10 files changed, 103 insertions, 81 deletions

diff --git a/crates/ra_db/src/lib.rs b/crates/ra_db/src/lib.rs
index 11e18a03d..b82d1bda0 100644
--- a/crates/ra_db/src/lib.rs
+++ b/crates/ra_db/src/lib.rs
@@ -5,7 +5,7 @@ mod input;
 use std::{panic, sync::Arc};
 
 use ra_prof::profile;
-use ra_syntax::{Parse, SourceFile, TextRange, TextUnit};
+use ra_syntax::{ast, Parse, SourceFile, TextRange, TextUnit};
 use relative_path::RelativePathBuf;
 
 pub use crate::{
@@ -74,7 +74,7 @@ pub trait SourceDatabase: CheckCanceled + std::fmt::Debug {
     fn file_text(&self, file_id: FileId) -> Arc<String>;
     // Parses the file into the syntax tree.
     #[salsa::invoke(parse_query)]
-    fn parse(&self, file_id: FileId) -> Parse;
+    fn parse(&self, file_id: FileId) -> Parse<ast::SourceFile>;
     /// Path to a file, relative to the root of its source root.
     #[salsa::input]
     fn file_relative_path(&self, file_id: FileId) -> RelativePathBuf;
@@ -98,7 +98,7 @@ fn source_root_crates(db: &impl SourceDatabase, id: SourceRootId) -> Arc<Vec<Cra
     Arc::new(res)
 }
 
-fn parse_query(db: &impl SourceDatabase, file_id: FileId) -> Parse {
+fn parse_query(db: &impl SourceDatabase, file_id: FileId) -> Parse<ast::SourceFile> {
     let _p = profile("parse_query");
     let text = db.file_text(file_id);
     SourceFile::parse(&*text)
diff --git a/crates/ra_hir/src/db.rs b/crates/ra_hir/src/db.rs
index 040c782e6..da9f3e32d 100644
--- a/crates/ra_hir/src/db.rs
+++ b/crates/ra_hir/src/db.rs
@@ -2,7 +2,7 @@ use std::sync::Arc;
 
 use parking_lot::Mutex;
 use ra_db::{salsa, SourceDatabase};
-use ra_syntax::{ast, SmolStr, SyntaxNode, TreeArc};
+use ra_syntax::{ast, Parse, SmolStr, SyntaxNode, TreeArc};
 
 use crate::{
     adt::{EnumData, StructData},
@@ -69,7 +69,7 @@ pub trait AstDatabase: InternDatabase {
     fn parse_or_expand(&self, file_id: HirFileId) -> Option<TreeArc<SyntaxNode>>;
 
     #[salsa::invoke(crate::ids::HirFileId::parse_macro_query)]
-    fn parse_macro(&self, macro_file: ids::MacroFile) -> Option<TreeArc<SyntaxNode>>;
+    fn parse_macro(&self, macro_file: ids::MacroFile) -> Option<Parse<SyntaxNode>>;
 
     #[salsa::invoke(crate::ids::macro_def_query)]
     fn macro_def(&self, macro_id: MacroDefId) -> Option<Arc<mbe::MacroRules>>;
diff --git a/crates/ra_hir/src/ids.rs b/crates/ra_hir/src/ids.rs
index 80e9cccd6..83f5c3f39 100644
--- a/crates/ra_hir/src/ids.rs
+++ b/crates/ra_hir/src/ids.rs
@@ -6,7 +6,7 @@ use std::{
 use mbe::MacroRules;
 use ra_db::{salsa, FileId};
 use ra_prof::profile;
-use ra_syntax::{ast, AstNode, SyntaxNode, TreeArc};
+use ra_syntax::{ast, AstNode, Parse, SyntaxNode, TreeArc};
 
 use crate::{AstDatabase, AstId, DefDatabase, FileAstId, InternDatabase, Module, Source};
 
