27 files changed, 516 insertions, 145 deletions

diff --git a/crates/hir_def/Cargo.toml b/crates/hir_def/Cargo.toml
index c2d99280f..475d337f3 100644
--- a/crates/hir_def/Cargo.toml
+++ b/crates/hir_def/Cargo.toml
@@ -10,7 +10,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = "1.1"
+cov-mark = { version = "1.1", features = ["thread-local"] }
 log = "0.4.8"
 once_cell = "1.3.1"
 rustc-hash = "1.1.0"
diff --git a/crates/hir_expand/src/name.rs b/crates/hir_expand/src/name.rs
index e833e032c..43de9edd6 100644
--- a/crates/hir_expand/src/name.rs
+++ b/crates/hir_expand/src/name.rs
@@ -191,6 +191,8 @@ pub mod known {
         filter_map,
         next,
         iter_mut,
+        len,
+        is_empty,
         // Builtin macros
         file,
         column,
diff --git a/crates/hir_ty/Cargo.toml b/crates/hir_ty/Cargo.toml
index b9c93f56f..0ef27cd37 100644
--- a/crates/hir_ty/Cargo.toml
+++ b/crates/hir_ty/Cargo.toml
@@ -10,7 +10,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = "1.1"
+cov-mark = { version = "1.1", features = ["thread-local"] }
 itertools = "0.10.0"
 arrayvec = "0.5.1"
 smallvec = "1.2.0"
@@ -31,7 +31,7 @@ profile = { path = "../profile", version = "0.0.0" }
 syntax = { path = "../syntax", version = "0.0.0" }
 
