6 files changed, 171 insertions, 55 deletions

diff --git a/crates/ra_syntax/src/algo.rs b/crates/ra_syntax/src/algo.rs
index 21fca99a6..b87c7084e 100644
--- a/crates/ra_syntax/src/algo.rs
+++ b/crates/ra_syntax/src/algo.rs
@@ -4,10 +4,11 @@ use std::ops::RangeInclusive;
 
 use itertools::Itertools;
 use ra_text_edit::TextEditBuilder;
-use rustc_hash::FxHashMap;
+use rustc_hash::{FxHashMap, FxHashSet};
 
 use crate::{
-    AstNode, Direction, NodeOrToken, SyntaxElement, SyntaxNode, SyntaxNodePtr, TextRange, TextUnit,
+    AstNode, Direction, NodeOrToken, SyntaxElement, SyntaxNode, SyntaxNodePtr, SyntaxToken,
+    TextRange, TextUnit,
 };
 
 /// Returns ancestors of the node at the offset, sorted by length. This should
@@ -37,6 +38,17 @@ pub fn find_node_at_offset<N: AstNode>(syntax: &SyntaxNode, offset: TextUnit) ->
     ancestors_at_offset(syntax, offset).find_map(N::cast)
 }
 
+/// Skip to next non `trivia` token
+pub fn skip_trivia_token(mut token: SyntaxToken, direction: Direction) -> Option<SyntaxToken> {
+    while token.kind().is_trivia() {
+        token = match direction {
+            Direction::Next => token.next_token()?,
+            Direction::Prev => token.prev_token()?,
+        }
+    }
+    Some(token)
+}
+
 /// Finds the first sibling in the given direction which is not `trivia`
 pub fn non_trivia_sibling(element: SyntaxElement, direction: Direction) -> Option<SyntaxElement> {
     return match element {
@@ -56,6 +68,11 @@ pub fn find_covering_element(root: &SyntaxNode, range: TextRange) -> SyntaxEleme
     root.covering_element(range)
 }
 
+pub fn least_common_ancestor(u: &SyntaxNode, v: &SyntaxNode) -> Option<SyntaxNode> {
+    let u_ancestors = u.ancestors().collect::<FxHashSet<SyntaxNode>>();
+    v.ancestors().find(|it| u_ancestors.contains(it))
+}
+
 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub enum InsertPosition<T> {
     First,
@@ -127,6 +144,15 @@ pub fn diff(from: &SyntaxNode, to: &SyntaxNode) -> TreeDiff {
 pub fn insert_children(
     parent: &SyntaxNode,
     position: InsertPosition<SyntaxElement>,
+    to_insert: impl IntoIterator<Item = SyntaxElement>,
+) -> SyntaxNode {
+    let mut to_insert = to_insert.into_iter();
+    _insert_children(parent, position, &mut to_insert)
+}
+
+fn _insert_children(
+    parent: &SyntaxNode,
+    position: InsertPosition<SyntaxElement>,
     to_insert: &mut dyn Iterator<Item = SyntaxElement>,
 ) -> SyntaxNode {
     let mut delta = TextUnit::default();
@@ -161,6 +187,15 @@ pub fn insert_children(
 pub fn replace_children(
     parent: &SyntaxNode,
     to_delete: RangeInclusive<SyntaxElement>,
+    to_insert: impl IntoIterator<Item = SyntaxElement>,
+) -> SyntaxNode {
+    let mut to_insert = to_insert.into_iter();
+    _replace_children(parent, to_delete, &mut to_insert)
+}
+
+fn _replace_children(
+    parent: &SyntaxNode,
+    to_delete: RangeInclusive<SyntaxElement>,
     to_insert: &mut dyn Iterator<Item = SyntaxElement>,
 ) -> SyntaxNode {
     let start = position_of_child(parent, to_delete.start().clone());
@@ -185,14 +220,21 @@ pub fn replace_children(
 /// to create a type-safe abstraction on top of it instead.
 pub fn replace_descendants(
     parent: &SyntaxNode,
-    map: &impl Fn(&SyntaxElement) -> Option<SyntaxElement>,
+    map: impl Fn(&SyntaxElement) -> Option<SyntaxElement>,
+) -> SyntaxNode {
+    _replace_descendants(parent, &map)
+}
+
+fn _replace_descendants(
+    parent: &SyntaxNode,
+    map: &dyn Fn(&SyntaxElement) -> Option<SyntaxElement>,
 ) -> SyntaxNode {
     //  FIXME: this could be made much faster.
     let new_children = parent.children_with_tokens().map(|it| go(map, it)).collect::<Vec<_>>();
     return with_children(parent, new_children);
 