@@ -61,14 +61,16 @@ impl HirFileId {
     ) -> Option<TreeArc<SyntaxNode>> {
         match file_id.0 {
             HirFileIdRepr::File(file_id) => Some(db.parse(file_id).tree().syntax().to_owned()),
-            HirFileIdRepr::Macro(macro_file) => db.parse_macro(macro_file),
+            HirFileIdRepr::Macro(macro_file) => {
+                db.parse_macro(macro_file).map(|it| it.tree().to_owned())
+            }
         }
     }
 
     pub(crate) fn parse_macro_query(
         db: &impl AstDatabase,
         macro_file: MacroFile,
-    ) -> Option<TreeArc<SyntaxNode>> {
+    ) -> Option<Parse<SyntaxNode>> {
         let _p = profile("parse_macro_query");
         let macro_call_id = macro_file.macro_call_id;
         let tt = db
@@ -85,10 +87,8 @@ impl HirFileId {
             })
             .ok()?;
         match macro_file.macro_file_kind {
-            MacroFileKind::Items => Some(mbe::token_tree_to_ast_item_list(&tt).syntax().to_owned()),
-            MacroFileKind::Expr => {
-                mbe::token_tree_to_expr(&tt).ok().map(|it| it.syntax().to_owned())
-            }
+            MacroFileKind::Items => Some(Parse::to_syntax(mbe::token_tree_to_ast_item_list(&tt))),
+            MacroFileKind::Expr => mbe::token_tree_to_expr(&tt).ok().map(Parse::to_syntax),
         }
     }
 }
diff --git a/crates/ra_ide_api/src/completion/completion_context.rs b/crates/ra_ide_api/src/completion/completion_context.rs
index f6584cdd6..4aa84751f 100644
--- a/crates/ra_ide_api/src/completion/completion_context.rs
+++ b/crates/ra_ide_api/src/completion/completion_context.rs
@@ -43,7 +43,7 @@ pub(crate) struct CompletionContext<'a> {
 impl<'a> CompletionContext<'a> {
     pub(super) fn new(
         db: &'a db::RootDatabase,
-        original_parse: &'a Parse,
+        original_parse: &'a Parse<ast::SourceFile>,
         position: FilePosition,
     ) -> Option<CompletionContext<'a>> {
         let module = source_binder::module_from_position(db, position);
@@ -83,7 +83,7 @@ impl<'a> CompletionContext<'a> {
         }
     }
 
-    fn fill(&mut self, original_parse: &'a Parse, offset: TextUnit) {
+    fn fill(&mut self, original_parse: &'a Parse<ast::SourceFile>, offset: TextUnit) {
         // Insert a fake ident to get a valid parse tree. We will use this file
         // to determine context, though the original_file will be used for
         // actual completion.
diff --git a/crates/ra_ide_api/src/status.rs b/crates/ra_ide_api/src/status.rs
index ce27f5ae2..a31e15245 100644
--- a/crates/ra_ide_api/src/status.rs
+++ b/crates/ra_ide_api/src/status.rs
@@ -9,7 +9,7 @@ use ra_db::{
     FileTextQuery, SourceRootId,
 };
 use ra_prof::{memory_usage, Bytes};
-use ra_syntax::{AstNode, Parse, SyntaxNode, TreeArc};
+use ra_syntax::{ast, AstNode, Parse, SyntaxNode};
 
 use crate::{
     db::RootDatabase,
@@ -79,10 +79,10 @@ impl fmt::Display for SyntaxTreeStats {
     }
 }
 
-impl FromIterator<TableEntry<FileId, Parse>> for SyntaxTreeStats {
+impl FromIterator<TableEntry<FileId, Parse<ast::SourceFile>>> for SyntaxTreeStats {
     fn from_iter<T>(iter: T) -> SyntaxTreeStats
     where
-        T: IntoIterator<Item = TableEntry<FileId, Parse>>,
+        T: IntoIterator<Item = TableEntry<FileId, Parse<ast::SourceFile>>>,
     {
         let mut res = SyntaxTreeStats::default();
         for entry in iter {
@@ -96,15 +96,15 @@ impl FromIterator<TableEntry<FileId, Parse>> for SyntaxTreeStats {
     }
 }
 