 [dev-dependencies]
-test_utils = { path = "../test_utils"  }
+test_utils = { path = "../test_utils" }
 expect-test = "1.1"
 tracing = "0.1"
 tracing-subscriber = { version = "0.2", default-features = false, features = ["env-filter", "registry"] }
diff --git a/crates/ide/Cargo.toml b/crates/ide/Cargo.toml
index 6ae7c9e6c..f04bcf531 100644
--- a/crates/ide/Cargo.toml
+++ b/crates/ide/Cargo.toml
@@ -10,7 +10,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = "1.1"
+cov-mark = { version = "1.1", features = ["thread-local"] }
 either = "1.5.3"
 indexmap = "1.4.0"
 itertools = "0.10.0"
diff --git a/crates/ide_assists/Cargo.toml b/crates/ide_assists/Cargo.toml
index dd9aa27c6..a83acb191 100644
--- a/crates/ide_assists/Cargo.toml
+++ b/crates/ide_assists/Cargo.toml
@@ -10,7 +10,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = "1.1"
+cov-mark = { version = "1.1", features = ["thread-local"] }
 rustc-hash = "1.1.0"
 itertools = "0.10.0"
 either = "1.6.1"
diff --git a/crates/ide_assists/src/handlers/generate_is_empty_from_len.rs b/crates/ide_assists/src/handlers/generate_is_empty_from_len.rs
new file mode 100644
index 000000000..aa7072f25
--- /dev/null
+++ b/crates/ide_assists/src/handlers/generate_is_empty_from_len.rs
@@ -0,0 +1,255 @@
+use hir::{known, HasSource, Name};
+use syntax::{
+    ast::{self, NameOwner},
+    AstNode, TextRange,
+};
+
+use crate::{
+    assist_context::{AssistContext, Assists},
+    AssistId, AssistKind,
+};
+
+// Assist: generate_is_empty_from_len
+//
+// Generates is_empty implementation from the len method.
+//
+// ```
+// struct MyStruct { data: Vec<String> }
+//
+// impl MyStruct {
+//     p$0ub fn len(&self) -> usize {
+//         self.data.len()
+//     }
+// }
+// ```
+// ->
+// ```
+// struct MyStruct { data: Vec<String> }
+//
+// impl MyStruct {
+//     pub fn len(&self) -> usize {
+//         self.data.len()
+//     }
+//
+//     pub fn is_empty(&self) -> bool {
+//         self.len() == 0
+//     }
+// }
+// ```
+pub(crate) fn generate_is_empty_from_len(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let fn_node = ctx.find_node_at_offset::<ast::Fn>()?;
+    let fn_name = fn_node.name()?;
+
+    if fn_name.text() != "len" {
+        cov_mark::hit!(len_function_not_present);
+        return None;
+    }
+
+    if fn_node.param_list()?.params().next().is_some() {
+        cov_mark::hit!(len_function_with_parameters);
+        return None;
+    }
+
+    let impl_ = fn_node.syntax().ancestors().find_map(ast::Impl::cast)?;
+    if get_impl_method(ctx, &impl_, &known::is_empty).is_some() {
+        cov_mark::hit!(is_empty_already_implemented);
+        return None;
+    }
+
+    let range = get_text_range_of_len_function(ctx, &impl_)?;
+
+    acc.add(
+        AssistId("generate_is_empty_from_len", AssistKind::Generate),
+        "Generate a is_empty impl from a len function",
+        range,
+        |builder| {
+            let code = r#"
+
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }"#
+            .to_string();
+            builder.insert(range.end(), code)
+        },
+    )
+}
+
+fn get_impl_method(
+    ctx: &AssistContext,
+    impl_: &ast::Impl,
+    fn_name: &Name,
+) -> Option<hir::Function> {
+    let db = ctx.sema.db;
+    let impl_def: hir::Impl = ctx.sema.to_def(impl_)?;
+
+    let scope = ctx.sema.scope(impl_.syntax());
+    let krate = impl_def.module(db).krate();
+    let ty = impl_def.target_ty(db);
+    let traits_in_scope = scope.traits_in_scope();
+    ty.iterate_method_candidates(db, krate, &traits_in_scope, Some(fn_name), |_, func| Some(func))
+}
+
+fn get_text_range_of_len_function(ctx: &AssistContext, impl_: &ast::Impl) -> Option<TextRange> {
+    let db = ctx.sema.db;
+    let func = get_impl_method(ctx, impl_, &known::len)?;
+    let node = func.source(db)?;
+    Some(node.syntax().value.text_range())
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn len_function_not_present() {
+        cov_mark::check!(len_function_not_present);
+        check_assist_not_applicable(
+            generate_is_empty_from_len,
+            r#"
+struct MyStruct { data: Vec<String> }
+
+impl MyStruct {
+    p$0ub fn test(&self) -> usize {
+            self.data.len()
+        }
+    }
+"#,
+        );
+    }
+
+    #[test]
+    fn len_function_with_parameters() {
+        cov_mark::check!(len_function_with_parameters);
+        check_assist_not_applicable(
+            generate_is_empty_from_len,
+            r#"
+struct MyStruct { data: Vec<String> }
+
+impl MyStruct {
+    p$0ub fn len(&self, _i: bool) -> usize {
+        self.data.len()
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn is_empty_already_implemented() {
+        cov_mark::check!(is_empty_already_implemented);
+        check_assist_not_applicable(
+            generate_is_empty_from_len,
+            r#"
+struct MyStruct { data: Vec<String> }
+
+impl MyStruct {
+    p$0ub fn len(&self) -> usize {
+        self.data.len()
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn generate_is_empty() {
+        check_assist(
+            generate_is_empty_from_len,
+            r#"
+struct MyStruct { data: Vec<String> }
+
+impl MyStruct {
+    p$0ub fn len(&self) -> usize {
+        self.data.len()
+    }
+}
+"#,
+            r#"
+struct MyStruct { data: Vec<String> }
+
+impl MyStruct {
+    pub fn len(&self) -> usize {
+        self.data.len()
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn multiple_functions_in_impl() {
+        check_assist(
+            generate_is_empty_from_len,
+            r#"
+struct MyStruct { data: Vec<String> }
+
+impl MyStruct {
+    pub fn new() -> Self {
+        Self { data: 0 }
+    }
+
+    p$0ub fn len(&self) -> usize {
+        self.data.len()
+    }
+
+    pub fn work(&self) -> Option<usize> {
+
+    }
+}
+"#,
+            r#"
+struct MyStruct { data: Vec<String> }
+
+impl MyStruct {
+    pub fn new() -> Self {
+        Self { data: 0 }
+    }
+
+    pub fn len(&self) -> usize {
+        self.data.len()
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
+    pub fn work(&self) -> Option<usize> {
+
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn multiple_impls() {
+        check_assist_not_applicable(
+            generate_is_empty_from_len,
+            r#"
+struct MyStruct { data: Vec<String> }
+
+impl MyStruct {
+    p$0ub fn len(&self) -> usize {
+        self.data.len()
+    }
+}
+
+impl MyStruct {
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+}
+"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/lib.rs b/crates/ide_assists/src/lib.rs
index f1aab74d4..8c068a6c0 100644
--- a/crates/ide_assists/src/lib.rs
+++ b/crates/ide_assists/src/lib.rs
@@ -129,6 +129,7 @@ mod handlers {
     mod flip_trait_bound;
     mod generate_default_from_enum_variant;
     mod generate_default_from_new;
+    mod generate_is_empty_from_len;
     mod generate_derive;
     mod generate_enum_is_method;
     mod generate_enum_projection_method;
@@ -193,6 +194,7 @@ mod handlers {
             flip_trait_bound::flip_trait_bound,
             generate_default_from_enum_variant::generate_default_from_enum_variant,
             generate_default_from_new::generate_default_from_new,
+            generate_is_empty_from_len::generate_is_empty_from_len,
             generate_derive::generate_derive,
             generate_enum_is_method::generate_enum_is_method,
             generate_enum_projection_method::generate_enum_as_method,
diff --git a/crates/ide_assists/src/tests/generated.rs b/crates/ide_assists/src/tests/generated.rs
index 3f77edd8d..736027ff0 100644
--- a/crates/ide_assists/src/tests/generated.rs
+++ b/crates/ide_assists/src/tests/generated.rs
@@ -722,6 +722,35 @@ impl<T: Clone> Ctx<T> {
 }
 
