21 files changed, 354 insertions, 120 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 506efdad0..aca737627 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -496,9 +496,9 @@ dependencies = [
 
 [[package]]
 name = "insta"
-version = "0.15.0"
+version = "0.16.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8de3f029212a3fe78a6090f1f2b993877ca245a9ded863f3fcbd6eae084fc1ed"
+checksum = "8386e795fb3927131ea4cede203c529a333652eb6dc4ff29616b832b27e9b096"
 dependencies = [
  "console",
  "difference",
diff --git a/crates/ra_assists/src/doc_tests/generated.rs b/crates/ra_assists/src/doc_tests/generated.rs
index b63b4d81a..b39e60870 100644
--- a/crates/ra_assists/src/doc_tests/generated.rs
+++ b/crates/ra_assists/src/doc_tests/generated.rs
@@ -78,7 +78,7 @@ fn foo() {
 }
 
 fn bar(arg: &str, baz: Baz) {
-    unimplemented!()
+    todo!()
 }
 
 "#####,
diff --git a/crates/ra_assists/src/handlers/add_function.rs b/crates/ra_assists/src/handlers/add_function.rs
index 488bae08f..ad4ab66ed 100644
--- a/crates/ra_assists/src/handlers/add_function.rs
+++ b/crates/ra_assists/src/handlers/add_function.rs
@@ -29,7 +29,7 @@ use rustc_hash::{FxHashMap, FxHashSet};
 // }
 //
 // fn bar(arg: &str, baz: Baz) {
-//     unimplemented!()
+//     todo!()
 // }
 //
 // ```
@@ -80,7 +80,7 @@ impl FunctionBuilder {
         Some(Self { append_fn_at, fn_name, type_params, params })
     }
     fn render(self) -> Option<FunctionTemplate> {
-        let placeholder_expr = ast::make::expr_unimplemented();
+        let placeholder_expr = ast::make::expr_todo();
         let fn_body = ast::make::block_expr(vec![], Some(placeholder_expr));
         let fn_def = ast::make::fn_def(self.fn_name, self.type_params, self.params, fn_body);
         let fn_def = ast::make::add_newlines(2, fn_def);
@@ -225,7 +225,7 @@ fn foo() {
 }
 
 fn bar() {
-    <|>unimplemented!()
+    <|>todo!()
 }
 ",
         )
@@ -252,7 +252,7 @@ impl Foo {
 }
 
 fn bar() {
-    <|>unimplemented!()
+    <|>todo!()
 }
 ",
         )
@@ -276,7 +276,7 @@ fn foo1() {
 }
 
 fn bar() {
-    <|>unimplemented!()
+    <|>todo!()
 }
 
 fn foo2() {}
@@ -302,7 +302,7 @@ mod baz {
     }
 
     fn bar() {
-        <|>unimplemented!()
+        <|>todo!()
     }
 }
 ",
@@ -315,20 +315,20 @@ mod baz {
             add_function,
             r"
 struct Baz;
-fn baz() -> Baz { unimplemented!() }
+fn baz() -> Baz { todo!() }
 fn foo() {
     bar<|>(baz());
 }
 ",
             r"
 struct Baz;
-fn baz() -> Baz { unimplemented!() }
+fn baz() -> Baz { todo!() }
 fn foo() {
     bar(baz());
 }
 
 fn bar(baz: Baz) {
-    <|>unimplemented!()
+    <|>todo!()
 }
 ",
         );
@@ -361,7 +361,7 @@ impl Baz {
 }
 
 fn bar(baz: Baz) {
-    <|>unimplemented!()
+    <|>todo!()
 }
 ",
         )
@@ -382,7 +382,7 @@ fn foo() {
 }
 
 fn bar(arg: &str) {
-    <|>unimplemented!()
+    <|>todo!()
 }
 "#,
         )
@@ -403,7 +403,7 @@ fn foo() {
 }
 
 fn bar(arg: char) {
-    <|>unimplemented!()
+    <|>todo!()
 }
 "#,
         )
@@ -424,7 +424,7 @@ fn foo() {
 }
 
 fn bar(arg: i32) {
-    <|>unimplemented!()
+    <|>todo!()
 }
 ",
         )
@@ -445,7 +445,7 @@ fn foo() {
 }
 
 fn bar(arg: u8) {
-    <|>unimplemented!()
+    <|>todo!()
 }
 ",
         )
@@ -470,7 +470,7 @@ fn foo() {
 }
 
 fn bar(x: u8) {
-    <|>unimplemented!()
+    <|>todo!()
 }
 ",
         )
@@ -493,7 +493,7 @@ fn foo() {
 }
 
 fn bar(worble: ()) {
-    <|>unimplemented!()
+    <|>todo!()
 }
 ",
         )
@@ -506,7 +506,7 @@ fn bar(worble: ()) {
             r"
 trait Foo {}
 fn foo() -> impl Foo {
-    unimplemented!()
+    todo!()
 }
 fn baz() {
     <|>bar(foo())
@@ -515,14 +515,14 @@ fn baz() {
             r"
 trait Foo {}
 fn foo() -> impl Foo {
-    unimplemented!()
+    todo!()
 }
 fn baz() {
     bar(foo())
 }
 