-impl FromIterator<TableEntry<MacroFile, Option<TreeArc<SyntaxNode>>>> for SyntaxTreeStats {
+impl FromIterator<TableEntry<MacroFile, Option<Parse<SyntaxNode>>>> for SyntaxTreeStats {
     fn from_iter<T>(iter: T) -> SyntaxTreeStats
     where
-        T: IntoIterator<Item = TableEntry<MacroFile, Option<TreeArc<SyntaxNode>>>>,
+        T: IntoIterator<Item = TableEntry<MacroFile, Option<Parse<SyntaxNode>>>>,
     {
         let mut res = SyntaxTreeStats::default();
         for entry in iter {
             res.total += 1;
-            if let Some(tree) = entry.value.and_then(|it| it) {
+            if let Some(tree) = entry.value.and_then(|it| it).map(|it| it.tree().to_owned()) {
                 res.retained += 1;
                 res.retained_size += tree.memory_size_of_subtree();
             }
diff --git a/crates/ra_ide_api/src/symbol_index.rs b/crates/ra_ide_api/src/symbol_index.rs
index 1f2ba954e..9b3a45319 100644
--- a/crates/ra_ide_api/src/symbol_index.rs
+++ b/crates/ra_ide_api/src/symbol_index.rs
@@ -169,7 +169,9 @@ impl SymbolIndex {
         self.map.as_fst().size() + self.symbols.len() * mem::size_of::<FileSymbol>()
     }
 
-    pub(crate) fn for_files(files: impl ParallelIterator<Item = (FileId, Parse)>) -> SymbolIndex {
+    pub(crate) fn for_files(
+        files: impl ParallelIterator<Item = (FileId, Parse<ast::SourceFile>)>,
+    ) -> SymbolIndex {
         let symbols = files
             .flat_map(|(file_id, file)| source_file_to_file_symbols(file.tree(), file_id))
             .collect::<Vec<_>>();
diff --git a/crates/ra_mbe/src/syntax_bridge.rs b/crates/ra_mbe/src/syntax_bridge.rs
index 7560d215a..bfc351f81 100644
--- a/crates/ra_mbe/src/syntax_bridge.rs
+++ b/crates/ra_mbe/src/syntax_bridge.rs
@@ -2,8 +2,8 @@ use crate::subtree_source::SubtreeTokenSource;
 use crate::ExpandError;
 use ra_parser::{ParseError, TreeSink};
 use ra_syntax::{
-    ast, AstNode, SmolStr, SyntaxElement, SyntaxKind, SyntaxKind::*, SyntaxNode, SyntaxTreeBuilder,
-    TextRange, TextUnit, TreeArc, T,
+    ast, AstNode, Parse, SmolStr, SyntaxElement, SyntaxKind, SyntaxKind::*, SyntaxNode,
+    SyntaxTreeBuilder, TextRange, TextUnit, T,
 };
 use tt::buffer::{Cursor, TokenBuffer};
 
@@ -45,7 +45,7 @@ pub fn syntax_node_to_token_tree(node: &SyntaxNode) -> Option<(tt::Subtree, Toke
 //
 //
 
-fn token_tree_to_syntax_node<F>(tt: &tt::Subtree, f: F) -> Result<TreeArc<SyntaxNode>, ExpandError>
+fn token_tree_to_syntax_node<F>(tt: &tt::Subtree, f: F) -> Result<Parse<SyntaxNode>, ExpandError>
 where
     F: Fn(&mut dyn ra_parser::TokenSource, &mut dyn ra_parser::TreeSink),
 {
@@ -58,50 +58,44 @@ where
         return Err(ExpandError::ConversionError);
     }
     //FIXME: would be cool to report errors
-    let (tree, _errors) = tree_sink.inner.finish();
-    Ok(tree)
+    let parse = tree_sink.inner.finish();
+    Ok(parse)
 }
 
