diff --git a/crates/els/completion.rs b/crates/els/completion.rs
index 185a0ee15..47c465110 100644
--- a/crates/els/completion.rs
+++ b/crates/els/completion.rs
@@ -442,13 +442,7 @@ impl CompletionCache {
     }
 
     pub fn get(&self, namespace: &str) -> Option<MappedRwLockReadGuard<Vec<CompletionItem>>> {
-        if self.cache.borrow().get(namespace).is_some() {
-            Some(RwLockReadGuard::map(self.cache.borrow(), |cache| {
-                cache.get(namespace).unwrap()
-            }))
-        } else {
-            None
-        }
+        RwLockReadGuard::try_map(self.cache.borrow(), |cache| cache.get(namespace)).ok()
     }
 
     pub fn insert(&self, namespace: String, items: Vec<CompletionItem>) {
diff --git a/crates/els/server.rs b/crates/els/server.rs
index 1f6dc123d..0429b6df7 100644
--- a/crates/els/server.rs
+++ b/crates/els/server.rs
@@ -1151,10 +1151,7 @@ impl<Checker: BuildRunnable, Parser: Parsable> Server<Checker, Parser> {
     pub fn get_hir(&self, uri: &NormalizedUrl) -> Option<MappedRwLockReadGuard<HIR>> {
         let path = uri.to_file_path().ok()?;
         let ent = self.shared.get_module(&path)?;
-        ent.hir.as_ref()?;
-        Some(MappedRwLockReadGuard::map(ent, |ent| {
-            ent.hir.as_ref().unwrap()
-        }))
+        MappedRwLockReadGuard::try_map(ent, |ent| ent.hir.as_ref()).ok()
     }
 
     pub fn steal_entry(&self, uri: &NormalizedUrl) -> Option<ModuleEntry> {
@@ -1170,10 +1167,7 @@ impl<Checker: BuildRunnable, Parser: Parsable> Server<Checker, Parser> {
     pub fn get_ast(&self, uri: &NormalizedUrl) -> Option<MappedRwLockReadGuard<Module>> {
         let path = uri.to_file_path().ok()?;
         let ent = self.shared.get_module(&path)?;
-        ent.ast.as_ref()?;
-        Some(MappedRwLockReadGuard::map(ent, |ent| {
-            ent.ast.as_ref().unwrap()
-        }))
+        MappedRwLockReadGuard::try_map(ent, |ent| ent.ast.as_ref()).ok()
     }
 
     pub fn get_warns(&self, uri: &NormalizedUrl) -> Option<Vec<&CompileWarning>> {
diff --git a/crates/erg_compiler/module/cache.rs b/crates/erg_compiler/module/cache.rs
index 14bce069c..76fa220ff 100644
--- a/crates/erg_compiler/module/cache.rs
+++ b/crates/erg_compiler/module/cache.rs
@@ -260,13 +260,7 @@ impl SharedModuleCache {
     where
         NormalizedPathBuf: Borrow<Q>,
     {
-        if self.0.borrow().get(path).is_some() {
-            Some(RwLockReadGuard::map(self.0.borrow(), |cache| {
-                cache.get(path).unwrap()
-            }))
-        } else {
-            None
-        }
+        RwLockReadGuard::try_map(self.0.borrow(), |cache| cache.get(path)).ok()
     }
 
     pub fn get_mut<Q: Eq + Hash + ?Sized>(
@@ -276,13 +270,7 @@ impl SharedModuleCache {
     where
         NormalizedPathBuf: Borrow<Q>,
     {
-        if self.0.borrow().get(path).is_some() {
-            Some(RwLockWriteGuard::map(self.0.borrow_mut(), |cache| {
-                cache.get_mut(path).unwrap()
-            }))
-        } else {
-            None
-        }
+        RwLockWriteGuard::try_map(self.0.borrow_mut(), |cache| cache.get_mut(path)).ok()
     }
 
     pub fn ref_ctx<Q: Eq + Hash + ?Sized>(
@@ -292,13 +280,10 @@ impl SharedModuleCache {
     where
         NormalizedPathBuf: Borrow<Q>,
     {
-        if self.0.borrow().get(path).is_some() {
-            Some(RwLockReadGuard::map(self.0.borrow(), |cache| {
-                &cache.get(path).unwrap().module
-            }))
-        } else {
-            None
-        }
+        RwLockReadGuard::try_map(self.0.borrow(), |cache| {
+            cache.get(path).map(|ent| &ent.module)
+        })
+        .ok()
     }
 
     /// FIXME: see the comment in this function
diff --git a/crates/erg_compiler/module/graph.rs b/crates/erg_compiler/module/graph.rs
index 214314f5a..65412e739 100644
--- a/crates/erg_compiler/module/graph.rs
+++ b/crates/erg_compiler/module/graph.rs
@@ -225,13 +225,7 @@ impl SharedModuleGraph {
         &self,
         path: &NormalizedPathBuf,
     ) -> Option<MappedRwLockReadGuard<Node<NormalizedPathBuf, ()>>> {
-        if self.0.borrow().get_node(path).is_some() {
-            Some(RwLockReadGuard::map(self.0.borrow(), |graph| {
-                graph.get_node(path).unwrap()
-            }))
-        } else {
-            None
-        }
+        RwLockReadGuard::try_map(self.0.borrow(), |graph| graph.get_node(path)).ok()
     }
 
