16 files changed, 532 insertions, 174 deletions

diff --git a/crates/assists/src/handlers/inline_function.rs b/crates/assists/src/handlers/inline_function.rs
new file mode 100644
index 000000000..2edf252b7
--- /dev/null
+++ b/crates/assists/src/handlers/inline_function.rs
@@ -0,0 +1,202 @@
+use ast::make;
+use hir::{HasSource, PathResolution};
+use syntax::{
+    ast::{self, edit::AstNodeEdit, ArgListOwner},
+    AstNode,
+};
+use test_utils::mark;
+
+use crate::{
+    assist_context::{AssistContext, Assists},
+    AssistId, AssistKind,
+};
+
+// Assist: inline_function
+//
+// Inlines a function body.
+//
+// ```
+// fn add(a: u32, b: u32) -> u32 { a + b }
+// fn main() {
+//     let x = add<|>(1, 2);
+// }
+// ```
+// ->
+// ```
+// fn add(a: u32, b: u32) -> u32 { a + b }
+// fn main() {
+//     let x = {
+//         let a = 1;
+//         let b = 2;
+//         a + b
+//     };
+// }
+// ```
+pub(crate) fn inline_function(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let path_expr: ast::PathExpr = ctx.find_node_at_offset()?;
+    let call = path_expr.syntax().parent().and_then(ast::CallExpr::cast)?;
+    let path = path_expr.path()?;
+
+    let function = match ctx.sema.resolve_path(&path)? {
+        PathResolution::Def(hir::ModuleDef::Function(f)) => f,
+        _ => return None,
+    };
+
+    let function_source = function.source(ctx.db())?;
+    let arguments: Vec<_> = call.arg_list()?.args().collect();
+    let parameters = function_parameter_patterns(&function_source.value)?;
+
+    if arguments.len() != parameters.len() {
+        // Can't inline the function because they've passed the wrong number of
+        // arguments to this function
+        mark::hit!(inline_function_incorrect_number_of_arguments);
+        return None;
+    }
+
+    let new_bindings = parameters.into_iter().zip(arguments);
+
+    let body = function_source.value.body()?;
+
+    acc.add(
+        AssistId("inline_function", AssistKind::RefactorInline),
+        format!("Inline `{}`", path),
+        call.syntax().text_range(),
+        |builder| {
+            let mut statements: Vec<ast::Stmt> = Vec::new();
+
+            for (pattern, value) in new_bindings {
+                statements.push(make::let_stmt(pattern, Some(value)).into());
+            }
+
+            statements.extend(body.statements());
+
+            let original_indentation = call.indent_level();
+            let replacement = make::block_expr(statements, body.expr())
+                .reset_indent()
+                .indent(original_indentation);
+
+            builder.replace_ast(ast::Expr::CallExpr(call), ast::Expr::BlockExpr(replacement));
+        },
+    )
+}
+
+fn function_parameter_patterns(value: &ast::Fn) -> Option<Vec<ast::Pat>> {
+    let mut patterns = Vec::new();
+
+    for param in value.param_list()?.params() {
+        let pattern = param.pat()?;
+        patterns.push(pattern);
+    }
+
+    Some(patterns)
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn no_args_or_return_value_gets_inlined_without_block() {
+        check_assist(
+            inline_function,
+            r#"
+fn foo() { println!("Hello, World!"); }
+fn main() {
+    fo<|>o();
+}
+"#,
+            r#"
+fn foo() { println!("Hello, World!"); }
+fn main() {
+    {
+        println!("Hello, World!");
+    };
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn args_with_side_effects() {
+        check_assist(
+            inline_function,
+            r#"
+fn foo(name: String) { println!("Hello, {}!", name); }
+fn main() {
+    foo<|>(String::from("Michael"));
+}
+"#,
+            r#"
+fn foo(name: String) { println!("Hello, {}!", name); }
+fn main() {
+    {
+        let name = String::from("Michael");
+        println!("Hello, {}!", name);
+    };
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn method_inlining_isnt_supported() {
+        check_assist_not_applicable(
+            inline_function,
+            r"
+struct Foo;
+impl Foo { fn bar(&self) {} }
+
+fn main() { Foo.bar<|>(); }
+",
+        );
+    }
+
+    #[test]
+    fn not_applicable_when_incorrect_number_of_parameters_are_provided() {
+        mark::check!(inline_function_incorrect_number_of_arguments);
+        check_assist_not_applicable(
+            inline_function,
+            r#"
+fn add(a: u32, b: u32) -> u32 { a + b }
+fn main() { let x = add<|>(42); }
+"#,
+        );
+    }
+
+    #[test]
+    fn function_with_multiple_statements() {
+        check_assist(
+            inline_function,
+            r#"
+fn foo(a: u32, b: u32) -> u32 {
+    let x = a + b;
+    let y = x - b;
+    x * y
+}
+
+fn main() {
+    let x = foo<|>(1, 2);
+}
+"#,
+            r#"
+fn foo(a: u32, b: u32) -> u32 {
+    let x = a + b;
+    let y = x - b;
+    x * y
+}
+
+fn main() {
+    let x = {
+        let a = 1;
+        let b = 2;
+        let x = a + b;
+        let y = x - b;
+        x * y
+    };
+}
+"#,
+        );
+    }
+}
diff --git a/crates/assists/src/lib.rs b/crates/assists/src/lib.rs
index 01baa65fe..9c2a95735 100644
--- a/crates/assists/src/lib.rs
+++ b/crates/assists/src/lib.rs
@@ -131,6 +131,7 @@ mod handlers {
     mod generate_impl;
     mod generate_new;
     mod infer_function_return_type;
+    mod inline_function;
     mod inline_local_variable;
     mod introduce_named_lifetime;
     mod invert_if;
@@ -183,6 +184,7 @@ mod handlers {
             generate_impl::generate_impl,
             generate_new::generate_new,
             infer_function_return_type::infer_function_return_type,
+            inline_function::inline_function,
             inline_local_variable::inline_local_variable,
             introduce_named_lifetime::introduce_named_lifetime,
             invert_if::invert_if,
diff --git a/crates/assists/src/tests/generated.rs b/crates/assists/src/tests/generated.rs
index 85e3c6742..b15352cf3 100644
--- a/crates/assists/src/tests/generated.rs
+++ b/crates/assists/src/tests/generated.rs
@@ -531,6 +531,29 @@ fn foo() -> i32 { 42i32 }
 }
 