 #[test]
+fn doctest_generate_is_empty_from_len() {
+    check_doc_test(
+        "generate_is_empty_from_len",
+        r#####"
+struct MyStruct { data: Vec<String> }
+
+impl MyStruct {
+    p$0ub fn len(&self) -> usize {
+        self.data.len()
+    }
+}
+"#####,
+        r#####"
+struct MyStruct { data: Vec<String> }
+
+impl MyStruct {
+    pub fn len(&self) -> usize {
+        self.data.len()
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+}
+"#####,
+    )
+}
+
+#[test]
 fn doctest_generate_new() {
     check_doc_test(
         "generate_new",
diff --git a/crates/ide_completion/Cargo.toml b/crates/ide_completion/Cargo.toml
index 585ecca50..6bd8a5500 100644
--- a/crates/ide_completion/Cargo.toml
+++ b/crates/ide_completion/Cargo.toml
@@ -10,7 +10,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = "1.1"
+cov-mark = { version = "1.1", features = ["thread-local"] }
 itertools = "0.10.0"
 log = "0.4.8"
 rustc-hash = "1.1.0"
diff --git a/crates/ide_completion/src/completions/pattern.rs b/crates/ide_completion/src/completions/pattern.rs
index 9282c3827..46cef58f0 100644
--- a/crates/ide_completion/src/completions/pattern.rs
+++ b/crates/ide_completion/src/completions/pattern.rs
@@ -11,10 +11,13 @@ pub(crate) fn complete_pattern(acc: &mut Completions, ctx: &CompletionContext) {
         return;
     }
 
-    if let Some(ty) = &ctx.expected_type {
-        super::complete_enum_variants(acc, ctx, ty, |acc, ctx, variant, path| {
-            acc.add_qualified_variant_pat(ctx, variant, path)
-        });
+    if !ctx.is_irrefutable_pat_binding {
+        if let Some(ty) = ctx.expected_type.as_ref() {
+            super::complete_enum_variants(acc, ctx, ty, |acc, ctx, variant, path| {
+                acc.add_qualified_variant_pat(ctx, variant, path.clone());
+                acc.add_qualified_enum_variant(ctx, variant, path);
+            });
+        }
     }
 
     // FIXME: ideally, we should look at the type we are matching against and
@@ -85,7 +88,7 @@ static FOO: E = E::X;
 struct Bar { f: u32 }
 
 fn foo() {
-   match E::X { $0 }
+   match E::X { a$0 }
 }
 "#,
             expect![[r#"
@@ -106,10 +109,11 @@ macro_rules! m { ($e:expr) => { $e } }
 enum E { X }
 
 fn foo() {
-   m!(match E::X { $0 })
+   m!(match E::X { a$0 })
 }
 "#,
             expect![[r#"
+                ev E::X  ()
                 en E
                 ma m!(…) macro_rules! m
             "#]],
@@ -129,7 +133,7 @@ static FOO: E = E::X;
 struct Bar { f: u32 }
 
 fn foo() {
-   let $0
+   let a$0
 }
 "#,
             expect![[r#"
@@ -147,7 +151,7 @@ enum E { X }
 static FOO: E = E::X;
 struct Bar { f: u32 }
 