     pub fn depends_on(&self, path: &NormalizedPathBuf, target: &NormalizedPathBuf) -> bool {
diff --git a/crates/erg_compiler/module/impls.rs b/crates/erg_compiler/module/impls.rs
index 37c32a616..09b940b43 100644
--- a/crates/erg_compiler/module/impls.rs
+++ b/crates/erg_compiler/module/impls.rs
@@ -119,13 +119,7 @@ impl SharedTraitImpls {
     where
         Str: Borrow<Q>,
     {
-        if self.0.borrow().get(path).is_some() {
-            Some(RwLockReadGuard::map(self.0.borrow(), |tis| {
-                tis.get(path).unwrap()
-            }))
-        } else {
-            None
-        }
+        RwLockReadGuard::try_map(self.0.borrow(), |tis| tis.get(path)).ok()
     }
 
     pub fn get_mut<Q: Eq + Hash + ?Sized>(
@@ -135,13 +129,7 @@ impl SharedTraitImpls {
     where
         Str: Borrow<Q>,
     {
-        if self.0.borrow().get(path).is_some() {
-            Some(RwLockWriteGuard::map(self.0.borrow_mut(), |tis| {
-                tis.get_mut(path).unwrap()
-            }))
-        } else {
-            None
-        }
+        RwLockWriteGuard::try_map(self.0.borrow_mut(), |tis| tis.get_mut(path)).ok()
     }
 
     pub fn register(&self, name: Str, impls: Set<TraitImpl>) {
diff --git a/crates/erg_compiler/module/index.rs b/crates/erg_compiler/module/index.rs
index 4e52ff5e5..115155e94 100644
--- a/crates/erg_compiler/module/index.rs
+++ b/crates/erg_compiler/module/index.rs
@@ -171,13 +171,7 @@ impl SharedModuleIndex {
         &self,
         referee: &AbsLocation,
     ) -> Option<MappedRwLockReadGuard<ModuleIndexValue>> {
-        if self.0.borrow().get_refs(referee).is_some() {
-            Some(RwLockReadGuard::map(self.0.borrow(), |index| {
-                index.get_refs(referee).unwrap()
-            }))
-        } else {
-            None
-        }
+        RwLockReadGuard::try_map(self.0.borrow(), |index| index.get_refs(referee)).ok()
     }
 
     pub fn members(&self) -> Members {
diff --git a/crates/erg_compiler/ty/free.rs b/crates/erg_compiler/ty/free.rs
index f93b3ff34..ecf7b110f 100644
--- a/crates/erg_compiler/ty/free.rs
+++ b/crates/erg_compiler/ty/free.rs
@@ -1124,41 +1124,29 @@ impl<T: Clone + Send + Sync + 'static> Free<T> {
 
     #[track_caller]
     pub fn get_linked_ref(&self) -> Option<Ref<T>> {
-        if !self.is_linked() {
-            None
-        } else {
-            let mapped = Ref::map(self.borrow(), |f| match f {
-                FreeKind::Linked(t) | FreeKind::UndoableLinked { t, .. } => t,
-                FreeKind::Unbound { .. } | FreeKind::NamedUnbound { .. } => unreachable!(),
-            });
-            Some(mapped)
-        }
+        Ref::filter_map(self.borrow(), |f| match f {
+            FreeKind::Linked(t) | FreeKind::UndoableLinked { t, .. } => Some(t),
+            FreeKind::Unbound { .. } | FreeKind::NamedUnbound { .. } => None,
+        })
+        .ok()
     }
 
     #[track_caller]
     pub fn get_linked_refmut(&self) -> Option<RefMut<T>> {
-        if !self.is_linked() {
-            None
-        } else {
-            let mapped = RefMut::map(self.borrow_mut(), |f| match f {
-                FreeKind::Linked(t) | FreeKind::UndoableLinked { t, .. } => t,
-                FreeKind::Unbound { .. } | FreeKind::NamedUnbound { .. } => unreachable!(),
-            });
-            Some(mapped)
-        }
+        RefMut::filter_map(self.borrow_mut(), |f| match f {
+            FreeKind::Linked(t) | FreeKind::UndoableLinked { t, .. } => Some(t),
+            FreeKind::Unbound { .. } | FreeKind::NamedUnbound { .. } => None,
+        })
+        .ok()
     }
 
     #[track_caller]
     pub fn get_previous(&self) -> Option<Ref<Box<FreeKind<T>>>> {
-        if !self.is_undoable_linked() {
-            None
-        } else {
-            let mapped = Ref::map(self.borrow(), |f| match f {
-                FreeKind::UndoableLinked { previous, .. } => previous,
-                _ => unreachable!(),
-            });
-            Some(mapped)
-        }
+        Ref::filter_map(self.borrow(), |f| match f {
+            FreeKind::UndoableLinked { previous, .. } => Some(previous),
+            _ => None,
+        })
+        .ok()
     }
 
     pub fn detach(&self) -> Self {
diff --git a/crates/erg_compiler/ty/mod.rs b/crates/erg_compiler/ty/mod.rs
index a474ab7aa..eb85caa0b 100644
--- a/crates/erg_compiler/ty/mod.rs
+++ b/crates/erg_compiler/ty/mod.rs
@@ -3990,10 +3990,8 @@ impl Type {
 
     pub fn tyvar_mut_return_t(&mut self) -> Option<RefMut<Type>> {
         match self {
-            Self::FreeVar(fv) if fv.get_linked()?.return_t().is_some() => {
-                Some(RefMut::map(fv.borrow_mut(), |fk| {
-                    fk.linked_mut().unwrap().mut_return_t().unwrap()
-                }))
+            Self::FreeVar(fv) => {
+                RefMut::filter_map(fv.borrow_mut(), |fv| fv.linked_mut()?.mut_return_t()).ok()
             }
             _ => None,
         }