     fn go(
-        map: &impl Fn(&SyntaxElement) -> Option<SyntaxElement>,
+        map: &dyn Fn(&SyntaxElement) -> Option<SyntaxElement>,
         element: SyntaxElement,
     ) -> NodeOrToken<rowan::GreenNode, rowan::GreenToken> {
         if let Some(replacement) = map(&element) {
@@ -204,7 +246,7 @@ pub fn replace_descendants(
         match element {
             NodeOrToken::Token(it) => NodeOrToken::Token(it.green().clone()),
             NodeOrToken::Node(it) => {
-                NodeOrToken::Node(replace_descendants(&it, map).green().clone())
+                NodeOrToken::Node(_replace_descendants(&it, map).green().clone())
             }
         }
     }
diff --git a/crates/ra_syntax/src/ast/edit.rs b/crates/ra_syntax/src/ast/edit.rs
index 0e78d8b63..d2630e9e9 100644
--- a/crates/ra_syntax/src/ast/edit.rs
+++ b/crates/ra_syntax/src/ast/edit.rs
@@ -276,7 +276,7 @@ pub fn replace_descendants<N: AstNode, D: AstNode>(
         .into_iter()
         .map(|(from, to)| (from.syntax().clone().into(), to.syntax().clone().into()))
         .collect::<FxHashMap<SyntaxElement, _>>();
-    let new_syntax = algo::replace_descendants(parent.syntax(), &|n| map.get(n).cloned());
+    let new_syntax = algo::replace_descendants(parent.syntax(), |n| map.get(n).cloned());
     N::cast(new_syntax).unwrap()
 }
 
@@ -331,7 +331,7 @@ impl IndentLevel {
                 )
             })
             .collect();
-        algo::replace_descendants(&node, &|n| replacements.get(n).cloned())
+        algo::replace_descendants(&node, |n| replacements.get(n).cloned())
     }
 
     pub fn decrease_indent<N: AstNode>(self, node: N) -> N {
@@ -359,7 +359,7 @@ impl IndentLevel {
                 )
             })
             .collect();
-        algo::replace_descendants(&node, &|n| replacements.get(n).cloned())
+        algo::replace_descendants(&node, |n| replacements.get(n).cloned())
     }
 }
 
@@ -389,7 +389,7 @@ fn insert_children<N: AstNode>(
     position: InsertPosition<SyntaxElement>,
     to_insert: impl IntoIterator<Item = SyntaxElement>,
 ) -> N {
-    let new_syntax = algo::insert_children(parent.syntax(), position, &mut to_insert.into_iter());
+    let new_syntax = algo::insert_children(parent.syntax(), position, to_insert);
     N::cast(new_syntax).unwrap()
 }
 
@@ -404,8 +404,7 @@ fn replace_children<N: AstNode>(
     to_replace: RangeInclusive<SyntaxElement>,
     to_insert: impl IntoIterator<Item = SyntaxElement>,
 ) -> N {
-    let new_syntax =
-        algo::replace_children(parent.syntax(), to_replace, &mut to_insert.into_iter());
+    let new_syntax = algo::replace_children(parent.syntax(), to_replace, to_insert);
     N::cast(new_syntax).unwrap()
 }
 
diff --git a/crates/ra_syntax/src/ast/make.rs b/crates/ra_syntax/src/ast/make.rs
index 7c20fcc10..3f11b747f 100644
--- a/crates/ra_syntax/src/ast/make.rs
+++ b/crates/ra_syntax/src/ast/make.rs
@@ -12,11 +12,14 @@ pub fn name_ref(text: &str) -> ast::NameRef {
     ast_from_text(&format!("fn f() {{ {}; }}", text))
 }
 
