diff --git a/ergotree-interpreter/src/eval.rs b/ergotree-interpreter/src/eval.rs
index 1a5ebfcd5..dd9f03a9f 100644
--- a/ergotree-interpreter/src/eval.rs
+++ b/ergotree-interpreter/src/eval.rs
@@ -1,7 +1,7 @@
 //! Interpreter
 use bounded_vec::BoundedVecOutOfBounds;
 use ergotree_ir::mir::constant::TryExtractInto;
-use ergotree_ir::mir::expr::SourceSpan;
+use ergotree_ir::mir::expr::Span;
 use ergotree_ir::sigma_protocol::sigma_boolean::SigmaProp;
 use sigma_ser::ScorexParsingError;
 use sigma_ser::ScorexSerializationError;
@@ -170,13 +170,13 @@ pub enum EvalError {
         /// eval error
         error: Box<EvalError>,
         /// source span
-        source_span: SourceSpan,
+        source_span: Span,
     },
 }
 
 impl EvalError {
     /// Wrap eval error with source span
-    pub fn wrap_with_span(self, source_span: SourceSpan) -> Self {
+    pub fn wrap_with_span(self, source_span: Span) -> Self {
         EvalError::WrappedWithSpan {
             error: Box::new(self),
             source_span,
diff --git a/ergotree-interpreter/src/eval/expr.rs b/ergotree-interpreter/src/eval/expr.rs
index 8dd436445..074ec6bda 100644
--- a/ergotree-interpreter/src/eval/expr.rs
+++ b/ergotree-interpreter/src/eval/expr.rs
@@ -1,5 +1,5 @@
 use ergotree_ir::mir::expr::Expr;
-use ergotree_ir::mir::expr::SourceSpan;
+use ergotree_ir::mir::expr::Span;
 use ergotree_ir::mir::value::Value;
 
 use super::Env;
@@ -86,11 +86,11 @@ impl Evaluable for Expr {
 }
 
 pub trait ExtResultEvalError<T> {
-    fn with_span(self, span: &SourceSpan) -> Result<T, EvalError>;
+    fn with_span(self, span: &Span) -> Result<T, EvalError>;
 }
 
 impl<T> ExtResultEvalError<T> for Result<T, EvalError> {
-    fn with_span(self, span: &SourceSpan) -> Result<T, EvalError> {
+    fn with_span(self, span: &Span) -> Result<T, EvalError> {
         self.map_err(|e| e.wrap_with_span(span.clone()))
     }
 }
diff --git a/ergotree-ir/src/lib.rs b/ergotree-ir/src/lib.rs
index 9f81748ec..b2ac46230 100644
--- a/ergotree-ir/src/lib.rs
+++ b/ergotree-ir/src/lib.rs
@@ -28,6 +28,7 @@ pub mod ergo_tree;
 pub mod mir;
 pub mod serialization;
 pub mod sigma_protocol;
+pub mod source_span;
 pub mod type_check;
 pub mod types;
 pub mod util;
diff --git a/ergotree-ir/src/mir/expr.rs b/ergotree-ir/src/mir/expr.rs
index 7b1943e65..f59b0cbb1 100644
--- a/ergotree-ir/src/mir/expr.rs
+++ b/ergotree-ir/src/mir/expr.rs
@@ -3,6 +3,7 @@
 use std::convert::TryFrom;
 use std::convert::TryInto;
 
+use crate::source_span::Spanned;
 use crate::types::stype::LiftIntoSType;
 use crate::types::stype::SType;
 
@@ -80,14 +81,11 @@ use derive_more::From;
 use derive_more::TryInto;
 use thiserror::Error;
 
-mod source_span;
-pub use source_span::*;
-
 #[derive(PartialEq, Eq, Debug, Clone, From, TryInto)]
 /// Expression in ErgoTree
 pub enum Expr {
     /// Append - Concatenation of two collections
-    Append(SourceSpanWrapper<Append>),
+    Append(Spanned<Append>),
     /// Constant value
     Const(Constant),
     /// Placeholder for a constant
diff --git a/ergotree-ir/src/mir/expr/source_span.rs b/ergotree-ir/src/source_span.rs
similarity index 55%
rename from ergotree-ir/src/mir/expr/source_span.rs
rename to ergotree-ir/src/source_span.rs
index 07cac9179..6e1930a6b 100644
--- a/ergotree-ir/src/mir/expr/source_span.rs
+++ b/ergotree-ir/src/source_span.rs
@@ -1,33 +1,34 @@
-use crate::mir::coll_append::Append;
+//! Source position for an IR node in the source code
 
-use super::Expr;
+use crate::mir::coll_append::Append;
+use crate::mir::expr::Expr;
 
 /// Source position for the Expr
 #[derive(PartialEq, Eq, Debug, Clone)]
-pub struct SourceSpan {
+pub struct Span {
     /// Start position in the source code
     pub start: usize,
     /// End position in the source code
     pub end: usize,
 }
 
-impl SourceSpan {
+impl Span {
     /// Empty span
     pub fn empty() -> Self {
-        SourceSpan { start: 0, end: 0 }
+        Span { start: 0, end: 0 }
     }
 }
 
 /// Wrapper for Expr with source position
 #[derive(PartialEq, Eq, Debug, Clone)]
-pub struct SourceSpanWrapper<T> {
+pub struct Spanned<T> {
     /// Source position
-    pub source_span: SourceSpan,
+    pub source_span: Span,
     /// Wrapped value
     pub expr: T,
 }
 
-impl<T> SourceSpanWrapper<T> {
+impl<T> Spanned<T> {
     /// Expression
     pub fn expr(&self) -> &T {
         &self.expr
@@ -37,21 +38,18 @@ impl<T> SourceSpanWrapper<T> {
 // TODO: can be a macros
 impl From<Append> for Expr {
     fn from(v: Append) -> Self {
-        Expr::Append(SourceSpanWrapper {
-            source_span: SourceSpan::empty(),
+        Expr::Append(Spanned {
+            source_span: Span::empty(),
             expr: v,
         })
     }
 }
 
-impl<T> From<T> for SourceSpanWrapper<T> {
+impl<T> From<T> for Spanned<T> {
     fn from(v: T) -> Self {
-        SourceSpanWrapper {
-            source_span: SourceSpan::empty(),
+        Spanned {
+            source_span: Span::empty(),
             expr: v,
         }
     }
 }
-
-// TODO: draft pretty printer and how it's sets source span for every expr
-// TODO: draft enriching eval errors with source span and hightlight it in the source code piece