10 files changed, 126 insertions, 81 deletions

diff --git a/crates/ra_editor/src/code_actions.rs b/crates/ra_editor/src/code_actions.rs
index 216d592ff..7b0a48c81 100644
--- a/crates/ra_editor/src/code_actions.rs
+++ b/crates/ra_editor/src/code_actions.rs
@@ -11,7 +11,7 @@ use ra_syntax::{
     },
 };
 
-use {EditBuilder, Edit, find_node_at_offset};
+use crate::{EditBuilder, Edit, find_node_at_offset};
 
 #[derive(Debug)]
 pub struct LocalEdit {
@@ -136,7 +136,7 @@ fn non_trivia_sibling(node: SyntaxNodeRef, direction: Direction) -> Option<Synta
 #[cfg(test)]
 mod tests {
     use super::*;
-    use test_utils::{check_action, check_action_range};
+    use crate::test_utils::{check_action, check_action_range};
 
     #[test]
     fn test_swap_comma() {
diff --git a/crates/ra_editor/src/completion.rs b/crates/ra_editor/src/completion.rs
index 20b8484b3..b6095dca9 100644
--- a/crates/ra_editor/src/completion.rs
+++ b/crates/ra_editor/src/completion.rs
@@ -9,7 +9,7 @@ use ra_syntax::{
     text_utils::is_subrange,
 };
 
-use {
+use crate::{
     AtomEdit, find_node_at_offset,
     scope::{FnScopes, ModuleScope},
 };
diff --git a/crates/ra_editor/src/edit.rs b/crates/ra_editor/src/edit.rs
index 2839ac20a..46e687319 100644
--- a/crates/ra_editor/src/edit.rs
+++ b/crates/ra_editor/src/edit.rs
@@ -1,4 +1,4 @@
-use {TextRange, TextUnit};
+use crate::{TextRange, TextUnit};
 use ra_syntax::{
     AtomEdit,
     text_utils::contains_offset_nonstrict,
diff --git a/crates/ra_editor/src/folding_ranges.rs b/crates/ra_editor/src/folding_ranges.rs
index 3aabd54ae..a1699d449 100644
--- a/crates/ra_editor/src/folding_ranges.rs
+++ b/crates/ra_editor/src/folding_ranges.rs
@@ -1,8 +1,10 @@
 use rustc_hash::FxHashSet;
 
 use ra_syntax::{
+    ast,
+    AstNode,
     File, TextRange, SyntaxNodeRef,
-    SyntaxKind,
+    SyntaxKind::{self, *},
     Direction,
 };
 
@@ -20,67 +22,97 @@ pub struct Fold {
 
 pub fn folding_ranges(file: &File) -> Vec<Fold> {
     let mut res = vec![];
-    let mut visited = FxHashSet::default();
+    let mut visited_comments = FxHashSet::default();
 
     for node in file.syntax().descendants() {
-        if visited.contains(&node) {
+        // Fold items that span multiple lines
+        if let Some(kind) = fold_kind(node.kind()) {
+            if has_newline(node) {
+                res.push(Fold { range: node.range(), kind });
+            }
+        }
+
+        // Also fold groups of comments
+        if visited_comments.contains(&node) {
             continue;
         }
+        if node.kind() == COMMENT {
+            contiguous_range_for_comment(node, &mut visited_comments)
+                .map(|range| res.push(Fold { range, kind: FoldKind::Comment }));
+        }
+    }
+
+    res
+}
 
-        let range_and_kind = match node.kind() {
-            SyntaxKind::COMMENT => (
-                contiguous_range_for(SyntaxKind::COMMENT, node, &mut visited),
-                Some(FoldKind::Comment),
-            ),
-            SyntaxKind::USE_ITEM => (
-                contiguous_range_for(SyntaxKind::USE_ITEM, node, &mut visited),
-                Some(FoldKind::Imports),
-            ),
-            _ => (None, None),
-        };
-
-        match range_and_kind {
-            (Some(range), Some(kind)) => {
-                res.push(Fold {
-                    range: range,
-                    kind: kind
-                });
+fn fold_kind(kind: SyntaxKind) -> Option<FoldKind> {
+    match kind {
+        COMMENT => Some(FoldKind::Comment),
+        USE_ITEM => Some(FoldKind::Imports),
+        _ => None
+    }
+}
+
+fn has_newline(
+    node: SyntaxNodeRef,
+) -> bool {
+    for descendant in node.descendants() {
+        if let Some(ws) = ast::Whitespace::cast(descendant) {
+            if ws.has_newlines() {
+                return true;
+            }
+        } else if let Some(comment) = ast::Comment::cast(descendant) {
+            if comment.has_newlines() {
+                return true;
             }
-            _ => {}
         }
     }
 