 #[test]
+fn doctest_inline_function() {
+    check_doc_test(
+        "inline_function",
+        r#####"
+fn add(a: u32, b: u32) -> u32 { a + b }
+fn main() {
+    let x = add<|>(1, 2);
+}
+"#####,
+        r#####"
+fn add(a: u32, b: u32) -> u32 { a + b }
+fn main() {
+    let x = {
+        let a = 1;
+        let b = 2;
+        a + b
+    };
+}
+"#####,
+    )
+}
+
+#[test]
 fn doctest_inline_local_variable() {
     check_doc_test(
         "inline_local_variable",
diff --git a/crates/hir/src/code_model.rs b/crates/hir/src/code_model.rs
index 071e553a8..1a4aa78fb 100644
--- a/crates/hir/src/code_model.rs
+++ b/crates/hir/src/code_model.rs
@@ -743,6 +743,18 @@ impl Function {
         db.function_data(self.id).name.clone()
     }
 
+    /// Get this function's return type
+    pub fn ret_type(self, db: &dyn HirDatabase) -> Type {
+        let resolver = self.id.resolver(db.upcast());
+        let ret_type = &db.function_data(self.id).ret_type;
+        let ctx = hir_ty::TyLoweringContext::new(db, &resolver);
+        let environment = TraitEnvironment::lower(db, &resolver);
+        Type {
+            krate: self.id.lookup(db.upcast()).container.module(db.upcast()).krate,
+            ty: InEnvironment { value: Ty::from_hir_ext(&ctx, ret_type).0, environment },
+        }
+    }
+
     pub fn self_param(self, db: &dyn HirDatabase) -> Option<SelfParam> {
         if !db.function_data(self.id).has_self_param {
             return None;
diff --git a/crates/hir_def/src/attr.rs b/crates/hir_def/src/attr.rs
index 6b79e7bad..9e6426b31 100644
--- a/crates/hir_def/src/attr.rs
+++ b/crates/hir_def/src/attr.rs
@@ -2,6 +2,7 @@
 
 use std::{ops, sync::Arc};
 
+use arena::map::ArenaMap;
 use base_db::CrateId;
 use cfg::{CfgExpr, CfgOptions};
 use either::Either;
@@ -21,7 +22,8 @@ use crate::{
     nameres::ModuleSource,
     path::{ModPath, PathKind},
     src::HasChildSource,
-    AdtId, AttrDefId, GenericParamId, Lookup,
+    AdtId, AttrDefId, EnumId, GenericParamId, HasModule, LocalEnumVariantId, LocalFieldId, Lookup,
+    VariantId,
 };
 
 /// Holds documentation
@@ -210,16 +212,10 @@ impl Attrs {
                 }
             }
             AttrDefId::FieldId(it) => {
-                let src = it.parent.child_source(db);
-                match &src.value[it.local_id] {
-                    Either::Left(_tuple) => RawAttrs::default(),
-                    Either::Right(record) => RawAttrs::from_attrs_owner(db, src.with_value(record)),
-                }
+                return db.fields_attrs(it.parent)[it.local_id].clone();
             }
-            AttrDefId::EnumVariantId(var_id) => {
-                let src = var_id.parent.child_source(db);
-                let src = src.as_ref().map(|it| &it[var_id.local_id]);
-                RawAttrs::from_attrs_owner(db, src.map(|it| it as &dyn AttrsOwner))
+            AttrDefId::EnumVariantId(it) => {
+                return db.variants_attrs(it.parent)[it.local_id].clone();
             }
             AttrDefId::AdtId(it) => match it {
                 AdtId::StructId(it) => attrs_from_item_tree(it.lookup(db).id, db),
@@ -259,6 +255,46 @@ impl Attrs {
         raw_attrs.filter(db, def.krate(db))
     }
 
+    pub(crate) fn variants_attrs_query(
+        db: &dyn DefDatabase,
+        e: EnumId,
+    ) -> Arc<ArenaMap<LocalEnumVariantId, Attrs>> {
+        let krate = e.lookup(db).container.module(db).krate;
+        let src = e.child_source(db);
+        let mut res = ArenaMap::default();
+
+        for (id, var) in src.value.iter() {
+            let attrs = RawAttrs::from_attrs_owner(db, src.with_value(var as &dyn AttrsOwner))
+                .filter(db, krate);
+
+            res.insert(id, attrs)
+        }
+
+        Arc::new(res)
+    }
+
+    pub(crate) fn fields_attrs_query(
+        db: &dyn DefDatabase,
+        v: VariantId,
+    ) -> Arc<ArenaMap<LocalFieldId, Attrs>> {
+        let krate = v.module(db).krate;
+        let src = v.child_source(db);
+        let mut res = ArenaMap::default();
+
+        for (id, fld) in src.value.iter() {
+            let attrs = match fld {
+                Either::Left(_tuple) => Attrs::default(),
+                Either::Right(record) => {
+                    RawAttrs::from_attrs_owner(db, src.with_value(record)).filter(db, krate)
+                }
+            };
+
+            res.insert(id, attrs);
+        }
+
+        Arc::new(res)
+    }
+
     pub fn by_key(&self, key: &'static str) -> AttrQuery<'_> {
         AttrQuery { attrs: self, key }
     }
diff --git a/crates/hir_def/src/db.rs b/crates/hir_def/src/db.rs
index d1a459066..d3bf5b34c 100644
--- a/crates/hir_def/src/db.rs
+++ b/crates/hir_def/src/db.rs
@@ -1,6 +1,7 @@
 //! Defines database & queries for name resolution.
 use std::sync::Arc;
 
