diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2485c59a..791937f0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@
 
 - **aiken-lang**: formatter should not erase `pub` on validators. @rvcas
 - **aiken-lang**: error on using tuple index when a tuple is returned by a generic function. @rvcas
+- **aiken-lang**: fix a regression in the Type-checker introduced in v1.0.25-alpha regarding types comparison. See #917. @KtorZ
 
 ## v1.0.26-alpha - 2024-03-25
 
diff --git a/crates/aiken-lang/src/tests/check.rs b/crates/aiken-lang/src/tests/check.rs
index a188efc4..5dcd625c 100644
--- a/crates/aiken-lang/src/tests/check.rs
+++ b/crates/aiken-lang/src/tests/check.rs
@@ -2295,3 +2295,57 @@ fn tuple_access_on_call() {
 
     assert!(check(parse(source_code)).is_ok())
 }
+
+#[test]
+fn partial_eq_call_args() {
+    let source_code = r#"
+        fn foo(a: Int, b: Int, c: Bool) -> Int {
+            todo
+        }
+
+        fn main() -> Int {
+            foo(14, 42)
+        }
+    "#;
+
+    assert!(matches!(
+        dbg!(check(parse(source_code))),
+        Err((_, Error::IncorrectFieldsArity { .. }))
+    ));
+}
+
+#[test]
+fn partial_eq_callback_args() {
+    let source_code = r#"
+        fn foo(cb: fn(Int, Int, Bool) -> Int) -> Int {
+            todo
+        }
+
+        fn main() -> Int {
+            foo(fn(a, b) { a + b })
+        }
+    "#;
+
+    assert!(matches!(
+        dbg!(check(parse(source_code))),
+        Err((_, Error::CouldNotUnify { .. }))
+    ));
+}
+
+#[test]
+fn partial_eq_callback_return() {
+    let source_code = r#"
+        fn foo(cb: fn(Int, Int) -> (Int, Int, Bool)) -> Int {
+            todo
+        }
+
+        fn main() -> Int {
+            foo(fn(a, b) { (a, b) })
+        }
+    "#;
+
+    assert!(matches!(
+        dbg!(check(parse(source_code))),
+        Err((_, Error::CouldNotUnify { .. }))
+    ));
+}
diff --git a/crates/aiken-lang/src/tipo.rs b/crates/aiken-lang/src/tipo.rs
index de766117..38a34fc9 100644
--- a/crates/aiken-lang/src/tipo.rs
+++ b/crates/aiken-lang/src/tipo.rs
@@ -96,6 +96,7 @@ impl PartialEq for Type {
                     name == name2
                         && module == module2
                         && public == public2
+                        && args.len() == args2.len()
                         && args.iter().zip(args2).all(|(left, right)| left == right)
                 } else {
                     false
@@ -109,7 +110,9 @@ impl PartialEq for Type {
                     alias: _,
                 } = other
                 {
-                    ret == ret2 && args.iter().zip(args2).all(|(left, right)| left == right)
+                    ret == ret2
+                        && args.len() == args2.len()
+                        && args.iter().zip(args2).all(|(left, right)| left == right)
                 } else {
                     false
                 }
@@ -117,6 +120,7 @@ impl PartialEq for Type {
 
             Type::Tuple { elems, alias: _ } => {
                 if let Type::Tuple { elems: elems2, .. } = other {
+                    elems.len() == elems2.len() &&
                     elems.iter().zip(elems2).all(|(left, right)| left == right)
                 } else {
                     false