diff --git a/crates/ra_hir/src/macros.rs b/crates/ra_hir/src/macros.rs
index c23ad53cc4..4740e53374 100644
--- a/crates/ra_hir/src/macros.rs
+++ b/crates/ra_hir/src/macros.rs
@@ -250,3 +250,29 @@ fn convert_tt(tt: &SyntaxNode) -> Option<tt::Subtree> {
     };
     Some(res)
 }
+
+#[test]
+fn test_convert_tt() {
+    let text = r#"
+macro_rules! impl_froms {
+    ($e:ident: $($v:ident), *) => {
+        $(
+            impl From<$v> for $e {
+                fn from(it: $v) -> $e {
+                    $e::$v(it)
+                }
+            }
+        )*
+    }
+}
+"#;
+    let source_file = ast::SourceFile::parse(text);
+    let maco_call = source_file
+        .syntax()
+        .descendants()
+        .find_map(ast::MacroCall::cast)
+        .unwrap();
+    let tt = macro_call_to_tt(maco_call).unwrap();
+    let tt = mbe::parse(&tt);
+    dbg!(tt);
+}
diff --git a/crates/ra_hir/src/macros/mbe.rs b/crates/ra_hir/src/macros/mbe.rs
index 1408ed511b..7af7066fb8 100644
--- a/crates/ra_hir/src/macros/mbe.rs
+++ b/crates/ra_hir/src/macros/mbe.rs
@@ -2,21 +2,25 @@ use ra_syntax::SmolStr;
 
 use crate::macros::tt;
 
-struct MacroRules {
+#[derive(Debug)]
+pub(crate) struct MacroRules {
     rules: Vec<Rule>,
 }
 
+#[derive(Debug)]
 struct Rule {
     lhs: TokenTree,
     rhs: TokenTree,
 }
 
+#[derive(Debug)]
 enum TokenTree {
     Leaf(Leaf),
     Subtree(Subtree),
     Repeat(Repeat),
 }
 
+#[derive(Debug)]
 enum Leaf {
     Literal(Literal),
     Punct(Punct),
@@ -24,11 +28,13 @@ enum Leaf {
     Var(Var),
 }
 
+#[derive(Debug)]
 struct Subtree {
     delimiter: Delimiter,
     token_trees: Vec<TokenTree>,
 }
 
+#[derive(Debug)]
 enum Delimiter {
     Parenthesis,
     Brace,
@@ -36,33 +42,39 @@ enum Delimiter {
     None,
 }
 
+#[derive(Debug)]
 struct Repeat {
     subtree: Subtree,
     kind: RepeatKind,
 }
 
+#[derive(Debug)]
 enum RepeatKind {
     ZeroOrMore,
     OneOrMore,
     ZeroOrOne,
 }
 
+#[derive(Debug)]
 struct Literal {
     text: SmolStr,
 }
 
+#[derive(Debug)]
 struct Punct {
     char: char,
 }
 
+#[derive(Debug)]
 struct Ident {
     text: SmolStr,
 }
 
+#[derive(Debug)]
 struct Var {
     text: SmolStr,
 }
 
-fn parse(tt: tt::TokenTree) -> MacroRules {
+pub(crate) fn parse(tt: &tt::Subtree) -> MacroRules {
     MacroRules { rules: Vec::new() }
 }
diff --git a/crates/ra_hir/src/macros/tt.rs b/crates/ra_hir/src/macros/tt.rs
index 11b1089d36..02ff422b5f 100644
--- a/crates/ra_hir/src/macros/tt.rs
+++ b/crates/ra_hir/src/macros/tt.rs
@@ -1,11 +1,13 @@
 use ra_syntax::SmolStr;
 
+#[derive(Debug)]
 pub(crate) enum TokenTree {
     Leaf(Leaf),
     Subtree(Subtree),
 }
 impl_froms!(TokenTree: Leaf, Subtree);
 
+#[derive(Debug)]
 pub(crate) enum Leaf {
     Literal(Literal),
     Punct(Punct),
@@ -13,11 +15,13 @@ pub(crate) enum Leaf {
 }
 impl_froms!(Leaf: Literal, Punct, Ident);
 
+#[derive(Debug)]
 pub(crate) struct Subtree {
     pub(crate) delimiter: Delimiter,
     pub(crate) token_trees: Vec<TokenTree>,
 }
 
+#[derive(Debug)]
 pub(crate) enum Delimiter {
     Parenthesis,
     Brace,
@@ -25,14 +29,17 @@ pub(crate) enum Delimiter {
     None,
 }
 
+#[derive(Debug)]
 pub(crate) struct Literal {
     pub(crate) text: SmolStr,
 }
 
+#[derive(Debug)]
 pub(crate) struct Punct {
     pub(crate) char: char,
 }
 
+#[derive(Debug)]
 pub(crate) struct Ident {
     pub(crate) text: SmolStr,
 }