diff --git a/compiler/erg_compiler/artifact.rs b/compiler/erg_compiler/artifact.rs
new file mode 100644
index 00000000..fda4ac16
--- /dev/null
+++ b/compiler/erg_compiler/artifact.rs
@@ -0,0 +1,25 @@
+use crate::error::CompileErrors;
+use crate::hir::HIR;
+
+pub struct CompleteArtifact {
+    pub hir: HIR,
+    pub warns: CompileErrors,
+}
+
+impl CompleteArtifact {
+    pub const fn new(hir: HIR, warns: CompileErrors) -> Self {
+        Self { hir, warns }
+    }
+}
+
+pub struct IncompleteArtifact {
+    pub hir: Option<HIR>,
+    pub errors: CompileErrors,
+    pub warns: CompileErrors,
+}
+
+impl IncompleteArtifact {
+    pub const fn new(hir: Option<HIR>, errors: CompileErrors, warns: CompileErrors) -> Self {
+        Self { hir, errors, warns }
+    }
+}
diff --git a/compiler/erg_compiler/build_hir.rs b/compiler/erg_compiler/build_hir.rs
index 02315a7d..c73f3116 100644
--- a/compiler/erg_compiler/build_hir.rs
+++ b/compiler/erg_compiler/build_hir.rs
@@ -6,6 +6,7 @@ use erg_common::Str;
 use erg_parser::ast::AST;
 use erg_parser::build_ast::ASTBuilder;
 
+use crate::artifact::{CompleteArtifact, IncompleteArtifact};
 use crate::context::Context;
 use crate::effectcheck::SideEffectChecker;
 use crate::error::{CompileError, CompileErrors};
@@ -48,7 +49,7 @@ impl Runnable for HIRBuilder {
     fn exec(&mut self) -> Result<i32, Self::Errs> {
         let mut builder = ASTBuilder::new(self.cfg().copy());
         let ast = builder.build(self.input().read())?;
-        let hir = self.check(ast, "exec").map_err(|(_, errs)| errs)?;
+        let hir = self.check(ast, "exec").map_err(|arti| arti.errors)?;
         println!("{hir}");
         Ok(0)
     }
@@ -56,7 +57,7 @@ impl Runnable for HIRBuilder {
     fn eval(&mut self, src: String) -> Result<String, Self::Errs> {
         let mut builder = ASTBuilder::new(self.cfg().copy());
         let ast = builder.build(src)?;
-        let hir = self.check(ast, "eval").map_err(|(_, errs)| errs)?;
+        let hir = self.check(ast, "eval").map_err(|arti| arti.errors)?;
         Ok(hir.to_string())
     }
 }
@@ -74,29 +75,32 @@ impl HIRBuilder {
         }
     }
 
-    pub fn check(&mut self, ast: AST, mode: &str) -> Result<HIR, (Option<HIR>, CompileErrors)> {
-        let (hir, warns) = self.lowerer.lower(ast, mode)?;
+    pub fn check(&mut self, ast: AST, mode: &str) -> Result<HIR, IncompleteArtifact> {
+        let artifact = self.lowerer.lower(ast, mode)?;
         if self.cfg().verbose >= 2 {
-            warns.fmt_all_stderr();
+            artifact.warns.fmt_all_stderr();
         }
         let effect_checker = SideEffectChecker::new(self.cfg().clone());
-        let hir = effect_checker
-            .check(hir)
-            .map_err(|(hir, errs)| (Some(hir), errs))?;
-        let hir = self
-            .ownership_checker
-            .check(hir)
-            .map_err(|(hir, errs)| (Some(hir), errs))?;
+        let hir = effect_checker.check(artifact.hir).map_err(|(hir, errs)| {
+            IncompleteArtifact::new(Some(hir), errs, CompileErrors::empty())
+        })?;
+        let hir = self.ownership_checker.check(hir).map_err(|(hir, errs)| {
+            IncompleteArtifact::new(Some(hir), errs, CompileErrors::empty())
+        })?;
         Ok(hir)
     }
 