 fn bar(foo: impl Foo) {
-    <|>unimplemented!()
+    <|>todo!()
 }
 ",
         )
@@ -556,7 +556,7 @@ mod Foo {
     }
 
     fn bar(baz: super::Baz::Bof) {
-        <|>unimplemented!()
+        <|>todo!()
     }
 }
 ",
@@ -580,7 +580,7 @@ fn foo<T>(t: T) {
 }
 
 fn bar<T>(t: T) {
-    <|>unimplemented!()
+    <|>todo!()
 }
 ",
         )
@@ -611,7 +611,7 @@ fn foo() {
 }
 
 fn bar(arg: fn() -> Baz) {
-    <|>unimplemented!()
+    <|>todo!()
 }
 ",
         )
@@ -636,7 +636,7 @@ fn foo() {
 }
 
 fn bar(closure: impl Fn(i64) -> i64) {
-    <|>unimplemented!()
+    <|>todo!()
 }
 ",
         )
@@ -657,7 +657,7 @@ fn foo() {
 }
 
 fn bar(baz: ()) {
-    <|>unimplemented!()
+    <|>todo!()
 }
 ",
         )
@@ -682,7 +682,7 @@ fn foo() {
 }
 
 fn bar(baz_1: Baz, baz_2: Baz) {
-    <|>unimplemented!()
+    <|>todo!()
 }
 ",
         )
@@ -707,7 +707,7 @@ fn foo() {
 }
 
 fn bar(baz_1: Baz, baz_2: Baz, arg_1: &str, arg_2: &str) {
-    <|>unimplemented!()
+    <|>todo!()
 }
 "#,
         )
@@ -779,7 +779,7 @@ impl Foo {
         self.bar();
     }
     fn bar(&self) {
-        unimplemented!();
+        todo!();
     }
 }
         ",
diff --git a/crates/ra_assists/src/handlers/merge_imports.rs b/crates/ra_assists/src/handlers/merge_imports.rs
index 0958f52f1..ef0ce0586 100644
--- a/crates/ra_assists/src/handlers/merge_imports.rs
+++ b/crates/ra_assists/src/handlers/merge_imports.rs
@@ -1,7 +1,7 @@
 use std::iter::successors;
 
 use ra_syntax::{
-    algo::{neighbor, SyntaxRewriter},
+    algo::{neighbor, skip_trivia_token, SyntaxRewriter},
     ast::{self, edit::AstNodeEdit, make},
     AstNode, Direction, InsertPosition, SyntaxElement, T,
 };
@@ -72,9 +72,18 @@ fn try_merge_trees(old: &ast::UseTree, new: &ast::UseTree) -> Option<ast::UseTre
     let lhs = old.split_prefix(&lhs_prefix);
     let rhs = new.split_prefix(&rhs_prefix);
 
+    let should_insert_comma = lhs
+        .use_tree_list()?
+        .r_curly_token()
+        .and_then(|it| skip_trivia_token(it.prev_token()?, Direction::Prev))
+        .map(|it| it.kind() != T![,])
+        .unwrap_or(true);
+
     let mut to_insert: Vec<SyntaxElement> = Vec::new();
-    to_insert.push(make::token(T![,]).into());
-    to_insert.push(make::tokens::single_space().into());
+    if should_insert_comma {
+        to_insert.push(make::token(T![,]).into());
+        to_insert.push(make::tokens::single_space().into());
+    }
     to_insert.extend(
         rhs.use_tree_list()?
             .syntax()
@@ -247,4 +256,22 @@ use {
 ",
         );
     }
+
+    #[test]
+    fn test_double_comma() {
+        check_assist(
+            merge_imports,
+            r"
+use foo::bar::baz;
+use foo::<|>{
+    FooBar,
+};
+",
+            r"
+use foo::{<|>
+    FooBar,
+bar::baz};
+",
+        )
+    }
 }
diff --git a/crates/ra_flycheck/Cargo.toml b/crates/ra_flycheck/Cargo.toml
index c9a9ddc12..76e5cada4 100644
--- a/crates/ra_flycheck/Cargo.toml
+++ b/crates/ra_flycheck/Cargo.toml
@@ -13,4 +13,4 @@ serde_json = "1.0.48"
 jod-thread = "0.1.1"
 
 [dev-dependencies]
-insta = "0.15.0"
+insta = "0.16.0"
diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index 9baebf643..3801fce23 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -25,7 +25,7 @@ use hir_ty::{
     autoderef, display::HirFormatter, expr::ExprValidator, method_resolution, ApplicationTy,
     Canonical, InEnvironment, Substs, TraitEnvironment, Ty, TyDefId, TypeCtor,
 };
-use ra_db::{CrateId, Edition, FileId};
+use ra_db::{CrateId, CrateName, Edition, FileId};
 use ra_prof::profile;
 use ra_syntax::{
     ast::{self, AttrsOwner, NameOwner},
@@ -91,6 +91,10 @@ impl Crate {
         db.crate_graph()[self.id].edition
     }
 