+use arena::map::ArenaMap;
 use base_db::{salsa, CrateId, SourceDatabase, Upcast};
 use hir_expand::{db::AstDatabase, HirFileId};
 use syntax::SmolStr;
@@ -16,8 +17,8 @@ use crate::{
     lang_item::{LangItemTarget, LangItems},
     nameres::CrateDefMap,
     AttrDefId, ConstId, ConstLoc, DefWithBodyId, EnumId, EnumLoc, FunctionId, FunctionLoc,
-    GenericDefId, ImplId, ImplLoc, StaticId, StaticLoc, StructId, StructLoc, TraitId, TraitLoc,
-    TypeAliasId, TypeAliasLoc, UnionId, UnionLoc,
+    GenericDefId, ImplId, ImplLoc, LocalEnumVariantId, LocalFieldId, StaticId, StaticLoc, StructId,
+    StructLoc, TraitId, TraitLoc, TypeAliasId, TypeAliasLoc, UnionId, UnionLoc, VariantId,
 };
 
 #[salsa::query_group(InternDatabaseStorage)]
@@ -92,6 +93,12 @@ pub trait DefDatabase: InternDatabase + AstDatabase + Upcast<dyn AstDatabase> {
     #[salsa::invoke(GenericParams::generic_params_query)]
     fn generic_params(&self, def: GenericDefId) -> Arc<GenericParams>;
 
+    #[salsa::invoke(Attrs::variants_attrs_query)]
+    fn variants_attrs(&self, def: EnumId) -> Arc<ArenaMap<LocalEnumVariantId, Attrs>>;
+
+    #[salsa::invoke(Attrs::fields_attrs_query)]
+    fn fields_attrs(&self, def: VariantId) -> Arc<ArenaMap<LocalFieldId, Attrs>>;
+
     #[salsa::invoke(Attrs::attrs_query)]
     fn attrs(&self, def: AttrDefId) -> Attrs;
 
diff --git a/crates/hir_expand/src/proc_macro.rs b/crates/hir_expand/src/proc_macro.rs
index 7c77f6ce0..1923daca5 100644
--- a/crates/hir_expand/src/proc_macro.rs
+++ b/crates/hir_expand/src/proc_macro.rs
@@ -58,7 +58,7 @@ impl ProcMacroExpander {
 }
 
 fn eat_punct(cursor: &mut Cursor, c: char) -> bool {
-    if let Some(tt::TokenTree::Leaf(tt::Leaf::Punct(punct))) = cursor.token_tree() {
+    if let Some(tt::buffer::TokenTreeRef::Leaf(tt::Leaf::Punct(punct), _)) = cursor.token_tree() {
         if punct.char == c {
             *cursor = cursor.bump();
             return true;
@@ -68,7 +68,7 @@ fn eat_punct(cursor: &mut Cursor, c: char) -> bool {
 }
 
 fn eat_subtree(cursor: &mut Cursor, kind: tt::DelimiterKind) -> bool {
-    if let Some(tt::TokenTree::Subtree(subtree)) = cursor.token_tree() {
+    if let Some(tt::buffer::TokenTreeRef::Subtree(subtree, _)) = cursor.token_tree() {
         if Some(kind) == subtree.delimiter_kind() {
             *cursor = cursor.bump_subtree();
             return true;
@@ -78,7 +78,7 @@ fn eat_subtree(cursor: &mut Cursor, kind: tt::DelimiterKind) -> bool {
 }
 
 fn eat_ident(cursor: &mut Cursor, t: &str) -> bool {
-    if let Some(tt::TokenTree::Leaf(tt::Leaf::Ident(ident))) = cursor.token_tree() {
+    if let Some(tt::buffer::TokenTreeRef::Leaf(tt::Leaf::Ident(ident), _)) = cursor.token_tree() {
         if t == ident.text.as_str() {
             *cursor = cursor.bump();
             return true;
@@ -88,7 +88,7 @@ fn eat_ident(cursor: &mut Cursor, t: &str) -> bool {
 }
 
 fn remove_derive_attrs(tt: &tt::Subtree) -> Option<tt::Subtree> {
-    let buffer = TokenBuffer::new(&tt.token_trees);
+    let buffer = TokenBuffer::from_tokens(&tt.token_trees);
     let mut p = buffer.begin();
     let mut result = tt::Subtree::default();
 
@@ -106,7 +106,7 @@ fn remove_derive_attrs(tt: &tt::Subtree) -> Option<tt::Subtree> {
             }
         }
 
-        result.token_trees.push(curr.token_tree()?.clone());
+        result.token_trees.push(curr.token_tree()?.cloned());
         p = curr.bump();
     }
 
diff --git a/crates/hir_ty/Cargo.toml b/crates/hir_ty/Cargo.toml
index 3d1778590..b0a453961 100644
--- a/crates/hir_ty/Cargo.toml
+++ b/crates/hir_ty/Cargo.toml
@@ -17,9 +17,9 @@ ena = "0.14.0"
 log = "0.4.8"
 rustc-hash = "1.1.0"
 scoped-tls = "1"
-chalk-solve = { version = "0.45", default-features = false }
-chalk-ir = "0.45"
-chalk-recursive = "0.45"
+chalk-solve = { version = "0.47", default-features = false }
+chalk-ir = "0.47"
+chalk-recursive = "0.47"
 
 stdx = { path = "../stdx", version = "0.0.0" }
 hir_def = { path = "../hir_def", version = "0.0.0" }
diff --git a/crates/mbe/src/mbe_expander/matcher.rs b/crates/mbe/src/mbe_expander/matcher.rs
index ab5f87c48..fdc8844ce 100644
--- a/crates/mbe/src/mbe_expander/matcher.rs
+++ b/crates/mbe/src/mbe_expander/matcher.rs
@@ -309,7 +309,7 @@ impl<'a> TtIter<'a> {
             }
         }
 
-        let buffer = TokenBuffer::new(&self.inner.as_slice());
+        let buffer = TokenBuffer::from_tokens(&self.inner.as_slice());
         let mut src = SubtreeTokenSource::new(&buffer);
         let mut sink = OffsetTokenSink { cursor: buffer.begin(), error: false };
 