-    pub fn build(&mut self, src: String, mode: &str) -> Result<HIR, (Option<HIR>, CompileErrors)> {
+    pub fn build(
+        &mut self,
+        src: String,
+        mode: &str,
+    ) -> Result<CompleteArtifact, IncompleteArtifact> {
         let mut ast_builder = ASTBuilder::new(self.cfg().copy());
-        let ast = ast_builder
-            .build(src)
-            .map_err(|errs| (None, CompileErrors::from(errs)))?;
+        let ast = ast_builder.build(src).map_err(|errs| {
+            IncompleteArtifact::new(None, CompileErrors::from(errs), CompileErrors::empty())
+        })?;
         let hir = self.check(ast, mode)?;
-        Ok(hir)
+        Ok(CompleteArtifact::new(hir, CompileErrors::empty()))
     }
 
     pub fn pop_mod_ctx(&mut self) -> Context {
diff --git a/compiler/erg_compiler/compile.rs b/compiler/erg_compiler/compile.rs
index 778868f1..a6536395 100644
--- a/compiler/erg_compiler/compile.rs
+++ b/compiler/erg_compiler/compile.rs
@@ -193,9 +193,12 @@ impl Compiler {
     }
 
     fn build_link_desugar(&mut self, src: String, mode: &str) -> Result<HIR, CompileErrors> {
-        let hir = self.builder.build(src, mode).map_err(|(_, errs)| errs)?;
+        let artifact = self
+            .builder
+            .build(src, mode)
+            .map_err(|artifact| artifact.errors)?;
         let linker = Linker::new(&self.cfg, &self.mod_cache);
-        let hir = linker.link(hir);
+        let hir = linker.link(artifact.hir);
         Ok(HIRDesugarer::desugar(hir))
     }
 }
diff --git a/compiler/erg_compiler/context/register.rs b/compiler/erg_compiler/context/register.rs
index 61041c89..58e97393 100644
--- a/compiler/erg_compiler/context/register.rs
+++ b/compiler/erg_compiler/context/register.rs
@@ -1071,14 +1071,14 @@ impl Context {
         let mut builder =
             HIRBuilder::new_with_cache(cfg, __name__, mod_cache.clone(), py_mod_cache.clone());
         match builder.build(src, "exec") {
-            Ok(hir) => {
-                mod_cache.register(path.clone(), Some(hir), builder.pop_mod_ctx());
+            Ok(artifact) => {
+                mod_cache.register(path.clone(), Some(artifact.hir), builder.pop_mod_ctx());
             }
-            Err((maybe_hir, errs)) => {
-                if let Some(hir) = maybe_hir {
+            Err(artifact) => {
+                if let Some(hir) = artifact.hir {
                     mod_cache.register(path, Some(hir), builder.pop_mod_ctx());
                 }
-                return Err(errs);
+                return Err(artifact.errors);
             }
         }
         Ok(path)
@@ -1168,15 +1168,15 @@ impl Context {
             py_mod_cache.clone(),
         );
         match builder.build(src, "declare") {
-            Ok(hir) => {
+            Ok(artifact) => {
                 let ctx = builder.pop_mod_ctx();
-                py_mod_cache.register(path.clone(), Some(hir), ctx);
+                py_mod_cache.register(path.clone(), Some(artifact.hir), ctx);
             }
-            Err((maybe_hir, errs)) => {
-                if let Some(hir) = maybe_hir {
+            Err(artifact) => {
+                if let Some(hir) = artifact.hir {
                     py_mod_cache.register(path, Some(hir), builder.pop_mod_ctx());
                 }
-                return Err(errs);
+                return Err(artifact.errors);
             }
         }
         Ok(path)
diff --git a/compiler/erg_compiler/lib.rs b/compiler/erg_compiler/lib.rs
index 19740e29..d3013842 100644
--- a/compiler/erg_compiler/lib.rs
+++ b/compiler/erg_compiler/lib.rs
@@ -3,6 +3,7 @@
 extern crate erg_common;
 pub extern crate erg_parser;
 
+pub mod artifact;
 pub mod build_hir;
 mod compile;
 pub use compile::*;
diff --git a/compiler/erg_compiler/lower.rs b/compiler/erg_compiler/lower.rs
index e5fd47fd..9a8a5458 100644
--- a/compiler/erg_compiler/lower.rs
+++ b/compiler/erg_compiler/lower.rs
@@ -18,6 +18,7 @@ use erg_parser::build_ast::ASTBuilder;
 use erg_parser::token::{Token, TokenKind};
 use erg_parser::Parser;
 