+    pub fn display_name(self, db: &dyn HirDatabase) -> Option<CrateName> {
+        db.crate_graph()[self.id].display_name.as_ref().cloned()
+    }
+
     pub fn all(db: &dyn HirDatabase) -> Vec<Crate> {
         db.crate_graph().iter().map(|id| Crate { id }).collect()
     }
diff --git a/crates/ra_hir_def/Cargo.toml b/crates/ra_hir_def/Cargo.toml
index 56e791e3e..b85358308 100644
--- a/crates/ra_hir_def/Cargo.toml
+++ b/crates/ra_hir_def/Cargo.toml
@@ -28,4 +28,4 @@ ra_cfg = { path = "../ra_cfg" }
 tt = { path = "../ra_tt", package = "ra_tt" }
 
 [dev-dependencies]
-insta = "0.15.0"
+insta = "0.16.0"
diff --git a/crates/ra_hir_def/src/body/lower.rs b/crates/ra_hir_def/src/body/lower.rs
index 6caa87db4..79abe55ce 100644
--- a/crates/ra_hir_def/src/body/lower.rs
+++ b/crates/ra_hir_def/src/body/lower.rs
@@ -33,6 +33,7 @@ use crate::{
 };
 
 use super::{ExprSource, PatSource};
+use ast::AstChildren;
 
 pub(super) fn lower(
     db: &dyn DefDatabase,
@@ -598,8 +599,8 @@ impl ExprCollector<'_> {
             }
             ast::Pat::TupleStructPat(p) => {
                 let path = p.path().and_then(|path| self.expander.parse_path(path));
-                let args = p.args().map(|p| self.collect_pat(p)).collect();
-                Pat::TupleStruct { path, args }
+                let (args, ellipsis) = self.collect_tuple_pat(p.args());
+                Pat::TupleStruct { path, args, ellipsis }
             }
             ast::Pat::RefPat(p) => {
                 let pat = self.collect_pat_opt(p.pat());
@@ -616,10 +617,10 @@ impl ExprCollector<'_> {
             }
             ast::Pat::ParenPat(p) => return self.collect_pat_opt(p.pat()),
             ast::Pat::TuplePat(p) => {
-                let args = p.args().map(|p| self.collect_pat(p)).collect();
-                Pat::Tuple(args)
+                let (args, ellipsis) = self.collect_tuple_pat(p.args());
+                Pat::Tuple { args, ellipsis }
             }
-            ast::Pat::PlaceholderPat(_) | ast::Pat::DotDotPat(_) => Pat::Wild,
+            ast::Pat::PlaceholderPat(_) => Pat::Wild,
             ast::Pat::RecordPat(p) => {
                 let path = p.path().and_then(|path| self.expander.parse_path(path));
                 let record_field_pat_list =
@@ -665,6 +666,9 @@ impl ExprCollector<'_> {
                     Pat::Missing
                 }
             }
+            ast::Pat::DotDotPat(_) => unreachable!(
+                "`DotDotPat` requires special handling and should not be mapped to a Pat."
+            ),
             // FIXME: implement
             ast::Pat::BoxPat(_) | ast::Pat::RangePat(_) | ast::Pat::MacroPat(_) => Pat::Missing,
         };
@@ -679,6 +683,19 @@ impl ExprCollector<'_> {
             self.missing_pat()
         }
     }
+
+    fn collect_tuple_pat(&mut self, args: AstChildren<ast::Pat>) -> (Vec<PatId>, Option<usize>) {
+        // Find the location of the `..`, if there is one. Note that we do not
+        // consider the possiblity of there being multiple `..` here.
+        let ellipsis = args.clone().position(|p| matches!(p, ast::Pat::DotDotPat(_)));
+        // We want to skip the `..` pattern here, since we account for it above.
+        let args = args
+            .filter(|p| !matches!(p, ast::Pat::DotDotPat(_)))
+            .map(|p| self.collect_pat(p))
+            .collect();
+
+        (args, ellipsis)
+    }
 }
 
 impl From<ast::BinOp> for BinaryOp {
diff --git a/crates/ra_hir_def/src/expr.rs b/crates/ra_hir_def/src/expr.rs
index e11bdf3ec..a0cdad529 100644
--- a/crates/ra_hir_def/src/expr.rs
+++ b/crates/ra_hir_def/src/expr.rs
@@ -374,7 +374,7 @@ pub struct RecordFieldPat {
 pub enum Pat {
     Missing,
     Wild,
-    Tuple(Vec<PatId>),
+    Tuple { args: Vec<PatId>, ellipsis: Option<usize> },
     Or(Vec<PatId>),
     Record { path: Option<Path>, args: Vec<RecordFieldPat>, ellipsis: bool },
     Range { start: ExprId, end: ExprId },
@@ -382,7 +382,7 @@ pub enum Pat {
     Path(Path),
     Lit(ExprId),
     Bind { mode: BindingAnnotation, name: Name, subpat: Option<PatId> },
-    TupleStruct { path: Option<Path>, args: Vec<PatId> },
+    TupleStruct { path: Option<Path>, args: Vec<PatId>, ellipsis: Option<usize> },
     Ref { pat: PatId, mutability: Mutability },
 }
 
