diff --git a/nac3type/src/inference.rs b/nac3type/src/inference.rs
index 28ef48b518..7eb63a2325 100644
--- a/nac3type/src/inference.rs
+++ b/nac3type/src/inference.rs
@@ -141,6 +141,11 @@ pub fn resolve_call(
                             resolve_call(ctx, Some(obj.clone()), func, args.clone(), assumptions)
                         })
                         .collect();
+                    // `assumption` cannot substitute variable for variable, if assumption contains
+                    // this id before running this function, `obj` would not be a variable, so this
+                    // would not be executed.
+                    // Hence, we lose no information doing this.
+                    assumptions.remove(id);
                     let results = results?;
                     if results.iter().all(|v| v == &results[0]) {
                         return Ok(results[0].clone());