+use crate::artifact::{CompleteArtifact, IncompleteArtifact};
 use crate::context::instantiate::TyVarCache;
 use crate::ty::constructors::{
     array_mut, array_t, free_var, func, mono, poly, proc, set_mut, set_t, ty_tp,
@@ -90,19 +91,23 @@ impl Runnable for ASTLowerer {
     fn exec(&mut self) -> Result<i32, Self::Errs> {
         let mut ast_builder = ASTBuilder::new(self.cfg.copy());
         let ast = ast_builder.build(self.input().read())?;
-        let (hir, warns) = self.lower(ast, "exec").map_err(|(_, errs)| errs)?;
+        let artifact = self
+            .lower(ast, "exec")
+            .map_err(|artifact| artifact.errors)?;
         if self.cfg.verbose >= 2 {
-            warns.fmt_all_stderr();
+            artifact.warns.fmt_all_stderr();
         }
-        println!("{hir}");
+        println!("{}", artifact.hir);
         Ok(0)
     }
 
     fn eval(&mut self, src: String) -> Result<String, Self::Errs> {
         let mut ast_builder = ASTBuilder::new(self.cfg.copy());
         let ast = ast_builder.build(src)?;
-        let (hir, ..) = self.lower(ast, "eval").map_err(|(_, errs)| errs)?;
-        Ok(format!("{hir}"))
+        let artifact = self
+            .lower(ast, "eval")
+            .map_err(|artifact| artifact.errors)?;
+        Ok(format!("{}", artifact.hir))
     }
 }
 
@@ -1781,25 +1786,30 @@ impl ASTLowerer {
         HIR::new(ast.name, module)
     }
 
-    pub fn lower(
-        &mut self,
-        ast: AST,
-        mode: &str,
-    ) -> Result<(HIR, LowerWarnings), (Option<HIR>, LowerErrors)> {
+    pub fn lower(&mut self, ast: AST, mode: &str) -> Result<CompleteArtifact, IncompleteArtifact> {
         log!(info "the AST lowering process has started.");
         log!(info "the type-checking process has started.");
         let ast = Reorderer::new(self.cfg.clone())
             .reorder(ast)
-            .map_err(|errs| (None, errs))?;
+            .map_err(|errs| {
+                IncompleteArtifact::new(None, errs, LowerWarnings::from(self.warns.take_all()))
+            })?;
         if mode == "declare" {
             let hir = self.declare_module(ast);
             if self.errs.is_empty() {
                 log!(info "HIR:\n{hir}");
                 log!(info "the declaring process has completed.");
-                return Ok((hir, LowerWarnings::from(self.warns.take_all())));
+                return Ok(CompleteArtifact::new(
+                    hir,
+                    LowerWarnings::from(self.warns.take_all()),
+                ));
             } else {
                 log!(err "the declaring process has failed.");
-                return Err((Some(hir), LowerErrors::from(self.errs.take_all())));
+                return Err(IncompleteArtifact::new(
+                    Some(hir),
+                    LowerErrors::from(self.errs.take_all()),
+                    LowerWarnings::from(self.warns.take_all()),
+                ));
             }
         }
         let mut module = hir::Module::with_capacity(ast.module.len());
@@ -1829,7 +1839,11 @@ impl ASTLowerer {
             Err((hir, errs)) => {
                 self.errs.extend(errs.into_iter());
                 log!(err "the resolving process has failed. errs:  {}", self.errs.len());
-                return Err((Some(hir), LowerErrors::from(self.errs.take_all())));
+                return Err(IncompleteArtifact::new(
+                    Some(hir),
+                    LowerErrors::from(self.errs.take_all()),
+                    LowerWarnings::from(self.warns.take_all()),
+                ));
             }
         };
         // TODO: recursive check
@@ -1840,10 +1854,17 @@ impl ASTLowerer {
         }
         if self.errs.is_empty() {
             log!(info "the AST lowering process has completed.");
-            Ok((hir, LowerWarnings::from(self.warns.take_all())))
+            Ok(CompleteArtifact::new(
+                hir,
+                LowerWarnings::from(self.warns.take_all()),
+            ))
         } else {
             log!(err "the AST lowering process has failed. errs: {}", self.errs.len());
-            Err((Some(hir), LowerErrors::from(self.errs.take_all())))
+            Err(IncompleteArtifact::new(
+                Some(hir),
+                LowerErrors::from(self.errs.take_all()),
+                LowerWarnings::from(self.warns.take_all()),
+            ))
         }
     }
 }