diff --git a/crates/cairo-lang-semantic/src/expr/inference/canonic.rs b/crates/cairo-lang-semantic/src/expr/inference/canonic.rs
index bdf4b627339..55a13c74b94 100644
--- a/crates/cairo-lang-semantic/src/expr/inference/canonic.rs
+++ b/crates/cairo-lang-semantic/src/expr/inference/canonic.rs
@@ -535,6 +535,9 @@ impl<'db> SemanticRewriter<TypeLongId<'db>, MapperError> for Mapper<'db, '_> {
         let TypeLongId::Var(var) = value else {
             return value.default_rewrite(self);
         };
+        if var.inference_id != self.mapping.source_inference_id {
+            return value.default_rewrite(self);
+        }
         let id = self
             .mapping
             .type_var_mapping
@@ -553,6 +556,9 @@ impl<'db> SemanticRewriter<ConstValue<'db>, MapperError> for Mapper<'db, '_> {
         let ConstValue::Var(var, ty) = value else {
             return value.default_rewrite(self);
         };
+        if var.inference_id != self.mapping.source_inference_id {
+            return value.default_rewrite(self);
+        }
         let id = self
             .mapping
             .const_var_mapping
@@ -582,6 +588,9 @@ impl<'db> SemanticRewriter<ImplLongId<'db>, MapperError> for Mapper<'db, '_> {
             return value.default_rewrite(self);
         };
         let var = var_id.long(self.get_db());
+        if var.inference_id != self.mapping.source_inference_id {
+            return value.default_rewrite(self);
+        }
         let id = self
             .mapping
             .impl_var_mapping
@@ -614,6 +623,9 @@ impl<'db> SemanticRewriter<NegativeImplLongId<'db>, MapperError> for Mapper<'db,
             return value.default_rewrite(self);
         };
         let var = var_id.long(self.get_db());
+        if var.inference_id != self.mapping.source_inference_id {
+            return value.default_rewrite(self);
+        }
         let id = self
             .mapping
             .negative_impl_var_mapping
@@ -627,3 +639,83 @@ impl<'db> SemanticRewriter<NegativeImplLongId<'db>, MapperError> for Mapper<'db,
         Ok(RewriteResult::Modified)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use cairo_lang_utils::Intern;
+    use salsa::Database;
+
+    use super::{Mapper, VarMapping};
+    use crate::expr::inference::{
+        InferenceData, InferenceId, LocalConstVarId, LocalTypeVarId, TypeVar,
+    };
+    use crate::items::constant::ConstValue;
+    use crate::test_utils::SemanticDatabaseForTesting;
+    use crate::TypeLongId;
+
+    fn overlapping_type_vars_from_inference<'db>(
+        db: &'db dyn Database,
+    ) -> (TypeVar<'db>, TypeVar<'db>) {
+        let mut source_inference_data = InferenceData::new(InferenceId::NoContext);
+        let mut source_inference = source_inference_data.inference(db);
+        let source_var = source_inference.new_type_var_raw(None);
+
+        let mut foreign_inference_data = InferenceData::new(InferenceId::Canonical);
+        let mut foreign_inference = foreign_inference_data.inference(db);
+        let foreign_var = foreign_inference.new_type_var_raw(None);
+
+        assert_eq!(source_var.id, foreign_var.id);
+        (source_var, foreign_var)
+    }
+
+    #[test]
+    fn mapper_maps_source_type_var_created_by_inference() {
+        let db = SemanticDatabaseForTesting::default();
+        let db: &dyn Database = &db;
+        let (source_var, _) = overlapping_type_vars_from_inference(db);
+        let mapped_var_id = LocalTypeVarId(source_var.id.0 + 7);
+        let original = TypeLongId::Var(source_var);
+        let mut mapping = VarMapping::new_to_canonic(source_var.inference_id);
+        mapping.type_var_mapping.insert(source_var.id, mapped_var_id);
+
+        let mapped = Mapper::map(db, original, &mapping).unwrap();
+        let TypeLongId::Var(mapped_var) = mapped else { panic!("expected type var after map") };
+        assert_eq!(mapped_var.inference_id, InferenceId::Canonical);
+        assert_eq!(mapped_var.id, mapped_var_id);
+    }
+
+    #[test]
+    fn mapper_ignores_foreign_type_var_with_overlapping_local_id() {
+        let db = SemanticDatabaseForTesting::default();
+        let db: &dyn Database = &db;
+        let (source_var, foreign_var) = overlapping_type_vars_from_inference(db);
+        let mut mapping = VarMapping::new_to_canonic(source_var.inference_id);
+        mapping.type_var_mapping.insert(source_var.id, LocalTypeVarId(source_var.id.0 + 7));
+
+        let original = TypeLongId::Var(foreign_var);
+        let mapped = Mapper::map(db, original.clone(), &mapping).unwrap();
+        assert_eq!(mapped, original);
+    }
+
+    #[test]
+    fn mapper_ignores_foreign_const_var_with_overlapping_local_id() {
+        let db = SemanticDatabaseForTesting::default();
+        let db: &dyn Database = &db;
+        let mut source_inference_data = InferenceData::new(InferenceId::NoContext);
+        let mut source_inference = source_inference_data.inference(db);
+        let source_var = source_inference.new_const_var_raw(None);
+
+        let mut foreign_inference_data = InferenceData::new(InferenceId::Canonical);
+        let mut foreign_inference = foreign_inference_data.inference(db);
+        let foreign_var = foreign_inference.new_const_var_raw(None);
+        assert_eq!(source_var.id, foreign_var.id);
+
+        let mut mapping = VarMapping::new_to_canonic(source_var.inference_id);
+        mapping.const_var_mapping.insert(source_var.id, LocalConstVarId(source_var.id.0 + 3));
+
+        let ty = TypeLongId::Tuple(vec![]).intern(db);
+        let original = ConstValue::Var(foreign_var, ty);
+        let mapped = Mapper::map(db, original.clone(), &mapping).unwrap();
+        assert_eq!(mapped, original);
+    }
+}