 /// Parses the token tree (result of macro expansion) to an expression
-pub fn token_tree_to_expr(tt: &tt::Subtree) -> Result<TreeArc<ast::Expr>, ExpandError> {
-    let syntax = token_tree_to_syntax_node(tt, ra_parser::parse_expr)?;
-    ast::Expr::cast(&syntax)
-        .map(|m| m.to_owned())
-        .ok_or_else(|| crate::ExpandError::ConversionError)
+pub fn token_tree_to_expr(tt: &tt::Subtree) -> Result<Parse<ast::Expr>, ExpandError> {
+    let parse = token_tree_to_syntax_node(tt, ra_parser::parse_expr)?;
+    parse.cast().ok_or_else(|| crate::ExpandError::ConversionError)
 }
 
 /// Parses the token tree (result of macro expansion) to a Pattern
-pub fn token_tree_to_pat(tt: &tt::Subtree) -> Result<TreeArc<ast::Pat>, ExpandError> {
-    let syntax = token_tree_to_syntax_node(tt, ra_parser::parse_pat)?;
-    ast::Pat::cast(&syntax).map(|m| m.to_owned()).ok_or_else(|| ExpandError::ConversionError)
+pub fn token_tree_to_pat(tt: &tt::Subtree) -> Result<Parse<ast::Pat>, ExpandError> {
+    let parse = token_tree_to_syntax_node(tt, ra_parser::parse_pat)?;
+    parse.cast().ok_or_else(|| crate::ExpandError::ConversionError)
 }
 
 /// Parses the token tree (result of macro expansion) to a Type
-pub fn token_tree_to_ty(tt: &tt::Subtree) -> Result<TreeArc<ast::TypeRef>, ExpandError> {
-    let syntax = token_tree_to_syntax_node(tt, ra_parser::parse_ty)?;
-    ast::TypeRef::cast(&syntax).map(|m| m.to_owned()).ok_or_else(|| ExpandError::ConversionError)
+pub fn token_tree_to_ty(tt: &tt::Subtree) -> Result<Parse<ast::TypeRef>, ExpandError> {
+    let parse = token_tree_to_syntax_node(tt, ra_parser::parse_ty)?;
+    parse.cast().ok_or_else(|| crate::ExpandError::ConversionError)
 }
 
 /// Parses the token tree (result of macro expansion) as a sequence of stmts
-pub fn token_tree_to_macro_stmts(
-    tt: &tt::Subtree,
-) -> Result<TreeArc<ast::MacroStmts>, ExpandError> {
-    let syntax = token_tree_to_syntax_node(tt, ra_parser::parse_macro_stmts)?;
-    ast::MacroStmts::cast(&syntax).map(|m| m.to_owned()).ok_or_else(|| ExpandError::ConversionError)
+pub fn token_tree_to_macro_stmts(tt: &tt::Subtree) -> Result<Parse<ast::MacroStmts>, ExpandError> {
+    let parse = token_tree_to_syntax_node(tt, ra_parser::parse_macro_stmts)?;
+    parse.cast().ok_or_else(|| crate::ExpandError::ConversionError)
 }
 
 /// Parses the token tree (result of macro expansion) as a sequence of items
-pub fn token_tree_to_macro_items(
-    tt: &tt::Subtree,
-) -> Result<TreeArc<ast::MacroItems>, ExpandError> {
-    let syntax = token_tree_to_syntax_node(tt, ra_parser::parse_macro_items)?;
-    ast::MacroItems::cast(&syntax).map(|m| m.to_owned()).ok_or_else(|| ExpandError::ConversionError)
+pub fn token_tree_to_macro_items(tt: &tt::Subtree) -> Result<Parse<ast::MacroItems>, ExpandError> {
+    let parse = token_tree_to_syntax_node(tt, ra_parser::parse_macro_items)?;
+    parse.cast().ok_or_else(|| crate::ExpandError::ConversionError)
 }
 