@@ -393,7 +393,7 @@ impl Pat {
             Pat::Bind { subpat, .. } => {
                 subpat.iter().copied().for_each(f);
             }
-            Pat::Or(args) | Pat::Tuple(args) | Pat::TupleStruct { args, .. } => {
+            Pat::Or(args) | Pat::Tuple { args, .. } | Pat::TupleStruct { args, .. } => {
                 args.iter().copied().for_each(f);
             }
             Pat::Ref { pat, .. } => f(*pat),
diff --git a/crates/ra_hir_ty/Cargo.toml b/crates/ra_hir_ty/Cargo.toml
index aaee235d8..0003456c1 100644
--- a/crates/ra_hir_ty/Cargo.toml
+++ b/crates/ra_hir_ty/Cargo.toml
@@ -31,4 +31,4 @@ chalk-rust-ir = { git = "https://github.com/rust-lang/chalk.git", rev = "6222e41
 chalk-ir =      { git = "https://github.com/rust-lang/chalk.git", rev = "6222e416b96892b2a86bc08de7dbc9826ff1acea" }
 
 [dev-dependencies]
-insta = "0.15.0"
+insta = "0.16.0"
diff --git a/crates/ra_hir_ty/src/_match.rs b/crates/ra_hir_ty/src/_match.rs
index c482cf619..a64be9848 100644
--- a/crates/ra_hir_ty/src/_match.rs
+++ b/crates/ra_hir_ty/src/_match.rs
@@ -289,7 +289,7 @@ impl PatStack {
         Self::from_slice(&self.0[1..])
     }
 
-    fn replace_head_with(&self, pat_ids: &[PatId]) -> PatStack {
+    fn replace_head_with<T: Into<PatIdOrWild> + Copy>(&self, pat_ids: &[T]) -> PatStack {
         let mut patterns: PatStackInner = smallvec![];
         for pat in pat_ids {
             patterns.push((*pat).into());
@@ -320,12 +320,14 @@ impl PatStack {
         constructor: &Constructor,
     ) -> MatchCheckResult<Option<PatStack>> {
         let result = match (self.head().as_pat(cx), constructor) {
-            (Pat::Tuple(ref pat_ids), Constructor::Tuple { arity }) => {
-                debug_assert_eq!(
-                    pat_ids.len(),
-                    *arity,
-                    "we type check before calling this code, so we should never hit this case",
-                );
+            (Pat::Tuple { args: ref pat_ids, ellipsis }, Constructor::Tuple { arity: _ }) => {
+                if ellipsis.is_some() {
+                    // If there are ellipsis here, we should add the correct number of
+                    // Pat::Wild patterns to `pat_ids`. We should be able to use the
+                    // constructors arity for this, but at the time of writing we aren't
+                    // correctly calculating this arity when ellipsis are present.
+                    return Err(MatchCheckErr::NotImplemented);
+                }
 
                 Some(self.replace_head_with(pat_ids))
             }
@@ -351,19 +353,47 @@ impl PatStack {
                     Some(self.to_tail())
                 }
             }
-            (Pat::TupleStruct { args: ref pat_ids, .. }, Constructor::Enum(enum_constructor)) => {
+            (
+                Pat::TupleStruct { args: ref pat_ids, ellipsis, .. },
+                Constructor::Enum(enum_constructor),
+            ) => {
                 let pat_id = self.head().as_id().expect("we know this isn't a wild");
                 if !enum_variant_matches(cx, pat_id, *enum_constructor) {
                     None
                 } else {
-                    // If the enum variant matches, then we need to confirm
-                    // that the number of patterns aligns with the expected
-                    // number of patterns for that enum variant.
-                    if pat_ids.len() != constructor.arity(cx)? {
-                        return Err(MatchCheckErr::MalformedMatchArm);
+                    let constructor_arity = constructor.arity(cx)?;
+                    if let Some(ellipsis_position) = ellipsis {
+                        // If there are ellipsis in the pattern, the ellipsis must take the place
+                        // of at least one sub-pattern, so `pat_ids` should be smaller than the
+                        // constructor arity.
+                        if pat_ids.len() < constructor_arity {
+                            let mut new_patterns: Vec<PatIdOrWild> = vec![];
+
+                            for pat_id in &pat_ids[0..ellipsis_position] {
+                                new_patterns.push((*pat_id).into());
+                            }
+
+                            for _ in 0..(constructor_arity - pat_ids.len()) {
+                                new_patterns.push(PatIdOrWild::Wild);
+                            }
+
+                            for pat_id in &pat_ids[ellipsis_position..pat_ids.len()] {
+                                new_patterns.push((*pat_id).into());
+                            }
+
+                            Some(self.replace_head_with(&new_patterns))
+                        } else {
+                            return Err(MatchCheckErr::MalformedMatchArm);
+                        }
+                    } else {
+                        // If there is no ellipsis in the tuple pattern, the number
+                        // of patterns must equal the constructor arity.
+                        if pat_ids.len() == constructor_arity {
+                            Some(self.replace_head_with(pat_ids))
+                        } else {
+                            return Err(MatchCheckErr::MalformedMatchArm);
+                        }
                     }
-
-                    Some(self.replace_head_with(pat_ids))
                 }
             }
             (Pat::Or(_), _) => return Err(MatchCheckErr::NotImplemented),
@@ -644,7 +674,11 @@ impl Constructor {
 fn pat_constructor(cx: &MatchCheckCtx, pat: PatIdOrWild) -> MatchCheckResult<Option<Constructor>> {
     let res = match pat.as_pat(cx) {
         Pat::Wild => None,
-        Pat::Tuple(pats) => Some(Constructor::Tuple { arity: pats.len() }),
+        // FIXME somehow create the Tuple constructor with the proper arity. If there are
+        // ellipsis, the arity is not equal to the number of patterns.
+        Pat::Tuple { args: pats, ellipsis } if ellipsis.is_none() => {
+            Some(Constructor::Tuple { arity: pats.len() })
+        }
         Pat::Lit(lit_expr) => match cx.body.exprs[lit_expr] {
             Expr::Literal(Literal::Bool(val)) => Some(Constructor::Bool(val)),
             _ => return Err(MatchCheckErr::NotImplemented),
@@ -1507,6 +1541,67 @@ mod tests {
     }
 
