diff --git a/nac3artiq/src/symbol_resolver.rs b/nac3artiq/src/symbol_resolver.rs
index 6ef6e951f..2bb2751c6 100644
--- a/nac3artiq/src/symbol_resolver.rs
+++ b/nac3artiq/src/symbol_resolver.rs
@@ -9,7 +9,7 @@ use nac3core::{
     },
     typecheck::{
         type_inferencer::PrimitiveStore,
-        typedef::{iter_type_vars, to_var_map, Type, TypeEnum, TypeVar, Unifier, VarMap},
+        typedef::{iter_type_vars, into_var_map, Type, TypeEnum, TypeVar, Unifier, VarMap},
     },
 };
 use nac3parser::ast::{self, StrRef};
@@ -719,7 +719,7 @@ impl InnerResolver {
                         unreachable!("must be tobj")
                     };
 
-                    let var_map = to_var_map(iter_type_vars(params).map(|tvar| {
+                    let var_map = into_var_map(iter_type_vars(params).map(|tvar| {
                         let TypeEnum::TVar { id, range, name, loc, .. } = &*unifier.get_ty(tvar.ty)
                         else {
                             unreachable!()
@@ -746,7 +746,7 @@ impl InnerResolver {
             }
             (TypeEnum::TObj { params, fields, .. }, false) => {
                 self.pyid_to_type.write().insert(py_obj_id, extracted_ty);
-                let var_map = to_var_map(iter_type_vars(params).map(|tvar| {
+                let var_map = into_var_map(iter_type_vars(params).map(|tvar| {
                     let TypeEnum::TVar { id, range, name, loc, .. } = &*unifier.get_ty(tvar.ty)
                     else {
                         unreachable!()
diff --git a/nac3core/src/codegen/concrete_type.rs b/nac3core/src/codegen/concrete_type.rs
index 7ac198a40..65cbe570b 100644
--- a/nac3core/src/codegen/concrete_type.rs
+++ b/nac3core/src/codegen/concrete_type.rs
@@ -3,7 +3,7 @@ use crate::{
     toplevel::DefinitionId,
     typecheck::{
         type_inferencer::PrimitiveStore,
-        typedef::{to_var_map, FunSignature, FuncArg, Type, TypeEnum, TypeVar, TypeVarId, Unifier},
+        typedef::{into_var_map, FunSignature, FuncArg, Type, TypeEnum, TypeVar, TypeVarId, Unifier},
     },
 };
 
@@ -272,7 +272,7 @@ impl ConcreteTypeStore {
                         (*name, (self.to_unifier_type(unifier, primitives, cty.0, cache), cty.1))
                     })
                     .collect::<HashMap<_, _>>(),
-                params: to_var_map(params.iter().map(|(&id, cty)| {
+                params: into_var_map(params.iter().map(|(&id, cty)| {
                     let ty = self.to_unifier_type(unifier, primitives, *cty, cache);
                     TypeVar { id, ty }
                 })),
@@ -287,7 +287,7 @@ impl ConcreteTypeStore {
                     })
                     .collect(),
                 ret: self.to_unifier_type(unifier, primitives, *ret, cache),
-                vars: to_var_map(vars.iter().map(|(&id, cty)| {
+                vars: into_var_map(vars.iter().map(|(&id, cty)| {
                     let ty = self.to_unifier_type(unifier, primitives, *cty, cache);
                     TypeVar { id, ty }
                 })),
diff --git a/nac3core/src/toplevel/builtins.rs b/nac3core/src/toplevel/builtins.rs
index bfecd651b..e4b3ba0b8 100644
--- a/nac3core/src/toplevel/builtins.rs
+++ b/nac3core/src/toplevel/builtins.rs
@@ -25,7 +25,7 @@ use crate::{
     },
     symbol_resolver::SymbolValue,
     toplevel::{helper::PrimDef, numpy::make_ndarray_ty},
-    typecheck::typedef::{iter_type_vars, to_var_map, TypeVar, VarMap},
+    typecheck::typedef::{iter_type_vars, into_var_map, TypeVar, VarMap},
 };
 
 use super::*;
@@ -373,7 +373,7 @@ impl<'a> BuiltinBuilder<'a> {
             Some("N".into()),
             None,
         );
-        let num_var_map = to_var_map([num_ty]);
+        let num_var_map = into_var_map([num_ty]);
 
         let ndarray_float = make_ndarray_ty(unifier, primitives, Some(float), None);
         let ndarray_float_2d = {
@@ -390,11 +390,11 @@ impl<'a> BuiltinBuilder<'a> {
         let ndarray_num_ty = make_ndarray_ty(unifier, primitives, Some(num_ty.ty), None);
         let float_or_ndarray_ty =
             unifier.get_fresh_var_with_range(&[float, ndarray_float], Some("T".into()), None);
-        let float_or_ndarray_var_map = to_var_map([float_or_ndarray_ty]);
+        let float_or_ndarray_var_map = into_var_map([float_or_ndarray_ty]);
 
         let num_or_ndarray_ty =
             unifier.get_fresh_var_with_range(&[num_ty.ty, ndarray_num_ty], Some("T".into()), None);
-        let num_or_ndarray_var_map = to_var_map([num_ty, num_or_ndarray_ty]);
+        let num_or_ndarray_var_map = into_var_map([num_ty, num_or_ndarray_ty]);
 
         let list_int32 = unifier.add_ty(TypeEnum::TList { ty: int32 });
 
