1 files changed, 31 insertions, 8 deletions

diff --git a/crates/ra_editor/src/assists.rs b/crates/ra_editor/src/assists.rs
index 57b78342a..f839f6a7a 100644
--- a/crates/ra_editor/src/assists.rs
+++ b/crates/ra_editor/src/assists.rs
@@ -9,12 +9,15 @@ mod add_impl;
 mod introduce_variable;
 mod change_visibility;
 mod split_import;
+mod replace_if_let_with_match;
 
 use ra_text_edit::{TextEdit, TextEditBuilder};
 use ra_syntax::{
-    Direction, SyntaxNodeRef, TextUnit, TextRange,SourceFileNode, AstNode,
+    Direction, SyntaxNode, TextUnit, TextRange, SourceFile, AstNode,
     algo::{find_leaf_at_offset, find_covering_node, LeafAtOffset},
+    ast::{self, AstToken},
 };
+use itertools::Itertools;
 
 use crate::find_node_at_offset;
 
@@ -25,10 +28,11 @@ pub use self::{
     introduce_variable::introduce_variable,
     change_visibility::change_visibility,
     split_import::split_import,
+    replace_if_let_with_match::replace_if_let_with_match,
 };
 
 /// Return all the assists applicable at the given position.
-pub fn assists(file: &SourceFileNode, range: TextRange) -> Vec<LocalEdit> {
+pub fn assists(file: &SourceFile, range: TextRange) -> Vec<LocalEdit> {
     let ctx = AssistCtx::new(file, range);
     [
         flip_comma,
@@ -37,6 +41,7 @@ pub fn assists(file: &SourceFileNode, range: TextRange) -> Vec<LocalEdit> {
         introduce_variable,
         change_visibility,
         split_import,
+        replace_if_let_with_match,
     ]
     .iter()
     .filter_map(|&assist| ctx.clone().apply(assist))
@@ -50,7 +55,7 @@ pub struct LocalEdit {
     pub cursor_position: Option<TextUnit>,
 }
 
-fn non_trivia_sibling(node: SyntaxNodeRef, direction: Direction) -> Option<SyntaxNodeRef> {
+fn non_trivia_sibling(node: &SyntaxNode, direction: Direction) -> Option<&SyntaxNode> {
     node.siblings(direction)
         .skip(1)
         .find(|node| !node.kind().is_trivia())
@@ -88,7 +93,7 @@ fn non_trivia_sibling(node: SyntaxNodeRef, direction: Direction) -> Option<Synta
 /// easier to just compute the edit eagarly :-)
 #[derive(Debug, Clone)]
 pub struct AssistCtx<'a> {
-    source_file: &'a SourceFileNode,
+    source_file: &'a SourceFile,
     range: TextRange,
     should_compute_edit: bool,
 }
@@ -106,7 +111,7 @@ struct AssistBuilder {
 }
 
 impl<'a> AssistCtx<'a> {
-    pub fn new(source_file: &'a SourceFileNode, range: TextRange) -> AssistCtx {
+    pub fn new(source_file: &'a SourceFile, range: TextRange) -> AssistCtx {
         AssistCtx {
             source_file,
             range,
@@ -145,13 +150,13 @@ impl<'a> AssistCtx<'a> {
         }))
     }
 
-    pub(crate) fn leaf_at_offset(&self) -> LeafAtOffset<SyntaxNodeRef<'a>> {
+    pub(crate) fn leaf_at_offset(&self) -> LeafAtOffset<&'a SyntaxNode> {
         find_leaf_at_offset(self.source_file.syntax(), self.range.start())
     }
-    pub(crate) fn node_at_offset<N: AstNode<'a>>(&self) -> Option<N> {
+    pub(crate) fn node_at_offset<N: AstNode>(&self) -> Option<&'a N> {
         find_node_at_offset(self.source_file.syntax(), self.range.start())
     }
-    pub(crate) fn covering_node(&self) -> SyntaxNodeRef<'a> {
+    pub(crate) fn covering_node(&self) -> &'a SyntaxNode {
         find_covering_node(self.source_file.syntax(), self.range)
     }
 }
@@ -160,6 +165,13 @@ impl AssistBuilder {
     fn replace(&mut self, range: TextRange, replace_with: impl Into<String>) {
         self.edit.replace(range, replace_with.into())
     }
+    fn replace_node_and_indent(&mut self, node: &SyntaxNode, replace_with: impl Into<String>) {
+        let mut replace_with = replace_with.into();
+        if let Some(indent) = calc_indent(node) {
+            replace_with = reindent(&replace_with, indent)
+        }
+        self.replace(node.range(), replace_with)
+    }
     #[allow(unused)]
     fn delete(&mut self, range: TextRange) {
         self.edit.delete(range)
@@ -172,6 +184,17 @@ impl AssistBuilder {
     }
 }
 
+fn calc_indent(node: &SyntaxNode) -> Option<&str> {
+    let prev = node.prev_sibling()?;
+    let ws_text = ast::Whitespace::cast(prev)?.text();
+    ws_text.rfind('\n').map(|pos| &ws_text[pos + 1..])
+}
+
+fn reindent(text: &str, indent: &str) -> String {
+    let indent = format!("\n{}", indent);
+    text.lines().intersperse(&indent).collect()
+}
+
 #[cfg(test)]
 fn check_assist(assist: fn(AssistCtx) -> Option<Assist>, before: &str, after: &str) {
     crate::test_utils::check_action(before, after, |file, off| {