diff --git a/crates/ra_syntax/src/lib.rs b/crates/ra_syntax/src/lib.rs
index d02078256c..7f69b86e15 100644
--- a/crates/ra_syntax/src/lib.rs
+++ b/crates/ra_syntax/src/lib.rs
@@ -143,18 +143,17 @@ impl Parse<SourceFile> {
 pub use crate::ast::SourceFile;
 
 impl SourceFile {
-    fn new(green: GreenNode) -> SourceFile {
-        let root = SyntaxNode::new_root(green);
+    pub fn parse(text: &str) -> Parse<SourceFile> {
+        let (green, mut errors) = parsing::parse_text(text);
+        let root = SyntaxNode::new_root(green.clone());
+
         if cfg!(debug_assertions) {
             validation::validate_block_structure(&root);
         }
-        assert_eq!(root.kind(), SyntaxKind::SOURCE_FILE);
-        SourceFile::cast(root).unwrap()
-    }
 
-    pub fn parse(text: &str) -> Parse<SourceFile> {
-        let (green, mut errors) = parsing::parse_text(text);
-        errors.extend(validation::validate(&SourceFile::new(green.clone())));
+        errors.extend(validation::validate(&root));
+
+        assert_eq!(root.kind(), SyntaxKind::SOURCE_FILE);
         Parse { green, errors: Arc::new(errors), _ty: PhantomData }
     }
 }
diff --git a/crates/ra_syntax/src/validation.rs b/crates/ra_syntax/src/validation.rs
index 19bdafef22..e03c02d1ba 100644
--- a/crates/ra_syntax/src/validation.rs
+++ b/crates/ra_syntax/src/validation.rs
@@ -5,16 +5,16 @@ mod field_expr;
 
 use crate::{
     algo::visit::{visitor_ctx, VisitorCtx},
-    ast, AstNode, SourceFile, SyntaxError,
+    ast, SyntaxError,
     SyntaxKind::{BYTE, BYTE_STRING, CHAR, STRING},
     SyntaxNode, TextUnit, T,
 };
 
 pub(crate) use unescape::EscapeError;
 
-pub(crate) fn validate(file: &SourceFile) -> Vec<SyntaxError> {
+pub(crate) fn validate(root: &SyntaxNode) -> Vec<SyntaxError> {
     let mut errors = Vec::new();
-    for node in file.syntax().descendants() {
+    for node in root.descendants() {
         let _ = visitor_ctx(&mut errors)
             .visit::<ast::Literal, _>(validate_literal)
             .visit::<ast::Block, _>(block::validate_block_node)