@@ -336,11 +336,11 @@ impl<'a> TtIter<'a> {
             err = Some(err!("no tokens consumed"));
         }
         let res = match res.len() {
-            1 => Some(res[0].clone()),
+            1 => Some(res[0].cloned()),
             0 => None,
             _ => Some(tt::TokenTree::Subtree(tt::Subtree {
                 delimiter: None,
-                token_trees: res.into_iter().cloned().collect(),
+                token_trees: res.into_iter().map(|it| it.cloned()).collect(),
             })),
         };
         ExpandResult { value: res, err }
diff --git a/crates/mbe/src/subtree_source.rs b/crates/mbe/src/subtree_source.rs
index d10d4b70e..d7433bd35 100644
--- a/crates/mbe/src/subtree_source.rs
+++ b/crates/mbe/src/subtree_source.rs
@@ -1,129 +1,104 @@
 //! FIXME: write short doc here
 
 use parser::{Token, TokenSource};
-use std::cell::{Cell, Ref, RefCell};
 use syntax::{lex_single_syntax_kind, SmolStr, SyntaxKind, SyntaxKind::*, T};
-use tt::buffer::{Cursor, TokenBuffer};
+use tt::buffer::TokenBuffer;
 
 #[derive(Debug, Clone, Eq, PartialEq)]
 struct TtToken {
-    kind: SyntaxKind,
-    is_joint_to_next: bool,
+    tt: Token,
     text: SmolStr,
 }
 
-pub(crate) struct SubtreeTokenSource<'a> {
-    cached_cursor: Cell<Cursor<'a>>,
-    cached: RefCell<Vec<Option<TtToken>>>,
+pub(crate) struct SubtreeTokenSource {
+    cached: Vec<TtToken>,
     curr: (Token, usize),
 }
 
-impl<'a> SubtreeTokenSource<'a> {
+impl<'a> SubtreeTokenSource {
     // Helper function used in test
     #[cfg(test)]
     pub(crate) fn text(&self) -> SmolStr {
-        match *self.get(self.curr.1) {
+        match self.cached.get(self.curr.1) {
             Some(ref tt) => tt.text.clone(),
             _ => SmolStr::new(""),
         }
     }
 }
 
-impl<'a> SubtreeTokenSource<'a> {
-    pub(crate) fn new(buffer: &'a TokenBuffer) -> SubtreeTokenSource<'a> {
-        let cursor = buffer.begin();
+impl<'a> SubtreeTokenSource {
+    pub(crate) fn new(buffer: &TokenBuffer) -> SubtreeTokenSource {
+        let mut current = buffer.begin();
+        let mut cached = Vec::with_capacity(100);
 
-        let mut res = SubtreeTokenSource {
-            curr: (Token { kind: EOF, is_jointed_to_next: false }, 0),
-            cached_cursor: Cell::new(cursor),
-            cached: RefCell::new(Vec::with_capacity(10)),
-        };
-        res.curr = (res.mk_token(0), 0);
-        res
-    }
+        while !current.eof() {
+            let cursor = current;
+            let tt = cursor.token_tree();
 
-    fn mk_token(&self, pos: usize) -> Token {
-        match *self.get(pos) {
-            Some(ref tt) => Token { kind: tt.kind, is_jointed_to_next: tt.is_joint_to_next },
-            None => Token { kind: EOF, is_jointed_to_next: false },
-        }
-    }
-
-    fn get(&self, pos: usize) -> Ref<Option<TtToken>> {
-        fn is_lifetime(c: Cursor) -> Option<(Cursor, SmolStr)> {
-            let tkn = c.token_tree();
-
-            if let Some(tt::TokenTree::Leaf(tt::Leaf::Punct(punct))) = tkn {
+            // Check if it is lifetime
+            if let Some(tt::buffer::TokenTreeRef::Leaf(tt::Leaf::Punct(punct), _)) = tt {
                 if punct.char == '\'' {
-                    let next = c.bump();
-                    if let Some(tt::TokenTree::Leaf(tt::Leaf::Ident(ident))) = next.token_tree() {
-                        let res_cursor = next.bump();
-                        let text = SmolStr::new("'".to_string() + &ident.to_string());
-
-                        return Some((res_cursor, text));
+                    let next = cursor.bump();
+                    if let Some(tt::buffer::TokenTreeRef::Leaf(tt::Leaf::Ident(ident), _)) =
+                        next.token_tree()
+                    {
+                        let text = SmolStr::new("'".to_string() + &ident.text);
+                        cached.push(TtToken {
+                            tt: Token { kind: LIFETIME_IDENT, is_jointed_to_next: false },
+                            text,
+                        });
+                        current = next.bump();
+                        continue;
                     } else {
                         panic!("Next token must be ident : {:#?}", next.token_tree());
                     }
                 }
             }
 
-            None
-        }
-
-        if pos < self.cached.borrow().len() {
-            return Ref::map(self.cached.borrow(), |c| &c[pos]);
-        }
-
-        {
-            let mut cached = self.cached.borrow_mut();
-            while pos >= cached.len() {
-                let cursor = self.cached_cursor.get();
-                if cursor.eof() {
-                    cached.push(None);
-                    continue;
+            current = match tt {
+                Some(tt::buffer::TokenTreeRef::Leaf(leaf, _)) => {
+                    cached.push(convert_leaf(&leaf));
+                    cursor.bump()
                 }
-
-                if let Some((curr, text)) = is_lifetime(cursor) {
-                    cached.push(Some(TtToken {
-                        kind: LIFETIME_IDENT,
-                        is_joint_to_next: false,
-                        text,
-                    }));
-                    self.cached_cursor.set(curr);
-                    continue;
+                Some(tt::buffer::TokenTreeRef::Subtree(subtree, _)) => {
+                    cached.push(convert_delim(subtree.delimiter_kind(), false));
+                    cursor.subtree().unwrap()
                 }
-
-                match cursor.token_tree() {
-                    Some(tt::TokenTree::Leaf(leaf)) => {
-                        cached.push(Some(convert_leaf(&leaf)));
-                        self.cached_cursor.set(cursor.bump());
-                    }
-                    Some(tt::TokenTree::Subtree(subtree)) => {
-                        self.cached_cursor.set(cursor.subtree().unwrap());
-                        cached.push(Some(convert_delim(subtree.delimiter_kind(), false)));
-                    }
-                    None => {
-                        if let Some(subtree) = cursor.end() {
-                            cached.push(Some(convert_delim(subtree.delimiter_kind(), true)));
-                            self.cached_cursor.set(cursor.bump());
-                        }
+                None => {
+                    if let Some(subtree) = cursor.end() {
+                        cached.push(convert_delim(subtree.delimiter_kind(), true));
+                        cursor.bump()
+                    } else {
+                        continue;
                     }
                 }
-            }
+            };
         }
 