-pub fn path_from_name_ref(name_ref: ast::NameRef) -> ast::Path {
-    path_from_text(&name_ref.syntax().to_string())
+pub fn path_segment(name_ref: ast::NameRef) -> ast::PathSegment {
+    ast_from_text(&format!("use {};", name_ref.syntax()))
 }
-pub fn path_qualified(qual: ast::Path, name_ref: ast::NameRef) -> ast::Path {
-    path_from_text(&format!("{}::{}", qual.syntax(), name_ref.syntax()))
+pub fn path_unqualified(segment: ast::PathSegment) -> ast::Path {
+    path_from_text(&format!("use {}", segment.syntax()))
+}
+pub fn path_qualified(qual: ast::Path, segment: ast::PathSegment) -> ast::Path {
+    path_from_text(&format!("{}::{}", qual.syntax(), segment.syntax()))
 }
 fn path_from_text(text: &str) -> ast::Path {
     ast_from_text(text)
diff --git a/crates/ra_syntax/src/ast/tokens.rs b/crates/ra_syntax/src/ast/tokens.rs
index ed8661faf..1a51b8d3b 100644
--- a/crates/ra_syntax/src/ast/tokens.rs
+++ b/crates/ra_syntax/src/ast/tokens.rs
@@ -110,6 +110,64 @@ impl Whitespace {
     }
 }
 
+pub struct QuoteOffsets {
+    pub quotes: [TextRange; 2],
+    pub contents: TextRange,
+}
+
+impl QuoteOffsets {
+    fn new(literal: &str) -> Option<QuoteOffsets> {
+        let left_quote = literal.find('"')?;
+        let right_quote = literal.rfind('"')?;
+        if left_quote == right_quote {
+            // `literal` only contains one quote
+            return None;
+        }
+
+        let start = TextUnit::from(0);
+        let left_quote = TextUnit::from_usize(left_quote) + TextUnit::of_char('"');
+        let right_quote = TextUnit::from_usize(right_quote);
+        let end = TextUnit::of_str(literal);
+
+        let res = QuoteOffsets {
+            quotes: [TextRange::from_to(start, left_quote), TextRange::from_to(right_quote, end)],
+            contents: TextRange::from_to(left_quote, right_quote),
+        };
+        Some(res)
+    }
+}
+
+pub trait HasQuotes: AstToken {
+    fn quote_offsets(&self) -> Option<QuoteOffsets> {
+        let text = self.text().as_str();
+        let offsets = QuoteOffsets::new(text)?;
+        let o = self.syntax().text_range().start();
+        let offsets = QuoteOffsets {
+            quotes: [offsets.quotes[0] + o, offsets.quotes[1] + o],
+            contents: offsets.contents + o,
+        };
+        Some(offsets)
+    }
+    fn open_quote_text_range(&self) -> Option<TextRange> {
+        self.quote_offsets().map(|it| it.quotes[0])
+    }
+
+    fn close_quote_text_range(&self) -> Option<TextRange> {
+        self.quote_offsets().map(|it| it.quotes[1])
+    }
+
+    fn text_range_between_quotes(&self) -> Option<TextRange> {
+        self.quote_offsets().map(|it| it.contents)
+    }
+}
+
+impl HasQuotes for String {}
+impl HasQuotes for RawString {}
+
+pub trait HasStringValue: HasQuotes {
+    fn value(&self) -> Option<std::string::String>;
+}
+
 pub struct String(SyntaxToken);
 
 impl AstToken for String {
@@ -124,21 +182,16 @@ impl AstToken for String {
     }
 }
 
-impl String {
-    pub fn value(&self) -> Option<std::string::String> {
+impl HasStringValue for String {
+    fn value(&self) -> Option<std::string::String> {
         let text = self.text().as_str();
-        let usual_string_range = find_usual_string_range(text)?;
-        let start_of_inside = usual_string_range.start().to_usize() + 1;
-        let end_of_inside = usual_string_range.end().to_usize();
-        let inside_str = &text[start_of_inside..end_of_inside];
+        let text = &text[self.text_range_between_quotes()? - self.syntax().text_range().start()];
 
-        let mut buf = std::string::String::with_capacity(inside_str.len());
+        let mut buf = std::string::String::with_capacity(text.len());
         let mut has_error = false;
-        rustc_lexer::unescape::unescape_str(inside_str, &mut |_, unescaped_char| {
-            match unescaped_char {
-                Ok(c) => buf.push(c),
-                Err(_) => has_error = true,
-            }
+        rustc_lexer::unescape::unescape_str(text, &mut |_, unescaped_char| match unescaped_char {
+            Ok(c) => buf.push(c),
+            Err(_) => has_error = true,
         });
 
