diff --git a/crates/ra_mbe/src/lib.rs b/crates/ra_mbe/src/lib.rs
index 41720df79f56..a0904323cbb4 100644
--- a/crates/ra_mbe/src/lib.rs
+++ b/crates/ra_mbe/src/lib.rs
@@ -52,6 +52,9 @@ pub(crate) struct Rule {
 
 impl MacroRules {
     pub fn parse(tt: &tt::Subtree) -> Result<MacroRules, ParseError> {
+        // Note: this parsing can be implemented using mbe machinery itself, by
+        // matching against `$($lhs:tt => $rhs:tt);*` pattern, but implementing
+        // manually seems easier.
         let mut src = TtIter::new(tt);
         let mut rules = Vec::new();
         while src.len() > 0 {
@@ -64,6 +67,11 @@ impl MacroRules {
                 break;
             }
         }
+
+        for rule in rules.iter() {
+            validate(&rule.lhs)?;
+        }
+
         Ok(MacroRules { rules })
     }
     pub fn expand(&self, tt: &tt::Subtree) -> Result<tt::Subtree, ExpandError> {
@@ -77,7 +85,6 @@ impl Rule {
             .expect_subtree()
             .map_err(|()| ParseError::Expected("expected subtree".to_string()))?
             .clone();
-        validate(&lhs)?;
         lhs.delimiter = tt::Delimiter::None;
         src.expect_char('=').map_err(|()| ParseError::Expected("expected `=`".to_string()))?;
         src.expect_char('>').map_err(|()| ParseError::Expected("expected `>`".to_string()))?;
diff --git a/crates/ra_mbe/src/parser.rs b/crates/ra_mbe/src/parser.rs
index 575f587cf3ce..50b8011a909d 100644
--- a/crates/ra_mbe/src/parser.rs
+++ b/crates/ra_mbe/src/parser.rs
@@ -142,7 +142,6 @@ fn is_boolean_literal(lit: &tt::Literal) -> bool {
     }
 }
 
-///TOOD: impl for slice iter
 fn parse_repeat(src: &mut TtIter) -> Result<(Option<Separator>, RepeatKind), ExpandError> {
     let mut separator = Separator::Puncts(SmallVec::new());
     for tt in src {
diff --git a/crates/ra_tools/tests/cli.rs b/crates/ra_tools/tests/cli.rs
index c672e5788953..91b19c8f822a 100644
--- a/crates/ra_tools/tests/cli.rs
+++ b/crates/ra_tools/tests/cli.rs
@@ -34,7 +34,7 @@ fn no_todo() {
             return;
         }
         let text = std::fs::read_to_string(e.path()).unwrap();
-        if text.contains("TODO") {
+        if text.contains("TODO") || text.contains("TOOD") {
             panic!(
                 "\nTODO markers should not be commited to the master branch,\n\
                  use FIXME instead\n\