     #[test]
+    fn enum_tuple_partial_ellipsis_2_no_diagnostic() {
+        let content = r"
+            enum Either {
+                A(bool, bool, bool, bool),
+                B,
+            }
+            fn test_fn() {
+                match Either::B {
+                    Either::A(true, .., true) => {},
+                    Either::A(true, .., false) => {},
+                    Either::A(.., true) => {},
+                    Either::A(.., false) => {},
+                    Either::B => {},
+                }
+            }
+        ";
+
+        check_no_diagnostic(content);
+    }
+
+    #[test]
+    fn enum_tuple_partial_ellipsis_missing_arm() {
+        let content = r"
+            enum Either {
+                A(bool, bool, bool, bool),
+                B,
+            }
+            fn test_fn() {
+                match Either::B {
+                    Either::A(true, .., true) => {},
+                    Either::A(true, .., false) => {},
+                    Either::A(false, .., false) => {},
+                    Either::B => {},
+                }
+            }
+        ";
+
+        check_diagnostic(content);
+    }
+
+    #[test]
+    fn enum_tuple_partial_ellipsis_2_missing_arm() {
+        let content = r"
+            enum Either {
+                A(bool, bool, bool, bool),
+                B,
+            }
+            fn test_fn() {
+                match Either::B {
+                    Either::A(true, .., true) => {},
+                    Either::A(true, .., false) => {},
+                    Either::A(.., true) => {},
+                    Either::B => {},
+                }
+            }
+        ";
+
+        check_diagnostic(content);
+    }
+
+    #[test]
     fn enum_tuple_ellipsis_no_diagnostic() {
         let content = r"
             enum Either {
@@ -1645,11 +1740,7 @@ mod false_negatives {
         ";
 
         // This is a false negative.
-        // The `..` pattern is currently lowered to a single `Pat::Wild`
-        // no matter how many fields the `..` pattern is covering. This
-        // causes the match arm in this test not to type check against
-        // the match expression, which causes this diagnostic not to
-        // fire.
+        // We don't currently handle tuple patterns with ellipsis.
         check_no_diagnostic(content);
     }
 
@@ -1664,32 +1755,7 @@ mod false_negatives {
         ";
 
         // This is a false negative.
-        // See comments on `tuple_of_bools_with_ellipsis_at_end_missing_arm`.
-        check_no_diagnostic(content);
-    }
-
-    #[test]
-    fn enum_tuple_partial_ellipsis_missing_arm() {
-        let content = r"
-            enum Either {
-                A(bool, bool, bool, bool),
-                B,
-            }
-            fn test_fn() {
-                match Either::B {
-                    Either::A(true, .., true) => {},
-                    Either::A(true, .., false) => {},
-                    Either::A(false, .., false) => {},
-                    Either::B => {},
-                }
-            }
-        ";
-
-        // This is a false negative.
-        // The `..` pattern is currently lowered to a single `Pat::Wild`
-        // no matter how many fields the `..` pattern is covering. This
-        // causes us to return a `MatchCheckErr::MalformedMatchArm` in
-        // `Pat::specialize_constructor`.
+        // We don't currently handle tuple patterns with ellipsis.
         check_no_diagnostic(content);
     }
 }
diff --git a/crates/ra_hir_ty/src/infer/pat.rs b/crates/ra_hir_ty/src/infer/pat.rs
index 078476f76..8ec4d4ace 100644
--- a/crates/ra_hir_ty/src/infer/pat.rs
+++ b/crates/ra_hir_ty/src/infer/pat.rs
@@ -85,7 +85,7 @@ impl<'a> InferenceContext<'a> {
         let body = Arc::clone(&self.body); // avoid borrow checker problem
 