         if has_error {
@@ -162,27 +215,18 @@ impl AstToken for RawString {
     }
 }
 
-impl RawString {
-    pub fn value(&self) -> Option<std::string::String> {
+impl HasStringValue for RawString {
+    fn value(&self) -> Option<std::string::String> {
         let text = self.text().as_str();
-        let usual_string_range = find_usual_string_range(text)?;
-        let start_of_inside = usual_string_range.start().to_usize() + 1;
-        let end_of_inside = usual_string_range.end().to_usize();
-        let inside_str = &text[start_of_inside..end_of_inside];
-        Some(inside_str.to_string())
-    }
-}
-
-fn find_usual_string_range(s: &str) -> Option<TextRange> {
-    let left_quote = s.find('"')?;
-    let right_quote = s.rfind('"')?;
-    if left_quote == right_quote {
-        // `s` only contains one quote
-        None
-    } else {
-        Some(TextRange::from_to(
-            TextUnit::from(left_quote as u32),
-            TextUnit::from(right_quote as u32),
-        ))
+        let text = &text[self.text_range_between_quotes()? - self.syntax().text_range().start()];
+        Some(text.to_string())
+    }
+}
+
+impl RawString {
+    pub fn map_range_up(&self, range: TextRange) -> Option<TextRange> {
+        let contents_range = self.text_range_between_quotes()?;
+        assert!(range.is_subrange(&TextRange::offset_len(0.into(), contents_range.len())));
+        Some(range + contents_range.start())
     }
 }
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0130_let_stmt.rs b/crates/ra_syntax/test_data/parser/inline/ok/0130_let_stmt.rs
index 86803fe08..fa8ee49a2 100644
--- a/crates/ra_syntax/test_data/parser/inline/ok/0130_let_stmt.rs
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0130_let_stmt.rs
@@ -5,4 +5,5 @@ fn foo() {
     let d: i32 = 92;
     let e: !;
     let _: ! = {};
+    let f = #[attr]||{};
 }
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0130_let_stmt.txt b/crates/ra_syntax/test_data/parser/inline/ok/0130_let_stmt.txt
index 97166cfd5..17739dfbd 100644
--- a/crates/ra_syntax/test_data/parser/inline/ok/0130_let_stmt.txt
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0130_let_stmt.txt
@@ -1,5 +1,5 @@
-SOURCE_FILE@[0; 110)
-  FN_DEF@[0; 109)
+SOURCE_FILE@[0; 135)
+  FN_DEF@[0; 134)
     FN_KW@[0; 2) "fn"
     WHITESPACE@[2; 3) " "
     NAME@[3; 6)
@@ -8,8 +8,8 @@ SOURCE_FILE@[0; 110)
       L_PAREN@[6; 7) "("
       R_PAREN@[7; 8) ")"
     WHITESPACE@[8; 9) " "
-    BLOCK_EXPR@[9; 109)
-      BLOCK@[9; 109)
+    BLOCK_EXPR@[9; 134)
+      BLOCK@[9; 134)
         L_CURLY@[9; 10) "{"
         WHITESPACE@[10; 15) "\n    "
         LET_STMT@[15; 21)
@@ -97,6 +97,33 @@ SOURCE_FILE@[0; 110)
               L_CURLY@[104; 105) "{"
               R_CURLY@[105; 106) "}"
           SEMI@[106; 107) ";"
-        WHITESPACE@[107; 108) "\n"
-        R_CURLY@[108; 109) "}"
-  WHITESPACE@[109; 110) "\n"
+        WHITESPACE@[107; 112) "\n    "
+        LET_STMT@[112; 132)
+          LET_KW@[112; 115) "let"
+          WHITESPACE@[115; 116) " "
+          BIND_PAT@[116; 117)
+            NAME@[116; 117)
+              IDENT@[116; 117) "f"
+          WHITESPACE@[117; 118) " "
+          EQ@[118; 119) "="
+          WHITESPACE@[119; 120) " "
+          LAMBDA_EXPR@[120; 131)
+            ATTR@[120; 127)
+              POUND@[120; 121) "#"
+              L_BRACK@[121; 122) "["
+              PATH@[122; 126)
+                PATH_SEGMENT@[122; 126)
+                  NAME_REF@[122; 126)
+                    IDENT@[122; 126) "attr"
+              R_BRACK@[126; 127) "]"
+            PARAM_LIST@[127; 129)
+              PIPE@[127; 128) "|"
+              PIPE@[128; 129) "|"
+            BLOCK_EXPR@[129; 131)
+              BLOCK@[129; 131)
+                L_CURLY@[129; 130) "{"
+                R_CURLY@[130; 131) "}"
+          SEMI@[131; 132) ";"
+        WHITESPACE@[132; 133) "\n"
+        R_CURLY@[133; 134) "}"
+  WHITESPACE@[134; 135) "\n"