 /// Parses the token tree (result of macro expansion) as a sequence of items
-pub fn token_tree_to_ast_item_list(tt: &tt::Subtree) -> TreeArc<ast::SourceFile> {
-    let syntax = token_tree_to_syntax_node(tt, ra_parser::parse).unwrap();
-    ast::SourceFile::cast(&syntax).unwrap().to_owned()
+pub fn token_tree_to_ast_item_list(tt: &tt::Subtree) -> Parse<ast::SourceFile> {
+    let parse = token_tree_to_syntax_node(tt, ra_parser::parse).unwrap();
+    parse.cast().unwrap()
 }
 
 impl TokenMap {
diff --git a/crates/ra_mbe/src/tests.rs b/crates/ra_mbe/src/tests.rs
index 5a1494fee..419b2c099 100644
--- a/crates/ra_mbe/src/tests.rs
+++ b/crates/ra_mbe/src/tests.rs
@@ -72,7 +72,7 @@ pub(crate) fn expand_to_items(
     invocation: &str,
 ) -> ra_syntax::TreeArc<ast::MacroItems> {
     let expanded = expand(rules, invocation);
-    token_tree_to_macro_items(&expanded).unwrap()
+    token_tree_to_macro_items(&expanded).unwrap().tree().to_owned()
 }
 
 #[allow(unused)]
@@ -81,7 +81,7 @@ pub(crate) fn expand_to_stmts(
     invocation: &str,
 ) -> ra_syntax::TreeArc<ast::MacroStmts> {
     let expanded = expand(rules, invocation);
-    token_tree_to_macro_stmts(&expanded).unwrap()
+    token_tree_to_macro_stmts(&expanded).unwrap().tree().to_owned()
 }
 
 pub(crate) fn expand_to_expr(
@@ -89,7 +89,7 @@ pub(crate) fn expand_to_expr(
     invocation: &str,
 ) -> ra_syntax::TreeArc<ast::Expr> {
     let expanded = expand(rules, invocation);
-    token_tree_to_expr(&expanded).unwrap()
+    token_tree_to_expr(&expanded).unwrap().tree().to_owned()
 }
 
 pub(crate) fn text_to_tokentree(text: &str) -> tt::Subtree {
@@ -164,22 +164,22 @@ pub(crate) fn assert_expansion(
 
     let (expanded_tree, expected_tree) = match kind {
         MacroKind::Items => {
-            let expanded_tree = token_tree_to_macro_items(&expanded);
-            let expected_tree = token_tree_to_macro_items(&expected);
+            let expanded_tree = token_tree_to_macro_items(&expanded).unwrap().tree().to_owned();
+            let expected_tree = token_tree_to_macro_items(&expected).unwrap().tree().to_owned();
 
             (
-                debug_dump_ignore_spaces(expanded_tree.unwrap().syntax()).trim().to_string(),
-                debug_dump_ignore_spaces(expected_tree.unwrap().syntax()).trim().to_string(),
+                debug_dump_ignore_spaces(expanded_tree.syntax()).trim().to_string(),
+                debug_dump_ignore_spaces(expected_tree.syntax()).trim().to_string(),
             )
         }
 
         MacroKind::Stmts => {
-            let expanded_tree = token_tree_to_macro_stmts(&expanded);
-            let expected_tree = token_tree_to_macro_stmts(&expected);
+            let expanded_tree = token_tree_to_macro_stmts(&expanded).unwrap().tree().to_owned();
+            let expected_tree = token_tree_to_macro_stmts(&expected).unwrap().tree().to_owned();
 
