diff --git a/compiler/erg_common/build.rs b/compiler/erg_common/build.rs
index 3feb4b37..17f6ada5 100644
--- a/compiler/erg_common/build.rs
+++ b/compiler/erg_common/build.rs
@@ -11,7 +11,7 @@ fn main() -> std::io::Result<()> {
     let git_hash_short = String::from_utf8_lossy(&output.stdout);
     let now = datetime::now();
     #[allow(deprecated)]
-    let erg_path = std::env::home_dir().unwrap().join(".erg");
+    let erg_path = std::env::home_dir().unwrap_or_default().join(".erg");
     println!("cargo:rustc-env=GIT_HASH_SHORT={git_hash_short}");
     println!("cargo:rustc-env=BUILD_DATE={now}");
     println!("cargo:rustc-env=CARGO_ERG_PATH={}", erg_path.display());
diff --git a/compiler/erg_common/macros.rs b/compiler/erg_common/macros.rs
index d52b4840..16a6aa62 100644
--- a/compiler/erg_common/macros.rs
+++ b/compiler/erg_common/macros.rs
@@ -269,7 +269,7 @@ macro_rules! fn_name {
         fn type_name_of<T>(_: T) -> &'static str {
             std::any::type_name::<T>()
         }
-        let name = type_name_of(dummy).rsplit("::").nth(1).unwrap();
+        let name = type_name_of(dummy).rsplit("::").nth(1).unwrap_or("?");
         &name[..]
     }};
 }
diff --git a/compiler/erg_common/python_util.rs b/compiler/erg_common/python_util.rs
index 6bb144b0..2fd67493 100644
--- a/compiler/erg_common/python_util.rs
+++ b/compiler/erg_common/python_util.rs
@@ -624,9 +624,9 @@ impl std::str::FromStr for PythonVersion {
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         let mut iter = s.split('.');
-        let major = iter.next().unwrap().parse::<u8>().unwrap_or(3);
-        let minor = iter.next().and_then(|i| i.parse::<u8>().ok());
-        let micro = iter.next().and_then(|i| i.parse::<u8>().ok());
+        let major = iter.next().and_then(|i| i.parse().ok()).unwrap_or(3);
+        let minor = iter.next().and_then(|i| i.parse().ok());
+        let micro = iter.next().and_then(|i| i.parse().ok());
         Ok(Self::new(major, minor, micro))
     }
 }
@@ -652,9 +652,9 @@ pub fn get_python_version(py_command: &str) -> PythonVersion {
     };
     let s_version = String::from_utf8(out.stdout).unwrap();
     let mut iter = s_version.split(' ');
-    let major = iter.next().unwrap().parse().unwrap();
-    let minor = iter.next().and_then(|i| i.parse::<u8>().ok());
-    let micro = iter.next().and_then(|i| i.trim_end().parse::<u8>().ok());
+    let major = iter.next().and_then(|i| i.parse().ok()).unwrap_or(3);
+    let minor = iter.next().and_then(|i| i.parse().ok());
+    let micro = iter.next().and_then(|i| i.trim_end().parse().ok());
     PythonVersion {
         major,
         minor,
diff --git a/compiler/erg_common/serialize.rs b/compiler/erg_common/serialize.rs
index 79f0d195..cc449e66 100644
--- a/compiler/erg_common/serialize.rs
+++ b/compiler/erg_common/serialize.rs
@@ -40,8 +40,8 @@ pub const fn get_ver_from_magic_num(magic_num: u32) -> PythonVersion {
 pub fn get_timestamp_bytes() -> [u8; 4] {
     let secs = SystemTime::now()
         .duration_since(UNIX_EPOCH)
-        .unwrap()
-        .as_secs() as u32;
+        .map(|dur| dur.as_secs() as u32)
+        .unwrap_or(0);
     secs.to_le_bytes()
 }
 
diff --git a/compiler/erg_common/style.rs b/compiler/erg_common/style.rs
index 6b6d623f..d0bbf710 100644
--- a/compiler/erg_common/style.rs
+++ b/compiler/erg_common/style.rs
@@ -417,7 +417,7 @@ impl StyledStrings {
     ///
     /// ```
     pub fn push_str(&mut self, s: &str) {
-        if self.is_same_color(Color::Gray) {
+        if self.color_is(Color::Gray) {
             self.texts.last_mut().unwrap().text.push_str(s);
         } else {
             self.texts.push(StyledString::new(s, None, None));
@@ -438,7 +438,7 @@ impl StyledStrings {
     /// println!("{}", texts);
     /// ```
     pub fn push_str_with_color<'a, S: Into<Cow<'a, str>>>(&mut self, s: S, color: Color) {
-        if self.is_same_color(color) {
+        if self.color_is(color) {
             let text = s.into();
             self.texts.last_mut().unwrap().text.push_str(&text);
         } else {
@@ -465,7 +465,7 @@ impl StyledStrings {
         color: Color,
         attr: Attribute,
     ) {
-        if self.is_same_color(color) && self.is_same_attribute(attr) {
+        if self.color_is(color) && self.attr_is(attr) {
             let text = s.into();
             self.texts.last_mut().unwrap().text.push_str(&text);
         } else {
@@ -482,14 +482,14 @@ impl StyledStrings {
         self.texts.iter().all(|s| s.is_empty())
     }
 
-    fn is_same_color(&self, color: Color) -> bool {
+    fn color_is(&self, color: Color) -> bool {
         if let Some(text) = self.texts.last() {
             return text.color == Some(color);
         }
         false
     }
 
-    fn is_same_attribute(&self, attr: Attribute) -> bool {
+    fn attr_is(&self, attr: Attribute) -> bool {
         if let Some(text) = self.texts.last() {
             if let Some(text_attr) = text.attribute {
                 return text_attr == attr;