20 files changed, 320 insertions, 90 deletions
diff --git a/Cargo.lock b/Cargo.lock
index 759895695..fd04ec3c5 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -168,9 +168,9 @@ checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 [[package]]
 name = "chalk-derive"
-version = "0.43.0"
+version = "0.45.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e2d9e0c8adcced1ab0fea5cb8a38647922893d5b495e363e1814299fd380469b"
+checksum = "ec7dacf94958d1a930b95d049d9443860859af59eadc77849392093eb577bcee"
 dependencies = [
 "proc-macro2",
 "quote",
@@ -180,19 +180,20 @@ dependencies = [
 [[package]]
 name = "chalk-ir"
-version = "0.43.0"
+version = "0.45.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c5218266a5709bc4943de997e64d3fab41c9e9f68efd54a898de53135e987bd3"
+checksum = "a1a5b38ede247def17da87f4badb62396a5753db6048e2011d3089d8b3796c67"
 dependencies = [
+ "bitflags",
 "chalk-derive",
 "lazy_static",
 ]
 [[package]]
 name = "chalk-recursive"
-version = "0.43.0"
+version = "0.45.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ed8f34f13fd4f30251f9f6f1dc56f80363201390ecbcac2fdfc8e33036cd9c4a"
+checksum = "7a18db146d7a023edc20ad094e8c2284451f7888719645004979617d1f17c041"
 dependencies = [
 "chalk-derive",
 "chalk-ir",
@@ -203,9 +204,9 @@ dependencies = [
 [[package]]
 name = "chalk-solve"
-version = "0.43.0"
+version = "0.45.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "379c9f584488346044709d4c638c38d61a06fe593d4de2ac5f15fd2b0ba4cd9d"
+checksum = "7f73e0de04a0f394e47ed8118e00541bcf681d7c3c2ef500fa743eb4cf3a4850"
 dependencies = [
 "chalk-derive",
 "chalk-ir",
@@ -507,9 +508,9 @@ checksum = "d7afe4a420e3fe79967a00898cc1f4db7c8a49a9333a29f8a4bd76a253d5cd04"
 [[package]]
 name = "heck"
-version = "0.3.1"
+version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "20564e78d53d2bb135c343b3f47714a56af2061f1c928fdb541dc7b9fdd94205"
+checksum = "87cbf45460356b7deeb5e3415b5563308c0a9b057c85e12b06ad551f98d0a6ac"
 dependencies = [
 "unicode-segmentation",
 ]
@@ -1074,9 +1075,9 @@ dependencies = [
 [[package]]
 name = "parking_lot_core"
-version = "0.8.1"
+version = "0.8.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d7c6d9b8427445284a09c55be860a15855ab580a417ccad9da88f5a06787ced0"
+checksum = "9ccb628cad4f84851442432c60ad8e1f607e29752d0bf072cbd0baf28aa34272"
 dependencies = [
 "cfg-if 1.0.0",
 "instant",
@@ -1377,9 +1378,9 @@ dependencies = [
 [[package]]
 name = "rustc-ap-rustc_lexer"
-version = "691.0.0"
+version = "695.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "44bc89d9ca7a78fb82e103b389362c55f03800745f8ba14e068b805cfaf783ec"
+checksum = "390bad134705b0bff02cd9541ac66df751a91c3cc734c3369cd6151ca269caed"
 dependencies = [
 "unicode-xid",
 ]
@@ -1837,9 +1838,9 @@ checksum = "56dee185309b50d1f11bfedef0fe6d036842e3fb77413abef29f8f8d1c5d4c1c"
 [[package]]
 name = "ungrammar"
-version = "1.4.0"
+version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "68951379f3ced25754472ca5addbf74d7dab58c9818f49290a3d8caa3ab44fb7"
+checksum = "c11bffada52edc8f2a56160b286ea4640acf90ffcb21bded361ccb8ed43a1457"
 [[package]]
 name = "unicase"
diff --git a/crates/completion/src/completions/qualified_path.rs b/crates/completion/src/completions/qualified_path.rs
index 1300f00b2..882c4dcbc 100644
--- a/crates/completion/src/completions/qualified_path.rs
+++ b/crates/completion/src/completions/qualified_path.rs