-    res
+    false
 }
 
-fn contiguous_range_for<'a>(
-    kind: SyntaxKind,
-    node: SyntaxNodeRef<'a>,
+fn contiguous_range_for_comment<'a>(
+    first: SyntaxNodeRef<'a>,
     visited: &mut FxHashSet<SyntaxNodeRef<'a>>,
 ) -> Option<TextRange> {
-    visited.insert(node);
-
-    let left = node;
-    let mut right = node;
-    for node in node.siblings(Direction::Next) {
-        visited.insert(node);
-        match node.kind() {
-            SyntaxKind::WHITESPACE if !node.leaf_text().unwrap().as_str().contains("\n\n") => (),
-            k => {
-                if k == kind {
-                    right = node
-                } else {
-                    break;
-                }
+    visited.insert(first);
+
+    // Only fold comments of the same flavor
+    let group_flavor = ast::Comment::cast(first)?.flavor();
+
+    let mut last = first;
+    for node in first.siblings(Direction::Next) {
+        if let Some(ws) = ast::Whitespace::cast(node) {
+            // There is a blank line, which means the group ends here
+            if ws.count_newlines_lazy().take(2).count() == 2 {
+                break;
+            }
+
+            // Ignore whitespace without blank lines
+            continue;
+        }
+
+        match ast::Comment::cast(node) {
+            Some(next_comment) if next_comment.flavor() == group_flavor => {
+                visited.insert(node);
+                last = node;
+            }
+            // The comment group ends because either:
+            // * An element of a different kind was reached
+            // * A comment of a different flavor was reached
+            _ => {
+                break
             }
         }
     }
-    if left != right {
+
+    if first != last {
         Some(TextRange::from_to(
-            left.range().start(),
-            right.range().end(),
+            first.range().start(),
+            last.range().end(),
         ))
     } else {
+        // The group consists of only one element, therefore it cannot be folded
         None
     }
 }
@@ -88,52 +120,65 @@ fn contiguous_range_for<'a>(
 #[cfg(test)]
 mod tests {
     use super::*;
+    use test_utils::extract_ranges;
+
+    fn do_check(text: &str, fold_kinds: &[FoldKind]) {
+        let (ranges, text) = extract_ranges(text);
+        let file = File::parse(&text);
+        let folds = folding_ranges(&file);
+
+        assert_eq!(folds.len(), ranges.len());
+        for ((fold, range), fold_kind) in folds.into_iter().zip(ranges.into_iter()).zip(fold_kinds.into_iter()) {
+            assert_eq!(fold.range.start(), range.start());
+            assert_eq!(fold.range.end(), range.end());
+            assert_eq!(&fold.kind, fold_kind);
+        }
+    }
 
     #[test]
     fn test_fold_comments() {
         let text = r#"
-// Hello
+<|>// Hello
 // this is a multiline
 // comment
-//
+//<|>
 
 // But this is not
 
 fn main() {
-    // We should
+    <|>// We should
     // also
     // fold
-    // this one.
+    // this one.<|>
+    <|>//! But this one is different
+    //! because it has another flavor<|>
+    <|>/* As does this
+    multiline comment */<|>
 }"#;
 
-        let file = File::parse(&text);
-        let folds = folding_ranges(&file);
-        assert_eq!(folds.len(), 2);
-        assert_eq!(folds[0].range.start(), 1.into());
-        assert_eq!(folds[0].range.end(), 46.into());
-        assert_eq!(folds[0].kind, FoldKind::Comment);
-
-        assert_eq!(folds[1].range.start(), 84.into());
-        assert_eq!(folds[1].range.end(), 137.into());
-        assert_eq!(folds[1].kind, FoldKind::Comment);
+        let fold_kinds = &[
+            FoldKind::Comment,
+            FoldKind::Comment,
+            FoldKind::Comment,
+            FoldKind::Comment,
+        ];
+        do_check(text, fold_kinds);
     }
 
     #[test]
     fn test_fold_imports() {
         let text = r#"
-use std::str;
-use std::vec;
-use std::io as iop;
+<|>use std::{
+    str,
+    vec,
+    io as iop
+};<|>
 
 fn main() {
 }"#;
 
-        let file = File::parse(&text);
-        let folds = folding_ranges(&file);
-        assert_eq!(folds.len(), 1);
-        assert_eq!(folds[0].range.start(), 1.into());
-        assert_eq!(folds[0].range.end(), 48.into());
-        assert_eq!(folds[0].kind, FoldKind::Imports);
+        let folds = &[FoldKind::Imports];
+        do_check(text, folds);
     }
 
 
diff --git a/crates/ra_editor/src/lib.rs b/crates/ra_editor/src/lib.rs
index 710afc65d..bd61fd191 100644
--- a/crates/ra_editor/src/lib.rs
+++ b/crates/ra_editor/src/lib.rs
@@ -164,7 +164,7 @@ pub fn resolve_local_name(file: &File, offset: TextUnit, name_ref: ast::NameRef)
 #[cfg(test)]
 mod tests {
     use super::*;
-    use test_utils::{assert_eq_dbg, extract_offset, add_cursor};
+    use crate::test_utils::{assert_eq_dbg, extract_offset, add_cursor};
 