@@ -717,7 +717,7 @@ impl<'a> BuiltinBuilder<'a> {
                         default_value: None,
                     }],
                     ret: self.primitives.option,
-                    vars: to_var_map([self.option_tvar]),
+                    vars: into_var_map([self.option_tvar]),
                 })),
                 var_id: vec![self.option_tvar.id],
                 instance_to_symbol: HashMap::default(),
@@ -892,7 +892,7 @@ impl<'a> BuiltinBuilder<'a> {
 
         create_fn_by_codegen(
             self.unifier,
-            &to_var_map([common_ndim, p0_ty, ret_ty]),
+            &into_var_map([common_ndim, p0_ty, ret_ty]),
             prim.name(),
             ret_ty.ty,
             &[(p0_ty.ty, "n")],
@@ -956,7 +956,7 @@ impl<'a> BuiltinBuilder<'a> {
 
         create_fn_by_codegen(
             self.unifier,
-            &to_var_map([common_ndim, p0_ty, ret_ty]),
+            &into_var_map([common_ndim, p0_ty, ret_ty]),
             prim.name(),
             ret_ty.ty,
             &[(p0_ty.ty, "n")],
@@ -1034,7 +1034,7 @@ impl<'a> BuiltinBuilder<'a> {
                             },
                         ],
                         ret: ndarray,
-                        vars: to_var_map([tv]),
+                        vars: into_var_map([tv]),
                     })),
                     var_id: vec![tv.id],
                     instance_to_symbol: HashMap::default(),
@@ -1054,7 +1054,7 @@ impl<'a> BuiltinBuilder<'a> {
 
                 create_fn_by_codegen(
                     self.unifier,
-                    &to_var_map([tv]),
+                    &into_var_map([tv]),
                     prim.name(),
                     self.primitives.ndarray,
                     // We are using List[int32] here, as I don't know a way to specify an n-tuple bound on a
@@ -1333,7 +1333,7 @@ impl<'a> BuiltinBuilder<'a> {
             signature: self.unifier.add_ty(TypeEnum::TFunc(FunSignature {
                 args: vec![FuncArg { name: "ls".into(), ty: arg_ty.ty, default_value: None }],
                 ret: int32,
-                vars: to_var_map([tvar, arg_ty]),
+                vars: into_var_map([tvar, arg_ty]),
             })),
             var_id: Vec::default(),
             instance_to_symbol: HashMap::default(),
@@ -1516,7 +1516,7 @@ impl<'a> BuiltinBuilder<'a> {
                     .map(|p| FuncArg { name: p.1.into(), ty: p.0, default_value: None })
                     .collect(),
                 ret: ret_ty.ty,
-                vars: to_var_map([x1_ty, x2_ty, ret_ty]),
+                vars: into_var_map([x1_ty, x2_ty, ret_ty]),
             })),
             var_id: vec![x1_ty.id, x2_ty.id],
             instance_to_symbol: HashMap::default(),
@@ -1745,7 +1745,7 @@ impl<'a> BuiltinBuilder<'a> {
                     .map(|p| FuncArg { name: p.1.into(), ty: p.0, default_value: None })
                     .collect(),
                 ret: ret_ty.ty,
-                vars: to_var_map([x1_ty, x2_ty, ret_ty]),
+                vars: into_var_map([x1_ty, x2_ty, ret_ty]),
             })),
             var_id: vec![ret_ty.id],
             instance_to_symbol: HashMap::default(),
diff --git a/nac3core/src/toplevel/helper.rs b/nac3core/src/toplevel/helper.rs
index 8cc77a919..0c37d1e81 100644
--- a/nac3core/src/toplevel/helper.rs
+++ b/nac3core/src/toplevel/helper.rs
@@ -2,7 +2,7 @@ use std::convert::TryInto;
 
 use crate::symbol_resolver::SymbolValue;
 use crate::toplevel::numpy::unpack_ndarray_var_tys;
-use crate::typecheck::typedef::{to_var_map, Mapping, TypeVarId, VarMap};
+use crate::typecheck::typedef::{into_var_map, Mapping, TypeVarId, VarMap};
 use nac3parser::ast::{Constant, Location};
 use strum::IntoEnumIterator;
 use strum_macros::EnumIter;
@@ -377,12 +377,12 @@ impl TopLevelComposer {
         let is_some_type_fun_ty = unifier.add_ty(TypeEnum::TFunc(FunSignature {
             args: vec![],
             ret: bool,
-            vars: to_var_map([option_type_var]),
+            vars: into_var_map([option_type_var]),
         }));
         let unwrap_fun_ty = unifier.add_ty(TypeEnum::TFunc(FunSignature {
             args: vec![],
             ret: option_type_var.ty,
-            vars: to_var_map([option_type_var]),
+            vars: into_var_map([option_type_var]),
         }));
         let option = unifier.add_ty(TypeEnum::TObj {
             obj_id: PrimDef::Option.id(),
@@ -393,7 +393,7 @@ impl TopLevelComposer {
             ]
             .into_iter()
             .collect::<HashMap<_, _>>(),
-            params: to_var_map([option_type_var]),
+            params: into_var_map([option_type_var]),
         });
 