         let is_non_ref_pat = match &body[pat] {
-            Pat::Tuple(..)
+            Pat::Tuple { .. }
             | Pat::Or(..)
             | Pat::TupleStruct { .. }
             | Pat::Record { .. }
@@ -116,7 +116,7 @@ impl<'a> InferenceContext<'a> {
         let expected = expected;
 
         let ty = match &body[pat] {
-            Pat::Tuple(ref args) => {
+            Pat::Tuple { ref args, .. } => {
                 let expectations = match expected.as_tuple() {
                     Some(parameters) => &*parameters.0,
                     _ => &[],
@@ -155,7 +155,7 @@ impl<'a> InferenceContext<'a> {
                 let subty = self.infer_pat(*pat, expectation, default_bm);
                 Ty::apply_one(TypeCtor::Ref(*mutability), subty)
             }
-            Pat::TupleStruct { path: p, args: subpats } => {
+            Pat::TupleStruct { path: p, args: subpats, .. } => {
                 self.infer_tuple_struct_pat(p.as_ref(), subpats, expected, default_bm, pat)
             }
             Pat::Record { path: p, args: fields, ellipsis: _ } => {
diff --git a/crates/ra_ide/Cargo.toml b/crates/ra_ide/Cargo.toml
index b4a29b81b..05c940605 100644
--- a/crates/ra_ide/Cargo.toml
+++ b/crates/ra_ide/Cargo.toml
@@ -35,4 +35,4 @@ ra_assists = { path = "../ra_assists" }
 hir = { path = "../ra_hir", package = "ra_hir" }
 
 [dev-dependencies]
-insta = "0.15.0"
+insta = "0.16.0"
diff --git a/crates/rust-analyzer/src/bin/args.rs b/crates/rust-analyzer/src/bin/args.rs
index 3cf394bb4..f5981588a 100644
--- a/crates/rust-analyzer/src/bin/args.rs
+++ b/crates/rust-analyzer/src/bin/args.rs
@@ -35,6 +35,13 @@ pub(crate) enum Command {
         what: BenchWhat,
         load_output_dirs: bool,
     },
+    Diagnostics {
+        path: PathBuf,
+        load_output_dirs: bool,
+        /// Include files which are not modules. In rust-analyzer
+        /// this would include the parser test files.
+        all: bool,
+    },
     RunServer,
     Version,
 }
@@ -209,6 +216,38 @@ ARGS:
                 let load_output_dirs = matches.contains("--load-output-dirs");
                 Command::Bench { path, what, load_output_dirs }
             }
+            "diagnostics" => {
+                if matches.contains(["-h", "--help"]) {
+                    eprintln!(
+                        "\
+ra-cli-diagnostics
+
+USAGE:
+    rust-analyzer diagnostics [FLAGS] [PATH]
+
+FLAGS:
+    -h, --help              Prints help information
+        --load-output-dirs  Load OUT_DIR values by running `cargo check` before analysis
+        --all               Include all files rather than only modules
+
+ARGS:
+    <PATH>"
+                    );
+                    return Ok(Err(HelpPrinted));
+                }
+
+                let load_output_dirs = matches.contains("--load-output-dirs");
+                let all = matches.contains("--all");
+                let path = {
+                    let mut trailing = matches.free()?;
+                    if trailing.len() != 1 {
+                        bail!("Invalid flags");
+                    }
+                    trailing.pop().unwrap().into()
+                };
+
+                Command::Diagnostics { path, load_output_dirs, all }
+            }
             _ => {
                 eprintln!(
                     "\
diff --git a/crates/rust-analyzer/src/bin/main.rs b/crates/rust-analyzer/src/bin/main.rs
index 608f4f67b..7cfc44f01 100644
--- a/crates/rust-analyzer/src/bin/main.rs
+++ b/crates/rust-analyzer/src/bin/main.rs
@@ -39,6 +39,10 @@ fn main() -> Result<()> {
             cli::analysis_bench(args.verbosity, path.as_ref(), what, load_output_dirs)?
         }
 
+        args::Command::Diagnostics { path, load_output_dirs, all } => {
+            cli::diagnostics(path.as_ref(), load_output_dirs, all)?
+        }
+
         args::Command::RunServer => run_server()?,
         args::Command::Version => println!("rust-analyzer {}", env!("REV")),
     }
diff --git a/crates/rust-analyzer/src/cli.rs b/crates/rust-analyzer/src/cli.rs
index c9738d101..a865a7c7e 100644
--- a/crates/rust-analyzer/src/cli.rs
+++ b/crates/rust-analyzer/src/cli.rs
@@ -3,6 +3,7 @@
 mod load_cargo;
 mod analysis_stats;
 mod analysis_bench;
+mod diagnostics;
 mod progress_report;
 
 use std::io::Read;
@@ -12,6 +13,10 @@ use ra_ide::{file_structure, Analysis};
 use ra_prof::profile;
 use ra_syntax::{AstNode, SourceFile};
 
+pub use analysis_bench::{analysis_bench, BenchWhat, Position};
+pub use analysis_stats::analysis_stats;
+pub use diagnostics::diagnostics;
+
 #[derive(Clone, Copy)]
 pub enum Verbosity {
     Spammy,
@@ -60,9 +65,6 @@ pub fn highlight(rainbow: bool) -> Result<()> {
     Ok(())
 }
 