-        Ref::map(self.cached.borrow(), |c| &c[pos])
+        let mut res = SubtreeTokenSource {
+            curr: (Token { kind: EOF, is_jointed_to_next: false }, 0),
+            cached,
+        };
+        res.curr = (res.token(0), 0);
+        res
+    }
+
+    fn token(&self, pos: usize) -> Token {
+        match self.cached.get(pos) {
+            Some(it) => it.tt,
+            None => Token { kind: EOF, is_jointed_to_next: false },
+        }
     }
 }
 
-impl<'a> TokenSource for SubtreeTokenSource<'a> {
+impl<'a> TokenSource for SubtreeTokenSource {
     fn current(&self) -> Token {
         self.curr.0
     }
 
     /// Lookahead n token
     fn lookahead_nth(&self, n: usize) -> Token {
-        self.mk_token(self.curr.1 + n)
+        self.token(self.curr.1 + n)
     }
 
     /// bump cursor to next token
@@ -131,13 +106,12 @@ impl<'a> TokenSource for SubtreeTokenSource<'a> {
         if self.current().kind == EOF {
             return;
         }
-
-        self.curr = (self.mk_token(self.curr.1 + 1), self.curr.1 + 1);
+        self.curr = (self.token(self.curr.1 + 1), self.curr.1 + 1);
     }
 
     /// Is the current token a specified keyword?
     fn is_keyword(&self, kw: &str) -> bool {
-        match *self.get(self.curr.1) {
+        match self.cached.get(self.curr.1) {
             Some(ref t) => t.text == *kw,
             _ => false,
         }
@@ -155,7 +129,7 @@ fn convert_delim(d: Option<tt::DelimiterKind>, closing: bool) -> TtToken {
     let idx = closing as usize;
     let kind = kinds[idx];
     let text = if !texts.is_empty() { &texts[idx..texts.len() - (1 - idx)] } else { "" };
-    TtToken { kind, is_joint_to_next: false, text: SmolStr::new(text) }
+    TtToken { tt: Token { kind, is_jointed_to_next: false }, text: SmolStr::new(text) }
 }
 
 fn convert_literal(l: &tt::Literal) -> TtToken {
@@ -169,7 +143,7 @@ fn convert_literal(l: &tt::Literal) -> TtToken {
         })
         .unwrap_or_else(|| panic!("Fail to convert given literal {:#?}", &l));
 
-    TtToken { kind, is_joint_to_next: false, text: l.text.clone() }
+    TtToken { tt: Token { kind, is_jointed_to_next: false }, text: l.text.clone() }
 }
 
 fn convert_ident(ident: &tt::Ident) -> TtToken {
@@ -180,7 +154,7 @@ fn convert_ident(ident: &tt::Ident) -> TtToken {
         _ => SyntaxKind::from_keyword(ident.text.as_str()).unwrap_or(IDENT),
     };
 
-    TtToken { kind, is_joint_to_next: false, text: ident.text.clone() }
+    TtToken { tt: Token { kind, is_jointed_to_next: false }, text: ident.text.clone() }
 }
 
 fn convert_punct(p: tt::Punct) -> TtToken {
@@ -194,7 +168,7 @@ fn convert_punct(p: tt::Punct) -> TtToken {
         let s: &str = p.char.encode_utf8(&mut buf);
         SmolStr::new(s)
     };
-    TtToken { kind, is_joint_to_next: p.spacing == tt::Spacing::Joint, text }
+    TtToken { tt: Token { kind, is_jointed_to_next: p.spacing == tt::Spacing::Joint }, text }
 }
 
 fn convert_leaf(leaf: &tt::Leaf) -> TtToken {
@@ -208,6 +182,7 @@ fn convert_leaf(leaf: &tt::Leaf) -> TtToken {
 #[cfg(test)]
 mod tests {
     use super::{convert_literal, TtToken};
+    use parser::Token;
     use syntax::{SmolStr, SyntaxKind};
 
     #[test]
@@ -218,8 +193,7 @@ mod tests {
                 text: SmolStr::new("-42.0")
             }),
             TtToken {
-                kind: SyntaxKind::FLOAT_NUMBER,
-                is_joint_to_next: false,
+                tt: Token { kind: SyntaxKind::FLOAT_NUMBER, is_jointed_to_next: false },
                 text: SmolStr::new("-42.0")
             }
         );
diff --git a/crates/mbe/src/syntax_bridge.rs b/crates/mbe/src/syntax_bridge.rs
index 265c0d63d..671036e1c 100644
--- a/crates/mbe/src/syntax_bridge.rs
+++ b/crates/mbe/src/syntax_bridge.rs
@@ -70,15 +70,12 @@ pub fn token_tree_to_syntax_node(
     tt: &tt::Subtree,
     fragment_kind: FragmentKind,
 ) -> Result<(Parse<SyntaxNode>, TokenMap), ExpandError> {
-    let tmp;
-    let tokens = match tt {
-        tt::Subtree { delimiter: None, token_trees } => token_trees.as_slice(),
-        _ => {
-            tmp = [tt.clone().into()];
-            &tmp[..]
+    let buffer = match tt {
+        tt::Subtree { delimiter: None, token_trees } => {
+            TokenBuffer::from_tokens(token_trees.as_slice())
         }
+        _ => TokenBuffer::from_subtree(tt),
     };
-    let buffer = TokenBuffer::new(&tokens);
     let mut token_source = SubtreeTokenSource::new(&buffer);
     let mut tree_sink = TtTreeSink::new(buffer.begin());
     parser::parse_fragment(&mut token_source, &mut tree_sink, fragment_kind);
@@ -414,7 +411,7 @@ trait TokenConvertor {
     fn id_alloc(&mut self) -> &mut TokenIdAlloc;
 }
 