             (
-                debug_dump_ignore_spaces(expanded_tree.unwrap().syntax()).trim().to_string(),
-                debug_dump_ignore_spaces(expected_tree.unwrap().syntax()).trim().to_string(),
+                debug_dump_ignore_spaces(expanded_tree.syntax()).trim().to_string(),
+                debug_dump_ignore_spaces(expected_tree.syntax()).trim().to_string(),
             )
         }
     };
@@ -419,9 +419,9 @@ fn test_expand_to_item_list() {
             ",
     );
     let expansion = expand(&rules, "structs!(Foo, Bar);");
-    let tree = token_tree_to_macro_items(&expansion);
+    let tree = token_tree_to_macro_items(&expansion).unwrap().tree().to_owned();
     assert_eq!(
-        tree.unwrap().syntax().debug_dump().trim(),
+        tree.syntax().debug_dump().trim(),
         r#"
 MACRO_ITEMS@[0; 40)
   STRUCT_DEF@[0; 20)
@@ -537,10 +537,10 @@ fn test_tt_to_stmts() {
     );
 
     let expanded = expand(&rules, "foo!{}");
-    let stmts = token_tree_to_macro_stmts(&expanded);
+    let stmts = token_tree_to_macro_stmts(&expanded).unwrap().tree().to_owned();
 
     assert_eq!(
-        stmts.unwrap().syntax().debug_dump().trim(),
+        stmts.syntax().debug_dump().trim(),
         r#"MACRO_STMTS@[0; 15)
   LET_STMT@[0; 7)
     LET_KW@[0; 3) "let"
diff --git a/crates/ra_syntax/src/lib.rs b/crates/ra_syntax/src/lib.rs
index 0fa2fe382..534c206a6 100644
--- a/crates/ra_syntax/src/lib.rs
+++ b/crates/ra_syntax/src/lib.rs
@@ -43,8 +43,8 @@ pub use crate::{
     ptr::{AstPtr, SyntaxNodePtr},
     syntax_error::{Location, SyntaxError, SyntaxErrorKind},
     syntax_node::{
-        Direction, InsertPosition, SyntaxElement, SyntaxNode, SyntaxToken, SyntaxTreeBuilder,
-        TreeArc, WalkEvent,
+        Direction, InsertPosition, SyntaxElement, SyntaxNode, SyntaxNodeWrapper, SyntaxToken,
+        SyntaxTreeBuilder, TreeArc, WalkEvent,
     },
     syntax_text::SyntaxText,
 };
@@ -57,14 +57,24 @@ pub use rowan::{SmolStr, TextRange, TextUnit};
 ///
 /// Note that we always produce a syntax tree, even for completely invalid
 /// files.
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub struct Parse {
-    tree: TreeArc<SourceFile>,
+#[derive(Debug, PartialEq, Eq)]
+pub struct Parse<T: SyntaxNodeWrapper> {
+    tree: TreeArc<T>,
     errors: Arc<Vec<SyntaxError>>,
 }
 
-impl Parse {
-    pub fn tree(&self) -> &SourceFile {
+impl<T: SyntaxNodeWrapper> Clone for Parse<T> {
+    fn clone(&self) -> Parse<T> {
+        Parse { tree: self.tree.clone(), errors: self.errors.clone() }
+    }
+}
+
+impl<T: SyntaxNodeWrapper> Parse<T> {
+    fn new(tree: TreeArc<T>, errors: Vec<SyntaxError>) -> Parse<T> {
+        Parse { tree, errors: Arc::new(errors) }
+    }
+
+    pub fn tree(&self) -> &T {
         &*self.tree
     }
 
@@ -72,18 +82,22 @@ impl Parse {
         &*self.errors
     }
 
-    pub fn ok(self) -> Result<TreeArc<SourceFile>, Arc<Vec<SyntaxError>>> {
+    pub fn ok(self) -> Result<TreeArc<T>, Arc<Vec<SyntaxError>>> {
         if self.errors.is_empty() {
             Ok(self.tree)
         } else {
             Err(self.errors)
         }
     }
+}
 