     #[test]
     fn test_highlighting() {
diff --git a/crates/ra_editor/src/line_index.rs b/crates/ra_editor/src/line_index.rs
index 9cd8da3a8..95d64b8a8 100644
--- a/crates/ra_editor/src/line_index.rs
+++ b/crates/ra_editor/src/line_index.rs
@@ -1,7 +1,7 @@
 use superslice::Ext;
-use ::TextUnit;
+use crate::TextUnit;
 
-#[derive(Clone, Debug, Hash)]
+#[derive(Clone, Debug, Hash, PartialEq, Eq)]
 pub struct LineIndex {
     newlines: Vec<TextUnit>,
 }
diff --git a/crates/ra_editor/src/scope/fn_scope.rs b/crates/ra_editor/src/scope/fn_scope.rs
index 9a48bda02..99d698b60 100644
--- a/crates/ra_editor/src/scope/fn_scope.rs
+++ b/crates/ra_editor/src/scope/fn_scope.rs
@@ -174,7 +174,7 @@ fn compute_expr_scopes(expr: ast::Expr, scopes: &mut FnScopes, scope: ScopeId) {
             }
         }
         ast::Expr::LambdaExpr(e) => {
-            let mut scope = scopes.new_scope(scope);
+            let scope = scopes.new_scope(scope);
             scopes.add_params_bindings(scope, e.param_list());
             if let Some(body) = e.body() {
                 scopes.set_scope(body.syntax(), scope);
@@ -256,7 +256,7 @@ pub fn resolve_local_name<'a>(name_ref: ast::NameRef, scopes: &'a FnScopes) -> O
 mod tests {
     use super::*;
     use ra_syntax::File;
-    use {find_node_at_offset, test_utils::extract_offset};
+    use crate::{find_node_at_offset, test_utils::extract_offset};
 
     fn do_check(code: &str, expected: &[&str]) {
         let (off, code) = extract_offset(code);
diff --git a/crates/ra_editor/src/symbols.rs b/crates/ra_editor/src/symbols.rs
index e5cc5ca28..d9e4b2df7 100644
--- a/crates/ra_editor/src/symbols.rs
+++ b/crates/ra_editor/src/symbols.rs
@@ -6,7 +6,7 @@ use ra_syntax::{
         walk::{walk, WalkEvent},
     },
 };
-use TextRange;
+use crate::TextRange;
 
 #[derive(Debug, Clone)]
 pub struct StructureNode {
@@ -17,7 +17,7 @@ pub struct StructureNode {
     pub kind: SyntaxKind,
 }
 
-#[derive(Debug, Clone, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct FileSymbol {
     pub name: SmolStr,
     pub node_range: TextRange,
diff --git a/crates/ra_editor/src/test_utils.rs b/crates/ra_editor/src/test_utils.rs
index c4ea4db6c..49eb530d5 100644
--- a/crates/ra_editor/src/test_utils.rs
+++ b/crates/ra_editor/src/test_utils.rs
@@ -1,6 +1,6 @@
 use ra_syntax::{File, TextUnit, TextRange};
-pub use _test_utils::*;
-use LocalEdit;
+pub use crate::_test_utils::*;
+use crate::LocalEdit;
 
 pub fn check_action<F: Fn(&File, TextUnit) -> Option<LocalEdit>> (
     before: &str,
diff --git a/crates/ra_editor/src/typing.rs b/crates/ra_editor/src/typing.rs
index 1dc658f9b..542b9e10b 100644
--- a/crates/ra_editor/src/typing.rs
+++ b/crates/ra_editor/src/typing.rs
@@ -10,7 +10,7 @@ use ra_syntax::{
     SyntaxKind::*,
 };
 
-use {LocalEdit, EditBuilder, find_node_at_offset};
+use crate::{LocalEdit, EditBuilder, find_node_at_offset};
 
 pub fn join_lines(file: &File, range: TextRange) -> LocalEdit {
     let range = if range.is_empty() {
@@ -244,7 +244,7 @@ fn compute_ws(left: SyntaxNodeRef, right: SyntaxNodeRef) -> &'static str {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use test_utils::{check_action, extract_range, extract_offset, add_cursor};
+    use crate::test_utils::{check_action, extract_range, extract_offset, add_cursor};
 
     fn check_join_lines(before: &str, after: &str) {
         check_action(before, after, |file, offset| {