-impl<'a> SrcToken for (RawToken, &'a str) {
+impl<'a> SrcToken for (&'a RawToken, &'a str) {
     fn kind(&self) -> SyntaxKind {
         self.0.kind
     }
@@ -431,7 +428,7 @@ impl<'a> SrcToken for (RawToken, &'a str) {
 impl RawConvertor<'_> {}
 
 impl<'a> TokenConvertor for RawConvertor<'a> {
-    type Token = (RawToken, &'a str);
+    type Token = (&'a RawToken, &'a str);
 
     fn convert_doc_comment(&self, token: &Self::Token) -> Option<Vec<tt::TokenTree>> {
         convert_doc_comment(&doc_comment(token.1))
@@ -442,11 +439,11 @@ impl<'a> TokenConvertor for RawConvertor<'a> {
         let range = TextRange::at(self.offset, token.len);
         self.offset += token.len;
 
-        Some(((*token, &self.text[range]), range))
+        Some(((token, &self.text[range]), range))
     }
 
     fn peek(&self) -> Option<Self::Token> {
-        let token = self.inner.as_slice().get(0).cloned();
+        let token = self.inner.as_slice().get(0);
 
         token.map(|it| {
             let range = TextRange::at(self.offset, it.len);
@@ -601,17 +598,16 @@ impl<'a> TtTreeSink<'a> {
     }
 }
 
-fn delim_to_str(d: Option<tt::DelimiterKind>, closing: bool) -> SmolStr {
+fn delim_to_str(d: Option<tt::DelimiterKind>, closing: bool) -> &'static str {
     let texts = match d {
         Some(tt::DelimiterKind::Parenthesis) => "()",
         Some(tt::DelimiterKind::Brace) => "{}",
         Some(tt::DelimiterKind::Bracket) => "[]",
-        None => return "".into(),
+        None => return "",
     };
 
     let idx = closing as usize;
-    let text = &texts[idx..texts.len() - (1 - idx)];
-    text.into()
+    &texts[idx..texts.len() - (1 - idx)]
 }
 
 impl<'a> TreeSink for TtTreeSink<'a> {
@@ -626,29 +622,32 @@ impl<'a> TreeSink for TtTreeSink<'a> {
 
         let mut last = self.cursor;
         for _ in 0..n_tokens {
+            let tmp_str: SmolStr;
             if self.cursor.eof() {
                 break;
             }
             last = self.cursor;
-            let text: SmolStr = match self.cursor.token_tree() {
-                Some(tt::TokenTree::Leaf(leaf)) => {
+            let text: &str = match self.cursor.token_tree() {
+                Some(tt::buffer::TokenTreeRef::Leaf(leaf, _)) => {
                     // Mark the range if needed
                     let (text, id) = match leaf {
-                        tt::Leaf::Ident(ident) => (ident.text.clone(), ident.id),
+                        tt::Leaf::Ident(ident) => (&ident.text, ident.id),
                         tt::Leaf::Punct(punct) => {
                             assert!(punct.char.is_ascii());
                             let char = &(punct.char as u8);
-                            let text = std::str::from_utf8(std::slice::from_ref(char)).unwrap();
-                            (SmolStr::new_inline(text), punct.id)
+                            tmp_str = SmolStr::new_inline(
+                                std::str::from_utf8(std::slice::from_ref(char)).unwrap(),
+                            );
+                            (&tmp_str, punct.id)
                         }
-                        tt::Leaf::Literal(lit) => (lit.text.clone(), lit.id),
+                        tt::Leaf::Literal(lit) => (&lit.text, lit.id),
                     };
                     let range = TextRange::at(self.text_pos, TextSize::of(text.as_str()));
                     self.token_map.insert(id, range);
                     self.cursor = self.cursor.bump();
                     text
                 }
-                Some(tt::TokenTree::Subtree(subtree)) => {
+                Some(tt::buffer::TokenTreeRef::Subtree(subtree, _)) => {
                     self.cursor = self.cursor.subtree().unwrap();
                     if let Some(id) = subtree.delimiter.map(|it| it.id) {
                         self.open_delims.insert(id, self.text_pos);
@@ -672,7 +671,7 @@ impl<'a> TreeSink for TtTreeSink<'a> {
                 }
             };
             self.buf += &text;
-            self.text_pos += TextSize::of(text.as_str());
+            self.text_pos += TextSize::of(text);
         }
 
         let text = SmolStr::new(self.buf.as_str());
@@ -682,8 +681,8 @@ impl<'a> TreeSink for TtTreeSink<'a> {
         // Add whitespace between adjoint puncts
         let next = last.bump();
         if let (
-            Some(tt::TokenTree::Leaf(tt::Leaf::Punct(curr))),
-            Some(tt::TokenTree::Leaf(tt::Leaf::Punct(_))),
+            Some(tt::buffer::TokenTreeRef::Leaf(tt::Leaf::Punct(curr), _)),
+            Some(tt::buffer::TokenTreeRef::Leaf(tt::Leaf::Punct(_), _)),
         ) = (last.token_tree(), next.token_tree())
         {
             // Note: We always assume the semi-colon would be the last token in
@@ -742,7 +741,7 @@ mod tests {
         )
         .expand_tt("literals!(foo);");
         let tts = &[expansion.into()];
-        let buffer = tt::buffer::TokenBuffer::new(tts);
+        let buffer = tt::buffer::TokenBuffer::from_tokens(tts);
         let mut tt_src = SubtreeTokenSource::new(&buffer);
         let mut tokens = vec![];
         while tt_src.current().kind != EOF {
diff --git a/crates/rust-analyzer/src/config.rs b/crates/rust-analyzer/src/config.rs
index 685a9fdf0..a5b1d90b1 100644
--- a/crates/rust-analyzer/src/config.rs
+++ b/crates/rust-analyzer/src/config.rs
@@ -777,9 +777,8 @@ fn manual(fields: &[(&'static str, &'static str, &[&str], &str)]) -> String {
     fields
         .iter()
         .map(|(field, _ty, doc, default)| {
-            let name = field.replace("_", ".");
-            let name = format!("rust-analyzer.{} (default: `{}`)", name, default);
-            format!("{}::\n{}\n", name, doc.join(" "))
+            let name = format!("rust-analyzer.{}", field.replace("_", "."));
+            format!("[[{}]]{} (default: `{}`)::\n{}\n", name, name, default, doc.join(" "))
         })
         .collect::<String>()
 }
diff --git a/crates/ssr/src/parsing.rs b/crates/ssr/src/parsing.rs
index 289affe90..3d5e4feb7 100644
--- a/crates/ssr/src/parsing.rs
+++ b/crates/ssr/src/parsing.rs
@@ -73,12 +73,18 @@ impl ParsedRule {
             placeholders_by_stand_in: pattern.placeholders_by_stand_in(),
             rules: Vec::new(),
         };
-        builder.try_add(ast::Expr::parse(&raw_pattern), raw_template.map(ast::Expr::parse));
+
+        let raw_template_stmt = raw_template.map(ast::Stmt::parse);
+        if let raw_template_expr @ Some(Ok(_)) = raw_template.map(ast::Expr::parse) {
+            builder.try_add(ast::Expr::parse(&raw_pattern), raw_template_expr);
+        } else {
+            builder.try_add(ast::Expr::parse(&raw_pattern), raw_template_stmt.clone());
+        }
         builder.try_add(ast::Type::parse(&raw_pattern), raw_template.map(ast::Type::parse));
         builder.try_add(ast::Item::parse(&raw_pattern), raw_template.map(ast::Item::parse));
         builder.try_add(ast::Path::parse(&raw_pattern), raw_template.map(ast::Path::parse));
         builder.try_add(ast::Pat::parse(&raw_pattern), raw_template.map(ast::Pat::parse));
-        builder.try_add(ast::Stmt::parse(&raw_pattern), raw_template.map(ast::Stmt::parse));
+        builder.try_add(ast::Stmt::parse(&raw_pattern), raw_template_stmt);
         builder.build()
     }
 }
@@ -89,7 +95,11 @@ struct RuleBuilder {
 }
 