-fn foo($0) {
+fn foo(a$0) {
 }
 "#,
             expect![[r#"
@@ -163,7 +167,7 @@ fn foo($0) {
 struct Bar { f: u32 }
 
 fn foo() {
-   let $0
+   let a$0
 }
 "#,
             expect![[r#"
@@ -179,7 +183,7 @@ fn foo() {
 struct Foo { bar: String, baz: String }
 struct Bar(String, String);
 struct Baz;
-fn outer($0) {}
+fn outer(a$0) {}
 "#,
             expect![[r#"
                 bn Foo Foo { bar$1, baz$2 }: Foo$0
@@ -196,7 +200,7 @@ struct Foo { bar: String, baz: String }
 struct Bar(String, String);
 struct Baz;
 fn outer() {
-    let $0
+    let a$0
 }
 "#,
             expect![[r#"
@@ -215,7 +219,7 @@ struct Bar(String, String);
 struct Baz;
 fn outer() {
     match () {
-        $0
+        a$0
     }
 }
 "#,
@@ -239,7 +243,7 @@ use foo::*;
 
 fn outer() {
     match () {
-        $0
+        a$0
     }
 }
 "#,
@@ -258,7 +262,7 @@ fn outer() {
 struct Foo(i32);
 fn main() {
     match Foo(92) {
-        $0(92) => (),
+        a$0(92) => (),
     }
 }
 "#,
@@ -281,7 +285,7 @@ struct Foo(i32);
 impl Foo {
     fn foo() {
         match () {
-            $0
+            a$0
         }
     }
 }
@@ -314,4 +318,86 @@ impl Foo {
             "#]],
         )
     }
+
+    #[test]
+    fn completes_enum_variant_matcharm() {
+        check(
+            r#"
+enum Foo { Bar, Baz, Quux }
+
+fn main() {
+    let foo = Foo::Quux;
+    match foo { Qu$0 }
+}
+"#,
+            expect![[r#"
+                ev Foo::Bar  ()
+                ev Foo::Baz  ()
+                ev Foo::Quux ()
+                en Foo
+            "#]],
+        )
+    }
+
+    #[test]
+    fn completes_enum_variant_matcharm_ref() {
+        check(
+            r#"
+enum Foo { Bar, Baz, Quux }
+
+fn main() {
+    let foo = Foo::Quux;
+    match &foo { Qu$0 }
+}
+"#,
+            expect![[r#"
+                ev Foo::Bar  ()
+                ev Foo::Baz  ()
+                ev Foo::Quux ()
+                en Foo
+            "#]],
+        )
+    }
+
+    #[test]
+    fn completes_enum_variant_iflet() {
+        check(
+            r#"
+enum Foo { Bar, Baz, Quux }
+
+fn main() {
+    let foo = Foo::Quux;
+    if let Qu$0 = foo { }
+}
+"#,
+            expect![[r#"
+                ev Foo::Bar  ()
+                ev Foo::Baz  ()
+                ev Foo::Quux ()
+                en Foo
+            "#]],
+        )
+    }
+
+    #[test]
+    fn completes_enum_variant_impl() {
+        check(
+            r#"
+enum Foo { Bar, Baz, Quux }
+impl Foo {
+    fn foo() { match Foo::Bar { Q$0 } }
+}
+"#,
+            expect![[r#"
+                ev Self::Bar  ()
+                ev Self::Baz  ()
+                ev Self::Quux ()
+                ev Foo::Bar   ()
+                ev Foo::Baz   ()
+                ev Foo::Quux  ()
+                sp Self
+                en Foo
+            "#]],
+        )
+    }
 }
diff --git a/crates/ide_completion/src/completions/unqualified_path.rs b/crates/ide_completion/src/completions/unqualified_path.rs
index 044dfd160..5ef80f6a7 100644
--- a/crates/ide_completion/src/completions/unqualified_path.rs
+++ b/crates/ide_completion/src/completions/unqualified_path.rs
@@ -6,7 +6,7 @@ use syntax::AstNode;
 use crate::{CompletionContext, Completions};
 
 pub(crate) fn complete_unqualified_path(acc: &mut Completions, ctx: &CompletionContext) {
-    if !(ctx.is_trivial_path || ctx.is_pat_binding_or_const) {
+    if !ctx.is_trivial_path {
         return;
     }
     if ctx.record_lit_syntax.is_some()
@@ -23,10 +23,6 @@ pub(crate) fn complete_unqualified_path(acc: &mut Completions, ctx: &CompletionC
         });
     }
 
