char(']')
             }
-            TypeKind::CustomType(CustomTypeKey(name, mod_id)) => write!(f, "{}:{}", mod_id, name),
+            TypeKind::CustomType(CustomTypeKey(name, mod_id)) => write!(f, "{}@{}", name, mod_id),
             TypeKind::Borrow(type_kind, false) => {
                 write!(f, "&")?;
                 Display::fmt(type_kind, f)
diff --git a/reid/src/mir/linker.rs b/reid/src/mir/linker.rs
index 14e5e13..5252432 100644
--- a/reid/src/mir/linker.rs
+++ b/reid/src/mir/linker.rs
@@ -320,6 +320,7 @@ impl<'map> Pass for LinkerPass<'map> {
                     return_type: return_type,
                     parameters: param_tys,
                     kind: super::FunctionDefinitionKind::Extern(true),
+                    source: imported_mod_id,
                 });
             }
         }
diff --git a/reid/src/mir/mod.rs b/reid/src/mir/mod.rs
index 99fea98..1372bbd 100644
--- a/reid/src/mir/mod.rs
+++ b/reid/src/mir/mod.rs
@@ -293,6 +293,7 @@ pub struct FunctionDefinition {
     pub return_type: TypeKind,
     pub parameters: Vec<(String, TypeKind)>,
     pub kind: FunctionDefinitionKind,
+    pub source: SourceModuleId,
 }
 
 #[derive(Debug)]
diff --git a/reid/src/mir/pass.rs b/reid/src/mir/pass.rs
index db63202..5409d80 100644
--- a/reid/src/mir/pass.rs
+++ b/reid/src/mir/pass.rs
@@ -295,7 +295,7 @@ impl Module {
             scope
                 .types
                 .set(
-                    CustomTypeKey(typedef.name.clone(), self.module_id),
+                    CustomTypeKey(typedef.name.clone(), typedef.source_module),
                     typedef.clone(),
                 )
                 .ok();
diff --git a/reid/src/mir/typeinference.rs b/reid/src/mir/typeinference.rs
index 35bf42f..4b729b8 100644
--- a/reid/src/mir/typeinference.rs
+++ b/reid/src/mir/typeinference.rs
@@ -322,6 +322,7 @@ impl Expression {
                 // Check that the resolved type is at least a struct, no
                 // need for further resolution.
                 let kind = expr_ty.resolve_weak().unwrap();
+                dbg!(&state.scope);
                 match kind {
                     CustomType(key) => {
                         let struct_ty = state