 impl RuleBuilder {
-    fn try_add<T: AstNode>(&mut self, pattern: Result<T, ()>, template: Option<Result<T, ()>>) {
+    fn try_add<T: AstNode, T2: AstNode>(
+        &mut self,
+        pattern: Result<T, ()>,
+        template: Option<Result<T2, ()>>,
+    ) {
         match (pattern, template) {
             (Ok(pattern), Some(Ok(template))) => self.rules.push(ParsedRule {
                 placeholders_by_stand_in: self.placeholders_by_stand_in.clone(),
diff --git a/crates/ssr/src/tests.rs b/crates/ssr/src/tests.rs
index c4149a849..db9cb8ca1 100644
--- a/crates/ssr/src/tests.rs
+++ b/crates/ssr/src/tests.rs
@@ -204,6 +204,53 @@ fn ssr_let_stmt_replace_expr() {
 }
 
 #[test]
+fn ssr_blockexpr_replace_stmt_with_stmt() {
+    assert_ssr_transform(
+        "if $a() {$b;} ==>> $b;",
+        "{
+    if foo() {
+        bar();
+    }
+    Ok(())
+}",
+        expect![[r#"{
+    bar();
+    Ok(())
+}"#]],
+    );
+}
+
+#[test]
+fn ssr_blockexpr_match_trailing_expr() {
+    assert_matches(
+        "if $a() {$b;}",
+        "{
+    if foo() {
+        bar();
+    }
+}",
+        &["if foo() {
+        bar();
+    }"],
+    );
+}
+
+#[test]
+fn ssr_blockexpr_replace_trailing_expr_with_stmt() {
+    assert_ssr_transform(
+        "if $a() {$b;} ==>> $b;",
+        "{
+    if foo() {
+        bar();
+    }
+}",
+        expect![["{
+    bar();
+}"]],
+    );
+}
+
+#[test]
 fn ssr_function_to_method() {
     assert_ssr_transform(
         "my_function($a, $b) ==>> ($a).my_method($b)",
diff --git a/crates/syntax/Cargo.toml b/crates/syntax/Cargo.toml
index 181077944..cfeaed9e6 100644
--- a/crates/syntax/Cargo.toml
+++ b/crates/syntax/Cargo.toml
@@ -13,7 +13,7 @@ doctest = false
 [dependencies]
 itertools = "0.10.0"
 rowan = "0.10.0"
-rustc_lexer = { version = "695.0.0", package = "rustc-ap-rustc_lexer" }
+rustc_lexer = { version = "697.0.0", package = "rustc-ap-rustc_lexer" }
 rustc-hash = "1.1.0"
 arrayvec = "0.5.1"
 once_cell = "1.3.1"
diff --git a/crates/tt/src/buffer.rs b/crates/tt/src/buffer.rs
index 02c771f70..3606c887d 100644
--- a/crates/tt/src/buffer.rs
+++ b/crates/tt/src/buffer.rs
@@ -1,6 +1,6 @@
 //! FIXME: write short doc here
 
-use crate::{Subtree, TokenTree};
+use crate::{Leaf, Subtree, TokenTree};
 
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 struct EntryId(usize);
@@ -13,7 +13,7 @@ struct EntryPtr(EntryId, usize);
 #[derive(Debug)]
 enum Entry<'t> {
     // Mimicking types from proc-macro.
-    Subtree(&'t TokenTree, EntryId),
+    Subtree(Option<&'t TokenTree>, &'t Subtree, EntryId),
     Leaf(&'t TokenTree),
     // End entries contain a pointer to the entry from the containing
     // token tree, or None if this is the outermost level.
@@ -27,37 +27,64 @@ pub struct TokenBuffer<'t> {
     buffers: Vec<Box<[Entry<'t>]>>,
 }
 
-impl<'t> TokenBuffer<'t> {
-    pub fn new(tokens: &'t [TokenTree]) -> TokenBuffer<'t> {
-        let mut buffers = vec![];
-
-        let idx = TokenBuffer::new_inner(tokens, &mut buffers, None);
-        assert_eq!(idx, 0);
-
-        TokenBuffer { buffers }
-    }
+trait TokenList<'a> {
+    fn entries(&self) -> (Vec<(usize, (&'a Subtree, Option<&'a TokenTree>))>, Vec<Entry<'a>>);
+}
 