-    if ctx.is_pat_binding_or_const {
-        return;
-    }
-
     ctx.scope.process_all_names(&mut |name, res| {
         if let ScopeDef::GenericParam(hir::GenericParam::LifetimeParam(_)) = res {
             cov_mark::hit!(skip_lifetime_completion);
@@ -609,66 +605,6 @@ fn main() { $0 }
     }
 
     #[test]
-    fn completes_enum_variant_matcharm() {
-        check(
-            r#"
-enum Foo { Bar, Baz, Quux }
-
-fn main() {
-    let foo = Foo::Quux;
-    match foo { Qu$0 }
-}
-"#,
-            expect![[r#"
-                ev Foo::Bar  ()
-                ev Foo::Baz  ()
-                ev Foo::Quux ()
-                en Foo
-            "#]],
-        )
-    }
-
-    #[test]
-    fn completes_enum_variant_matcharm_ref() {
-        check(
-            r#"
-enum Foo { Bar, Baz, Quux }
-
-fn main() {
-    let foo = Foo::Quux;
-    match &foo { Qu$0 }
-}
-"#,
-            expect![[r#"
-                ev Foo::Bar  ()
-                ev Foo::Baz  ()
-                ev Foo::Quux ()
-                en Foo
-            "#]],
-        )
-    }
-
-    #[test]
-    fn completes_enum_variant_iflet() {
-        check(
-            r#"
-enum Foo { Bar, Baz, Quux }
-
-fn main() {
-    let foo = Foo::Quux;
-    if let Qu$0 = foo { }
-}
-"#,
-            expect![[r#"
-                ev Foo::Bar  ()
-                ev Foo::Baz  ()
-                ev Foo::Quux ()
-                en Foo
-            "#]],
-        )
-    }
-
-    #[test]
     fn completes_enum_variant_basic_expr() {
         check(
             r#"
@@ -701,28 +637,6 @@ fn f() -> m::E { V$0 }
     }
 
     #[test]
-    fn completes_enum_variant_impl() {
-        check(
-            r#"
-enum Foo { Bar, Baz, Quux }
-impl Foo {
-    fn foo() { match Foo::Bar { Q$0 } }
-}
-"#,
-            expect![[r#"
-                ev Self::Bar  ()
-                ev Self::Baz  ()
-                ev Self::Quux ()
-                ev Foo::Bar   ()
-                ev Foo::Baz   ()
-                ev Foo::Quux  ()
-                sp Self
-                en Foo
-            "#]],
-        )
-    }
-
-    #[test]
     fn dont_complete_attr() {
         check(
             r#"
diff --git a/crates/ide_completion/src/context.rs b/crates/ide_completion/src/context.rs
index 89e9bda78..e6cc6329c 100644
--- a/crates/ide_completion/src/context.rs
+++ b/crates/ide_completion/src/context.rs
@@ -350,7 +350,6 @@ impl<'a> CompletionContext<'a> {
                         },
                         ast::IdentPat(it) => {
                             cov_mark::hit!(expected_type_if_let_with_leading_char);
-                            cov_mark::hit!(expected_type_if_let_without_leading_char);
                             cov_mark::hit!(expected_type_match_arm_with_leading_char);
                             let ty = self.sema.type_of_pat(&ast::Pat::from(it));
 
@@ -748,7 +747,6 @@ fn foo() {
 
     #[test]
     fn expected_type_if_let_without_leading_char() {
-        cov_mark::check!(expected_type_if_let_without_leading_char);
         check_expected_type_and_name(
             r#"
 enum Foo { Bar, Baz, Quux }
diff --git a/crates/ide_completion/src/render.rs b/crates/ide_completion/src/render.rs
index 670563e50..2514dda7c 100644
--- a/crates/ide_completion/src/render.rs
+++ b/crates/ide_completion/src/render.rs
@@ -928,6 +928,66 @@ fn f(foo: &Foo) { f(foo, w$0) }
     }
 