@@ -118,6 +118,12 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
                    _ => return,
                };
+                if let Some(Adt::Enum(e)) = ty.as_adt() {
+                    for variant in e.variants(ctx.db) {
+                        acc.add_enum_variant(ctx, variant, None);
+                    }
+                }
                let traits_in_scope = ctx.scope.traits_in_scope();
                let mut seen = FxHashSet::default();
                ty.iterate_path_candidates(ctx.db, krate, &traits_in_scope, None, |_ty, item| {
@@ -752,4 +758,27 @@ fn main() {
            "#]],
        );
    }
+    #[test]
+    fn completes_self_enum() {
+        check(
+            r#"
+enum Foo {
+    Bar,
+    Baz,
+}
+impl Foo {
+    fn foo(self) {
+        Self::<|>
+    }
+}
+"#,
+            expect![[r#"
+                ev Bar    ()
+                ev Baz    ()
+                me foo(…) fn foo(self)
+            "#]],
+        );
+    }
 }
diff --git a/crates/completion/src/completions/unqualified_path.rs b/crates/completion/src/completions/unqualified_path.rs
index 099ffb4d4..d09849752 100644
--- a/crates/completion/src/completions/unqualified_path.rs
+++ b/crates/completion/src/completions/unqualified_path.rs
@@ -1,5 +1,7 @@
 //! Completion of names from the current scope, e.g. locals and imported items.
+use std::iter;
 use either::Either;
 use hir::{Adt, ModPath, ModuleDef, ScopeDef, Type};
 use ide_db::helpers::insert_use::ImportScope;
@@ -50,7 +52,9 @@ pub(crate) fn complete_unqualified_path(acc: &mut Completions, ctx: &CompletionC
 }
 fn complete_enum_variants(acc: &mut Completions, ctx: &CompletionContext, ty: &Type) {
-    if let Some(Adt::Enum(enum_data)) = ty.as_adt() {
+    if let Some(Adt::Enum(enum_data)) =
+        iter::successors(Some(ty.clone()), |ty| ty.remove_ref()).last().and_then(|ty| ty.as_adt())
+    {
        let variants = enum_data.variants(ctx.db);
        let module = if let Some(module) = ctx.scope.module() {
@@ -701,6 +705,7 @@ fn main() { <|> }
            "#]],
        );
    }
    #[test]
    fn completes_enum_variant_matcharm() {
        check(
@@ -722,6 +727,26 @@ fn main() {
    }
    #[test]
+    fn completes_enum_variant_matcharm_ref() {
+        check(
+            r#"
+enum Foo { Bar, Baz, Quux }
+fn main() {
+    let foo = Foo::Quux;
+    match &foo { Qu<|> }
+}
+"#,
+            expect![[r#"
+                ev Foo::Bar  ()
+                ev Foo::Baz  ()
+                ev Foo::Quux ()
+                en Foo
+            "#]],
+        )
+    }
+    #[test]
    fn completes_enum_variant_iflet() {
        check(
            r#"
diff --git a/crates/hir_def/src/body/lower.rs b/crates/hir_def/src/body/lower.rs
index 0f404be1b..978c3a324 100644
--- a/crates/hir_def/src/body/lower.rs
+++ b/crates/hir_def/src/body/lower.rs
@@ -933,7 +933,9 @@ impl ExprCollector<'_> {
                Pat::Box { inner }
            }
            // FIXME: implement
-            ast::Pat::RangePat(_) | ast::Pat::MacroPat(_) => Pat::Missing,
+            ast::Pat::RangePat(_) | ast::Pat::MacroPat(_) | ast::Pat::ConstBlockPat(_) => {
+                Pat::Missing
+            }
        };
        let ptr = AstPtr::new(&pat);
        self.alloc_pat(pattern, Either::Left(ptr))
diff --git a/crates/hir_ty/Cargo.toml b/crates/hir_ty/Cargo.toml
index 289e812fe..965c1780a 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 = "0.43", default-features = false }