-    fn new_inner(
-        tokens: &'t [TokenTree],
-        buffers: &mut Vec<Box<[Entry<'t>]>>,
-        next: Option<EntryPtr>,
-    ) -> usize {
+impl<'a> TokenList<'a> for &'a [TokenTree] {
+    fn entries(&self) -> (Vec<(usize, (&'a Subtree, Option<&'a TokenTree>))>, Vec<Entry<'a>>) {
         // Must contain everything in tokens and then the Entry::End
-        let start_capacity = tokens.len() + 1;
+        let start_capacity = self.len() + 1;
         let mut entries = Vec::with_capacity(start_capacity);
         let mut children = vec![];
-
-        for (idx, tt) in tokens.iter().enumerate() {
+        for (idx, tt) in self.iter().enumerate() {
             match tt {
                 TokenTree::Leaf(_) => {
                     entries.push(Entry::Leaf(tt));
                 }
                 TokenTree::Subtree(subtree) => {
                     entries.push(Entry::End(None));
-                    children.push((idx, (subtree, tt)));
+                    children.push((idx, (subtree, Some(tt))));
                 }
             }
         }
+        (children, entries)
+    }
+}
+
+impl<'a> TokenList<'a> for &'a Subtree {
+    fn entries(&self) -> (Vec<(usize, (&'a Subtree, Option<&'a TokenTree>))>, Vec<Entry<'a>>) {
+        // Must contain everything in tokens and then the Entry::End
+        let mut entries = vec![];
+        let mut children = vec![];
+        entries.push(Entry::End(None));
+        children.push((0usize, (*self, None)));
+        (children, entries)
+    }
+}
+
+impl<'t> TokenBuffer<'t> {
+    pub fn from_tokens(tokens: &'t [TokenTree]) -> TokenBuffer<'t> {
+        Self::new(tokens)
+    }
+
+    pub fn from_subtree(subtree: &'t Subtree) -> TokenBuffer<'t> {
+        Self::new(subtree)
+    }
+
+    fn new<T: TokenList<'t>>(tokens: T) -> TokenBuffer<'t> {
+        let mut buffers = vec![];
+        let idx = TokenBuffer::new_inner(tokens, &mut buffers, None);
+        assert_eq!(idx, 0);
+        TokenBuffer { buffers }
+    }
+
+    fn new_inner<T: TokenList<'t>>(
+        tokens: T,
+        buffers: &mut Vec<Box<[Entry<'t>]>>,
+        next: Option<EntryPtr>,
+    ) -> usize {
+        let (children, mut entries) = tokens.entries();
 
         entries.push(Entry::End(next));
         let res = buffers.len();
@@ -65,11 +92,11 @@ impl<'t> TokenBuffer<'t> {
 
         for (child_idx, (subtree, tt)) in children {
             let idx = TokenBuffer::new_inner(
-                &subtree.token_trees,
+                subtree.token_trees.as_slice(),
                 buffers,
                 Some(EntryPtr(EntryId(res), child_idx + 1)),
             );
-            buffers[res].as_mut()[child_idx] = Entry::Subtree(tt, EntryId(idx));
+            buffers[res].as_mut()[child_idx] = Entry::Subtree(tt, subtree, EntryId(idx));
         }
 
         res
@@ -87,6 +114,24 @@ impl<'t> TokenBuffer<'t> {
     }
 }
 
+#[derive(Debug)]
+pub enum TokenTreeRef<'a> {
+    Subtree(&'a Subtree, Option<&'a TokenTree>),
+    Leaf(&'a Leaf, &'a TokenTree),
+}
+
+impl<'a> TokenTreeRef<'a> {
+    pub fn cloned(&self) -> TokenTree {
+        match &self {
+            TokenTreeRef::Subtree(subtree, tt) => match tt {
+                Some(it) => (*it).clone(),
+                None => (*subtree).clone().into(),
+            },
+            TokenTreeRef::Leaf(_, tt) => (*tt).clone(),
+        }
+    }
+}
+
 /// A safe version of `Cursor` from `syn` crate https://github.com/dtolnay/syn/blob/6533607f91686545cb034d2838beea338d9d0742/src/buffer.rs#L125
 #[derive(Copy, Clone, Debug)]
 pub struct Cursor<'a> {
@@ -114,12 +159,11 @@ impl<'a> Cursor<'a> {
         match self.entry() {
             Some(Entry::End(Some(ptr))) => {
                 let idx = ptr.1;
-                if let Some(Entry::Subtree(TokenTree::Subtree(subtree), _)) =
+                if let Some(Entry::Subtree(_, subtree, _)) =
                     self.buffer.entry(&EntryPtr(ptr.0, idx - 1))
                 {
                     return Some(subtree);
                 }
-
                 None
             }
             _ => None,
@@ -134,7 +178,7 @@ impl<'a> Cursor<'a> {
     /// a cursor into that subtree
     pub fn subtree(self) -> Option<Cursor<'a>> {
         match self.entry() {
-            Some(Entry::Subtree(_, entry_id)) => {
+            Some(Entry::Subtree(_, _, entry_id)) => {
                 Some(Cursor::create(self.buffer, EntryPtr(*entry_id, 0)))
             }
             _ => None,
@@ -142,10 +186,13 @@ impl<'a> Cursor<'a> {
     }
 
     /// If the cursor is pointing at a `TokenTree`, returns it
-    pub fn token_tree(self) -> Option<&'a TokenTree> {
+    pub fn token_tree(self) -> Option<TokenTreeRef<'a>> {
         match self.entry() {
-            Some(Entry::Leaf(tt)) => Some(tt),
-            Some(Entry::Subtree(tt, _)) => Some(tt),
+            Some(Entry::Leaf(tt)) => match tt {
+                TokenTree::Leaf(leaf) => Some(TokenTreeRef::Leaf(leaf, *tt)),
+                TokenTree::Subtree(subtree) => Some(TokenTreeRef::Subtree(subtree, Some(tt))),
+            },
+            Some(Entry::Subtree(tt, subtree, _)) => Some(TokenTreeRef::Subtree(subtree, *tt)),
             Some(Entry::End(_)) => None,
             None => None,
         }
@@ -172,7 +219,7 @@ impl<'a> Cursor<'a> {
     /// a cursor into that subtree
     pub fn bump_subtree(self) -> Cursor<'a> {
         match self.entry() {
-            Some(Entry::Subtree(_, _)) => self.subtree().unwrap(),
+            Some(Entry::Subtree(_, _, _)) => self.subtree().unwrap(),
             _ => self.bump(),
         }
     }