-pub use analysis_bench::{analysis_bench, BenchWhat, Position};
-pub use analysis_stats::analysis_stats;
-
 fn file() -> Result<SourceFile> {
     let text = read_stdin()?;
     Ok(SourceFile::parse(&text).tree())
diff --git a/crates/rust-analyzer/src/cli/diagnostics.rs b/crates/rust-analyzer/src/cli/diagnostics.rs
new file mode 100644
index 000000000..92664b415
--- /dev/null
+++ b/crates/rust-analyzer/src/cli/diagnostics.rs
@@ -0,0 +1,74 @@
+//! Analyze all modules in a project for diagnostics. Exits with a non-zero status
+//! code if any errors are found.
+
+use anyhow::anyhow;
+use ra_db::SourceDatabaseExt;
+use ra_ide::Severity;
+use std::{collections::HashSet, path::Path};
+
+use crate::cli::{load_cargo::load_cargo, Result};
+use hir::Semantics;
+
+pub fn diagnostics(path: &Path, load_output_dirs: bool, all: bool) -> Result<()> {
+    let (host, roots) = load_cargo(path, load_output_dirs)?;
+    let db = host.raw_database();
+    let analysis = host.analysis();
+    let semantics = Semantics::new(db);
+    let members = roots
+        .into_iter()
+        .filter_map(|(source_root_id, project_root)| {
+            // filter out dependencies
+            if project_root.is_member() {
+                Some(source_root_id)
+            } else {
+                None
+            }
+        })
+        .collect::<HashSet<_>>();
+
+    let mut found_error = false;
+    let mut visited_files = HashSet::new();
+    for source_root_id in members {
+        for file_id in db.source_root(source_root_id).walk() {
+            // Filter out files which are not actually modules (unless `--all` flag is
+            // passed). In the rust-analyzer repository this filters out the parser test files.
+            if semantics.to_module_def(file_id).is_some() || all {
+                if !visited_files.contains(&file_id) {
+                    let crate_name = if let Some(module) = semantics.to_module_def(file_id) {
+                        if let Some(name) = module.krate().display_name(db) {
+                            format!("{}", name)
+                        } else {
+                            String::from("unknown")
+                        }
+                    } else {
+                        String::from("unknown")
+                    };
+                    println!(
+                        "processing crate: {}, module: {}",
+                        crate_name,
+                        db.file_relative_path(file_id)
+                    );
+                    for diagnostic in analysis.diagnostics(file_id).unwrap() {
+                        if matches!(diagnostic.severity, Severity::Error) {
+                            found_error = true;
+                        }
+
+                        println!("{:?}", diagnostic);
+                    }
+
+                    visited_files.insert(file_id);
+                }
+            }
+        }
+    }
+
+    println!();
+    println!("diagnostic scan complete");
+
+    if found_error {
+        println!();
+        Err(anyhow!("diagnostic error detected"))
+    } else {
+        Ok(())
+    }
+}
diff --git a/docs/user/assists.md b/docs/user/assists.md
index 1d9510423..6483ba4f3 100644
--- a/docs/user/assists.md
+++ b/docs/user/assists.md
@@ -77,7 +77,7 @@ fn foo() {
 }
 