     #[test]
+    fn score_fn_type_and_name_match() {
+        check_relevance(
+            r#"
+struct A { bar: u8 }
+fn baz() -> u8 { 0 }
+fn bar() -> u8 { 0 }
+fn f() { A { bar: b$0 }; }
+"#,
+            expect![[r#"
+                fn baz() [type]
+                st A []
+                fn bar() [type+name]
+                fn f() []
+            "#]],
+        );
+    }
+
+    #[test]
+    fn score_method_type_and_name_match() {
+        check_relevance(
+            r#"
+fn baz(aaa: u32){}
+struct Foo;
+impl Foo {
+fn aaa(&self) -> u32 { 0 }
+fn bbb(&self) -> u32 { 0 }
+fn ccc(&self) -> u64 { 0 }
+}
+fn f() {
+    baz(Foo.$0
+}
+"#,
+            expect![[r#"
+                me aaa() [type+name]
+                me bbb() [type]
+                me ccc() []
+            "#]],
+        );
+    }
+
+    #[test]
+    fn score_method_name_match_only() {
+        check_relevance(
+            r#"
+fn baz(aaa: u32){}
+struct Foo;
+impl Foo {
+fn aaa(&self) -> u64 { 0 }
+}
+fn f() {
+    baz(Foo.$0
+}
+"#,
+            expect![[r#"
+                me aaa() [name]
+            "#]],
+        );
+    }
+
+    #[test]
     fn suggest_ref_mut() {
         cov_mark::check!(suggest_ref);
         check(
diff --git a/crates/ide_completion/src/render/function.rs b/crates/ide_completion/src/render/function.rs
index f4dabe3d1..47e26a5d8 100644
--- a/crates/ide_completion/src/render/function.rs
+++ b/crates/ide_completion/src/render/function.rs
@@ -5,7 +5,7 @@ use ide_db::SymbolKind;
 use syntax::ast::Fn;
 
 use crate::{
-    item::{CompletionItem, CompletionItemKind, CompletionKind, ImportEdit},
+    item::{CompletionItem, CompletionItemKind, CompletionKind, CompletionRelevance, ImportEdit},
     render::{builder_ext::Params, RenderContext},
 };
 
@@ -55,6 +55,21 @@ impl<'a> FunctionRender<'a> {
             .add_call_parens(self.ctx.completion, self.name, params)
             .add_import(import_to_add);
 
+        let mut relevance = CompletionRelevance::default();
+        if let Some(expected_type) = &self.ctx.completion.expected_type {
+            let ret_ty = self.func.ret_type(self.ctx.db());
+
+            // We don't ever consider a function which returns unit type to be an
+            // exact type match, since nearly always this is not meaningful to the
+            // user.
+            relevance.exact_type_match = &ret_ty == expected_type && !ret_ty.is_unit();
+        }
+        if let Some(expected_name) = &self.ctx.completion.expected_name {
+            relevance.exact_name_match =
+                expected_name == &self.func.name(self.ctx.db()).to_string();
+        }
+        item.set_relevance(relevance);
+
         item.build()
     }
 
diff --git a/crates/ide_completion/src/render/pattern.rs b/crates/ide_completion/src/render/pattern.rs
index ca2926125..b4e80f424 100644
--- a/crates/ide_completion/src/render/pattern.rs
+++ b/crates/ide_completion/src/render/pattern.rs
@@ -6,24 +6,6 @@ use itertools::Itertools;
 
 use crate::{item::CompletionKind, render::RenderContext, CompletionItem, CompletionItemKind};
 
-fn visible_fields(
-    ctx: &RenderContext<'_>,
-    fields: &[hir::Field],
-    item: impl HasAttrs,
-) -> Option<(Vec<hir::Field>, bool)> {
-    let module = ctx.completion.scope.module()?;
-    let n_fields = fields.len();
-    let fields = fields
-        .into_iter()
-        .filter(|field| field.is_visible_from(ctx.db(), module))
-        .copied()
-        .collect::<Vec<_>>();
-
-    let fields_omitted =
-        n_fields - fields.len() > 0 || item.attrs(ctx.db()).by_key("non_exhaustive").exists();
-    Some((fields, fields_omitted))
-}
-
 pub(crate) fn render_struct_pat(
     ctx: RenderContext<'_>,
     strukt: hir::Struct,
@@ -148,3 +130,21 @@ fn render_tuple_as_pat(fields: &[hir::Field], name: &str, fields_omitted: bool)
         name = name
     )
 }
+
+fn visible_fields(
+    ctx: &RenderContext<'_>,
+    fields: &[hir::Field],
+    item: impl HasAttrs,
+) -> Option<(Vec<hir::Field>, bool)> {
+    let module = ctx.completion.scope.module()?;
+    let n_fields = fields.len();
+    let fields = fields
+        .into_iter()
+        .filter(|field| field.is_visible_from(ctx.db(), module))
+        .copied()
+        .collect::<Vec<_>>();
+
+    let fields_omitted =
+        n_fields - fields.len() > 0 || item.attrs(ctx.db()).by_key("non_exhaustive").exists();
+    Some((fields, fields_omitted))
+}
diff --git a/crates/ide_db/Cargo.toml b/crates/ide_db/Cargo.toml
index 1f7a90d20..6229996ec 100644
--- a/crates/ide_db/Cargo.toml
+++ b/crates/ide_db/Cargo.toml
@@ -10,7 +10,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = "1.1"
+cov-mark = { version = "1.1", features = ["thread-local"] }
 log = "0.4.8"
 rayon = "1.5.0"
 fst = { version = "0.4", default-features = false }
diff --git a/crates/ide_ssr/Cargo.toml b/crates/ide_ssr/Cargo.toml
index 8c31df13a..5d2221ebc 100644
--- a/crates/ide_ssr/Cargo.toml
+++ b/crates/ide_ssr/Cargo.toml
@@ -11,7 +11,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = "1.1"
+cov-mark = { version = "1.1", features = ["thread-local"] }
 rustc-hash = "1.1.0"
 itertools = "0.10.0"
 