-    pub fn reparse(&self, edit: &AtomTextEdit) -> Parse {
-        self.incremental_reparse(edit).unwrap_or_else(|| self.full_reparse(edit))
+impl<T: AstNode> Parse<T> {
+    pub fn to_syntax(this: Self) -> Parse<SyntaxNode> {
+        Parse { tree: this.tree().syntax().to_owned(), errors: this.errors }
     }
+}
 
+impl Parse<SourceFile> {
     pub fn debug_dump(&self) -> String {
         let mut buf = self.tree.syntax().debug_dump();
         for err in self.errors.iter() {
@@ -92,7 +106,11 @@ impl Parse {
         buf
     }
 
-    fn incremental_reparse(&self, edit: &AtomTextEdit) -> Option<Parse> {
+    pub fn reparse(&self, edit: &AtomTextEdit) -> Parse<SourceFile> {
+        self.incremental_reparse(edit).unwrap_or_else(|| self.full_reparse(edit))
+    }
+
+    fn incremental_reparse(&self, edit: &AtomTextEdit) -> Option<Parse<SourceFile>> {
         // FIXME: validation errors are not handled here
         parsing::incremental_reparse(self.tree.syntax(), edit, self.errors.to_vec()).map(
             |(green_node, errors, _reparsed_range)| Parse {
@@ -102,12 +120,19 @@ impl Parse {
         )
     }
 
-    fn full_reparse(&self, edit: &AtomTextEdit) -> Parse {
+    fn full_reparse(&self, edit: &AtomTextEdit) -> Parse<SourceFile> {
         let text = edit.apply(self.tree.syntax().text().to_string());
         SourceFile::parse(&text)
     }
 }
 
+impl Parse<SyntaxNode> {
+    pub fn cast<T: AstNode>(self) -> Option<Parse<T>> {
+        let node = T::cast(&self.tree)?;
+        Some(Parse { tree: node.to_owned(), errors: self.errors })
+    }
+}
+
 /// `SourceFile` represents a parse tree for a single Rust file.
 pub use crate::ast::SourceFile;
 
@@ -121,7 +146,7 @@ impl SourceFile {
         TreeArc::cast(root)
     }
 
-    pub fn parse(text: &str) -> Parse {
+    pub fn parse(text: &str) -> Parse<SourceFile> {
         let (green, mut errors) = parsing::parse_text(text);
         let tree = SourceFile::new(green);
         errors.extend(validation::validate(&tree));
diff --git a/crates/ra_syntax/src/syntax_node.rs b/crates/ra_syntax/src/syntax_node.rs
index a1f9a59b6..e57813a94 100644
--- a/crates/ra_syntax/src/syntax_node.rs
+++ b/crates/ra_syntax/src/syntax_node.rs
@@ -18,7 +18,8 @@ use rowan::{GreenNodeBuilder, TransparentNewType};
 
 use crate::{
     syntax_error::{SyntaxError, SyntaxErrorKind},
-    AstNode, SmolStr, SourceFile, SyntaxKind, SyntaxNodePtr, SyntaxText, TextRange, TextUnit,
+    AstNode, Parse, SmolStr, SourceFile, SyntaxKind, SyntaxNodePtr, SyntaxText, TextRange,
+    TextUnit,
 };
 
 pub use rowan::WalkEvent;
@@ -594,13 +595,13 @@ impl SyntaxTreeBuilder {
         (green, self.errors)
     }
 
-    pub fn finish(self) -> (TreeArc<SyntaxNode>, Vec<SyntaxError>) {
+    pub fn finish(self) -> Parse<SyntaxNode> {
         let (green, errors) = self.finish_raw();
         let node = SyntaxNode::new(green);
         if cfg!(debug_assertions) {
             crate::validation::validate_block_structure(&node);
         }
-        (node, errors)
+        Parse::new(node, errors)
     }
 
     pub fn token(&mut self, kind: SyntaxKind, text: SmolStr) {