 fn bar(arg: &str, baz: Baz) {
-    unimplemented!()
+    todo!()
 }
 
 ```
diff --git a/editors/code/package-lock.json b/editors/code/package-lock.json
index eb4f299a1..e11cffd68 100644
--- a/editors/code/package-lock.json
+++ b/editors/code/package-lock.json
@@ -109,9 +109,9 @@
             }
         },
         "@types/vscode": {
-            "version": "1.43.0",
-            "resolved": "https://registry.npmjs.org/@types/vscode/-/vscode-1.43.0.tgz",
-            "integrity": "sha512-kIaR9qzd80rJOxePKpCB/mdy00mz8Apt2QA5Y6rdrKFn13QNFNeP3Hzmsf37Bwh/3cS7QjtAeGSK7wSqAU0sYQ==",
+            "version": "1.44.0",
+            "resolved": "https://registry.npmjs.org/@types/vscode/-/vscode-1.44.0.tgz",
+            "integrity": "sha512-WJZtZlinE3meRdH+I7wTsIhpz/GLhqEQwmPGeh4s1irWLwMzCeTV8WZ+pgPTwrDXoafVUWwo1LiZ9HJVHFlJSQ==",
             "dev": true
         },
         "@typescript-eslint/eslint-plugin": {
@@ -1776,32 +1776,32 @@
             }
         },
         "vscode-jsonrpc": {
-            "version": "5.0.1",
-            "resolved": "https://registry.npmjs.org/vscode-jsonrpc/-/vscode-jsonrpc-5.0.1.tgz",
-            "integrity": "sha512-JvONPptw3GAQGXlVV2utDcHx0BiY34FupW/kI6mZ5x06ER5DdPG/tXWMVHjTNULF5uKPOUUD0SaXg5QaubJL0A=="
+            "version": "5.1.0-next.1",
+            "resolved": "https://registry.npmjs.org/vscode-jsonrpc/-/vscode-jsonrpc-5.1.0-next.1.tgz",
+            "integrity": "sha512-mwLDojZkbmpizSJSmp690oa9FB9jig18SIDGZeBCvFc2/LYSRvMm/WwWtMBJuJ1MfFh7rZXfQige4Uje5Z9NzA=="
         },
         "vscode-languageclient": {
-            "version": "6.1.3",
-            "resolved": "https://registry.npmjs.org/vscode-languageclient/-/vscode-languageclient-6.1.3.tgz",
-            "integrity": "sha512-YciJxk08iU5LmWu7j5dUt9/1OLjokKET6rME3cI4BRpiF6HZlusm2ZwPt0MYJ0lV5y43sZsQHhyon2xBg4ZJVA==",
+            "version": "7.0.0-next.1",
+            "resolved": "https://registry.npmjs.org/vscode-languageclient/-/vscode-languageclient-7.0.0-next.1.tgz",
+            "integrity": "sha512-JrjCUhLpQZxQ5VpWpilOHDMhVsn0fdN5jBh1uFNhSr5c2loJvRdr9Km2EuSQOFfOQsBKx0+xvY8PbsypNEcJ6w==",
             "requires": {
                 "semver": "^6.3.0",
-                "vscode-languageserver-protocol": "^3.15.3"
+                "vscode-languageserver-protocol": "3.16.0-next.2"
             }
         },
         "vscode-languageserver-protocol": {
-            "version": "3.15.3",
-            "resolved": "https://registry.npmjs.org/vscode-languageserver-protocol/-/vscode-languageserver-protocol-3.15.3.tgz",
-            "integrity": "sha512-zrMuwHOAQRhjDSnflWdJG+O2ztMWss8GqUUB8dXLR/FPenwkiBNkMIJJYfSN6sgskvsF0rHAoBowNQfbyZnnvw==",
+            "version": "3.16.0-next.2",
+            "resolved": "https://registry.npmjs.org/vscode-languageserver-protocol/-/vscode-languageserver-protocol-3.16.0-next.2.tgz",
+            "integrity": "sha512-atmkGT/W6tF0cx4SaWFYtFs2UeSeC28RPiap9myv2YZTaTCFvTBEPNWrU5QRKfkyM0tbgtGo6T3UCQ8tkDpjzA==",
             "requires": {
-                "vscode-jsonrpc": "^5.0.1",
-                "vscode-languageserver-types": "3.15.1"
+                "vscode-jsonrpc": "5.1.0-next.1",
+                "vscode-languageserver-types": "3.16.0-next.1"
             }
         },
         "vscode-languageserver-types": {
-            "version": "3.15.1",
-            "resolved": "https://registry.npmjs.org/vscode-languageserver-types/-/vscode-languageserver-types-3.15.1.tgz",
-            "integrity": "sha512-+a9MPUQrNGRrGU630OGbYVQ+11iOIovjCkqxajPa9w57Sd5ruK8WQNsslzpa0x/QJqC8kRc2DUxWjIFwoNm4ZQ=="
+            "version": "3.16.0-next.1",
+            "resolved": "https://registry.npmjs.org/vscode-languageserver-types/-/vscode-languageserver-types-3.16.0-next.1.tgz",
+            "integrity": "sha512-tZFUSbyjUcrh+qQf13ALX4QDdOfDX0cVaBFgy7ktJ0VwS7AW/yRKgGPSxVqqP9OCMNPdqP57O5q47w2pEwfaUg=="
         },
         "which": {
             "version": "1.3.1",
diff --git a/editors/code/package.json b/editors/code/package.json
index 0bf7b6ae6..33bd66b40 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -34,14 +34,14 @@
     "dependencies": {
         "jsonc-parser": "^2.2.1",
         "node-fetch": "^2.6.0",
-        "vscode-languageclient": "6.1.3"
+        "vscode-languageclient": "7.0.0-next.1"
     },
     "devDependencies": {
         "@rollup/plugin-commonjs": "^11.0.2",
         "@rollup/plugin-node-resolve": "^7.1.1",
         "@types/node": "^12.12.34",
         "@types/node-fetch": "^2.5.5",
-        "@types/vscode": "^1.43.0",
+        "@types/vscode": "^1.44.0",
         "@typescript-eslint/eslint-plugin": "^2.27.0",
         "@typescript-eslint/parser": "^2.27.0",
         "eslint": "^6.8.0",
diff --git a/xtask/tests/tidy-tests/main.rs b/xtask/tests/tidy-tests/main.rs
index 4f525fcd0..101ae19bd 100644
--- a/xtask/tests/tidy-tests/main.rs
+++ b/xtask/tests/tidy-tests/main.rs
@@ -26,6 +26,7 @@ fn check_todo(path: &Path, text: &str) {
         // Some of our assists generate `todo!()` so those files are whitelisted.
         "doc_tests/generated.rs",
         "handlers/add_missing_impl_members.rs",
+        "handlers/add_function.rs",
         // To support generating `todo!()` in assists, we have `expr_todo()` in ast::make.
         "ast/make.rs",
     ];