diff --git a/crates/mbe/Cargo.toml b/crates/mbe/Cargo.toml
index 139214207..8856787c0 100644
--- a/crates/mbe/Cargo.toml
+++ b/crates/mbe/Cargo.toml
@@ -10,7 +10,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = "1.1"
+cov-mark = { version = "1.1", features = ["thread-local"] }
 rustc-hash = "1.1.0"
 smallvec = "1.2.0"
 log = "0.4.8"
diff --git a/crates/proc_macro_api/src/lib.rs b/crates/proc_macro_api/src/lib.rs
index 941d0fe9e..2dd2a8541 100644
--- a/crates/proc_macro_api/src/lib.rs
+++ b/crates/proc_macro_api/src/lib.rs
@@ -23,6 +23,7 @@ use tt::{SmolStr, Subtree};
 use crate::process::{ProcMacroProcessSrv, ProcMacroProcessThread};
 
 pub use rpc::{ExpansionResult, ExpansionTask, ListMacrosResult, ListMacrosTask, ProcMacroKind};
+pub use version::{read_dylib_info, RustCInfo};
 
 #[derive(Debug, Clone)]
 struct ProcMacroProcessExpander {
@@ -76,7 +77,7 @@ impl ProcMacroClient {
     }
 
     pub fn by_dylib_path(&self, dylib_path: &Path) -> Vec<ProcMacro> {
-        match version::read_info(dylib_path) {
+        match version::read_dylib_info(dylib_path) {
             Ok(info) => {
                 if info.version.0 < 1 || info.version.1 < 47 {
                     eprintln!("proc-macro {} built by {:#?} is not supported by Rust Analyzer, please update your rust version.", dylib_path.to_string_lossy(), info);
diff --git a/crates/proc_macro_api/src/version.rs b/crates/proc_macro_api/src/version.rs
index b903658fb..dcf8fae8f 100644
--- a/crates/proc_macro_api/src/version.rs
+++ b/crates/proc_macro_api/src/version.rs
@@ -11,14 +11,15 @@ use object::read::{File as BinaryFile, Object, ObjectSection};
 use snap::read::FrameDecoder as SnapDecoder;
 
 #[derive(Debug)]
-pub(crate) struct RustCInfo {
-    pub(crate) version: (usize, usize, usize),
-    pub(crate) channel: String,
-    pub(crate) commit: String,
-    pub(crate) date: String,
+pub struct RustCInfo {
+    pub version: (usize, usize, usize),
+    pub channel: String,
+    pub commit: String,
+    pub date: String,
 }
 