         let size_t_ty = match size_t {
@@ -409,7 +409,7 @@ impl TopLevelComposer {
         let ndarray_copy_fun_ty = unifier.add_ty(TypeEnum::TFunc(FunSignature {
             args: vec![],
             ret: ndarray_copy_fun_ret_ty.ty,
-            vars: to_var_map([ndarray_dtype_tvar, ndarray_ndims_tvar]),
+            vars: into_var_map([ndarray_dtype_tvar, ndarray_ndims_tvar]),
         }));
         let ndarray_fill_fun_ty = unifier.add_ty(TypeEnum::TFunc(FunSignature {
             args: vec![FuncArg {
@@ -418,7 +418,7 @@ impl TopLevelComposer {
                 default_value: None,
             }],
             ret: none,
-            vars: to_var_map([ndarray_dtype_tvar, ndarray_ndims_tvar]),
+            vars: into_var_map([ndarray_dtype_tvar, ndarray_ndims_tvar]),
         }));
         let ndarray = unifier.add_ty(TypeEnum::TObj {
             obj_id: PrimDef::NDArray.id(),
@@ -426,7 +426,7 @@ impl TopLevelComposer {
                 (PrimDef::NDArrayCopy.simple_name().into(), (ndarray_copy_fun_ty, true)),
                 (PrimDef::NDArrayFill.simple_name().into(), (ndarray_fill_fun_ty, true)),
             ]),
-            params: to_var_map([ndarray_dtype_tvar, ndarray_ndims_tvar]),
+            params: into_var_map([ndarray_dtype_tvar, ndarray_ndims_tvar]),
         });
 
         unifier.unify(ndarray_copy_fun_ret_ty.ty, ndarray).unwrap();
diff --git a/nac3core/src/typecheck/type_inferencer/test.rs b/nac3core/src/typecheck/type_inferencer/test.rs
index 45c978851..b5e2b1e0d 100644
--- a/nac3core/src/typecheck/type_inferencer/test.rs
+++ b/nac3core/src/typecheck/type_inferencer/test.rs
@@ -143,7 +143,7 @@ impl TestEnvironment {
         let ndarray = unifier.add_ty(TypeEnum::TObj {
             obj_id: PrimDef::NDArray.id(),
             fields: HashMap::new(),
-            params: to_var_map([ndarray_dtype_tvar, ndarray_ndims_tvar]),
+            params: into_var_map([ndarray_dtype_tvar, ndarray_ndims_tvar]),
         });
         let primitives = PrimitiveStore {
             int32,
@@ -323,7 +323,7 @@ impl TestEnvironment {
         let foo_ty = unifier.add_ty(TypeEnum::TObj {
             obj_id: DefinitionId(defs + 1),
             fields: [("a".into(), (tvar.ty, true))].iter().cloned().collect::<HashMap<_, _>>(),
-            params: to_var_map([tvar]),
+            params: into_var_map([tvar]),
         });
         top_level_defs.push(
             RwLock::new(TopLevelDef::Class {
@@ -345,7 +345,7 @@ impl TestEnvironment {
             unifier.add_ty(TypeEnum::TFunc(FunSignature {
                 args: vec![],
                 ret: foo_ty,
-                vars: to_var_map([tvar]),
+                vars: into_var_map([tvar]),
             })),
         );
 
diff --git a/nac3core/src/typecheck/typedef/mod.rs b/nac3core/src/typecheck/typedef/mod.rs
index ee06cabd9..59e1ad415 100644
--- a/nac3core/src/typecheck/typedef/mod.rs
+++ b/nac3core/src/typecheck/typedef/mod.rs
@@ -61,7 +61,7 @@ pub type VarMap = IndexMapping<TypeVarId>;
 /// Build a [`VarMap`] from an iterator of [`TypeVar`]
 ///
 /// The resulting [`VarMap`] wil have the same order as the input iterator.
-pub fn to_var_map<I>(vars: I) -> VarMap
+pub fn into_var_map<I>(vars: I) -> VarMap
 where
     I: IntoIterator<Item = TypeVar>,
 {
diff --git a/nac3core/src/typecheck/typedef/test.rs b/nac3core/src/typecheck/typedef/test.rs
index 6867819aa..7c5dd47b9 100644
--- a/nac3core/src/typecheck/typedef/test.rs
+++ b/nac3core/src/typecheck/typedef/test.rs
@@ -116,7 +116,7 @@ impl TestEnvironment {
             unifier.add_ty(TypeEnum::TObj {
                 obj_id: DefinitionId(3),
                 fields: [("a".into(), (tvar.ty, true))].iter().cloned().collect::<HashMap<_, _>>(),
-                params: to_var_map([tvar]),
+                params: into_var_map([tvar]),
             }),
         );