-pub(crate) fn read_info(dylib_path: &Path) -> io::Result<RustCInfo> {
+/// Read rustc dylib information
+pub fn read_dylib_info(dylib_path: &Path) -> io::Result<RustCInfo> {
     macro_rules! err {
         ($e:literal) => {
             io::Error::new(io::ErrorKind::InvalidData, $e)
diff --git a/crates/proc_macro_srv/src/tests/mod.rs b/crates/proc_macro_srv/src/tests/mod.rs
index fd54f8dfd..b4ab4c077 100644
--- a/crates/proc_macro_srv/src/tests/mod.rs
+++ b/crates/proc_macro_srv/src/tests/mod.rs
@@ -56,3 +56,10 @@ DummyTrait [CustomDerive]"#,
         &res
     );
 }
+
+#[test]
+fn test_version_check() {
+    let path = fixtures::dylib_path("proc_macro_test", "0.0.0");
+    let info = proc_macro_api::read_dylib_info(&path).unwrap();
+    assert!(info.version.1 >= 50);
+}
diff --git a/crates/proc_macro_srv/src/tests/utils.rs b/crates/proc_macro_srv/src/tests/utils.rs
index 0484c3af4..f15381f0f 100644
--- a/crates/proc_macro_srv/src/tests/utils.rs
+++ b/crates/proc_macro_srv/src/tests/utils.rs
@@ -6,7 +6,7 @@ use proc_macro_api::ListMacrosTask;
 use std::str::FromStr;
 use test_utils::assert_eq_text;
 
-mod fixtures {
+pub mod fixtures {
     use cargo_metadata::Message;
     use std::path::PathBuf;
     use std::process::Command;
diff --git a/crates/rust-analyzer/src/config.rs b/crates/rust-analyzer/src/config.rs
index 8af7871ac..8f541976e 100644
--- a/crates/rust-analyzer/src/config.rs
+++ b/crates/rust-analyzer/src/config.rs
@@ -172,7 +172,7 @@ config_data! {
         notifications_cargoTomlNotFound: bool      = "true",
 
         /// Enable support for procedural macros, implies `#rust-analyzer.cargo.runBuildScripts#`.
-        procMacro_enable: bool                     = "false",
+        procMacro_enable: bool                     = "true",
         /// Internal config, path to proc-macro server executable (typically,
         /// this is rust-analyzer itself, but we override this in tests).
         procMacro_server: Option<PathBuf>          = "null",
diff --git a/crates/syntax/Cargo.toml b/crates/syntax/Cargo.toml
index 05fca5dc4..c0fd894b0 100644
--- a/crates/syntax/Cargo.toml
+++ b/crates/syntax/Cargo.toml
@@ -11,7 +11,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-cov-mark = "1.1"
+cov-mark = { version = "1.1", features = ["thread-local"] }
 itertools = "0.10.0"
 rowan = "0.12.2"
 rustc_lexer = { version = "710.0.0", package = "rustc-ap-rustc_lexer" }
diff --git a/docs/user/generated_config.adoc b/docs/user/generated_config.adoc
index 042ba2d54..c2521289c 100644
--- a/docs/user/generated_config.adoc
+++ b/docs/user/generated_config.adoc
@@ -276,7 +276,7 @@ Number of syntax trees rust-analyzer keeps in memory. Defaults to 128.
 --
 Whether to show `can't find Cargo.toml` error message.
 --
-[[rust-analyzer.procMacro.enable]]rust-analyzer.procMacro.enable (default: `false`)::
+[[rust-analyzer.procMacro.enable]]rust-analyzer.procMacro.enable (default: `true`)::
 +
 --
 Enable support for procedural macros, implies `#rust-analyzer.cargo.runBuildScripts#`.
diff --git a/editors/code/package.json b/editors/code/package.json
index 923e9b35a..a2ed9b2d5 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -690,7 +690,7 @@
                 },
                 "rust-analyzer.procMacro.enable": {
                     "markdownDescription": "Enable support for procedural macros, implies `#rust-analyzer.cargo.runBuildScripts#`.",
-                    "default": false,
+                    "default": true,
                     "type": "boolean"
                 },
                 "rust-analyzer.procMacro.server": {
diff --git a/xtask/src/metrics.rs b/xtask/src/metrics.rs
index 72de92c64..3d8d7589b 100644
--- a/xtask/src/metrics.rs
+++ b/xtask/src/metrics.rs
@@ -26,7 +26,7 @@ impl flags::Metrics {
         }
         {
             let _d = pushd("./target/rustc-perf")?;
-            cmd!("git reset --hard 1d9288b0da7febf2599917da1b57dc241a1af033").run()?;
+            cmd!("git reset --hard c52ee623e231e7690a93be88d943016968c1036b").run()?;
         }
 
         let _env = pushenv("RA_METRICS", "1");
@@ -35,6 +35,7 @@ impl flags::Metrics {
         metrics.measure_analysis_stats_self()?;
         metrics.measure_analysis_stats("ripgrep")?;
         metrics.measure_analysis_stats("webrender")?;
+        metrics.measure_analysis_stats("diesel/diesel")?;
 
         if !self.dry_run {
             let _d = pushd("target")?;