+chalk-solve = { version = "0.45", default-features = false }
-chalk-ir = "0.43"
+chalk-ir = "0.45"
-chalk-recursive = "0.43"
+chalk-recursive = "0.45"
 stdx = { path = "../stdx", version = "0.0.0" }
 hir_def = { path = "../hir_def", version = "0.0.0" }
diff --git a/crates/hir_ty/src/traits/chalk.rs b/crates/hir_ty/src/traits/chalk.rs
index 69eae6f79..2196af677 100644
--- a/crates/hir_ty/src/traits/chalk.rs
+++ b/crates/hir_ty/src/traits/chalk.rs
@@ -56,8 +56,13 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
    fn adt_datum(&self, struct_id: AdtId) -> Arc<StructDatum> {
        self.db.struct_datum(self.krate, struct_id)
    }
-    fn adt_repr(&self, _struct_id: AdtId) -> rust_ir::AdtRepr {
+    fn adt_repr(&self, _struct_id: AdtId) -> Arc<rust_ir::AdtRepr<Interner>> {
-        rust_ir::AdtRepr { repr_c: false, repr_packed: false }
+        // FIXME: keep track of these
+        Arc::new(rust_ir::AdtRepr { c: false, packed: false, int: None })
+    }
+    fn discriminant_type(&self, _ty: chalk_ir::Ty<Interner>) -> chalk_ir::Ty<Interner> {
+        // FIXME: keep track of this
+        chalk_ir::TyKind::Scalar(chalk_ir::Scalar::Uint(chalk_ir::UintTy::U32)).intern(&Interner)
    }
    fn impl_datum(&self, impl_id: ImplId) -> Arc<ImplDatum> {
        self.db.impl_datum(self.krate, impl_id)
@@ -457,6 +462,7 @@ fn well_known_trait_from_lang_attr(name: &str) -> Option<WellKnownTrait> {
        "fn" => WellKnownTrait::Fn,
        "unsize" => WellKnownTrait::Unsize,
        "coerce_unsized" => WellKnownTrait::CoerceUnsized,
+        "discriminant_kind" => WellKnownTrait::DiscriminantKind,
        _ => return None,
    })
 }
@@ -473,6 +479,7 @@ fn lang_attr_from_well_known_trait(attr: WellKnownTrait) -> &'static str {
        WellKnownTrait::Unsize => "unsize",
        WellKnownTrait::Unpin => "unpin",
        WellKnownTrait::CoerceUnsized => "coerce_unsized",
+        WellKnownTrait::DiscriminantKind => "discriminant_kind",
    }
 }
diff --git a/crates/parser/src/grammar/expressions/atom.rs b/crates/parser/src/grammar/expressions/atom.rs
index e897d5a52..c7a3556a7 100644
--- a/crates/parser/src/grammar/expressions/atom.rs
+++ b/crates/parser/src/grammar/expressions/atom.rs
@@ -46,6 +46,7 @@ pub(super) const ATOM_EXPR_FIRST: TokenSet =
        T![continue],
        T![async],
        T![try],
+        T![const],
        T![loop],
        T![for],
        LIFETIME_IDENT,
@@ -115,6 +116,14 @@ pub(super) fn atom_expr(p: &mut Parser, r: Restrictions) -> Option<(CompletedMar
            block_expr(p);
            m.complete(p, EFFECT_EXPR)
        }
+        // test const_block
+        // fn f() { const { } }
+        T![const] if la == T!['{'] => {
+            let m = p.start();
+            p.bump(T![const]);
+            block_expr(p);
+            m.complete(p, EFFECT_EXPR)
+        }
        T!['{'] => {
            // test for_range_from
            // fn foo() {
diff --git a/crates/parser/src/grammar/items.rs b/crates/parser/src/grammar/items.rs
index 8999829b4..72b73f891 100644
--- a/crates/parser/src/grammar/items.rs
+++ b/crates/parser/src/grammar/items.rs
@@ -96,7 +96,10 @@ pub(super) fn maybe_item(p: &mut Parser, m: Marker) -> Result<(), Marker> {
    let mut has_mods = false;
    // modifiers
-    has_mods |= p.eat(T![const]);
+    if p.at(T![const]) && p.nth(1) != T!['{'] {
+        p.eat(T![const]);
+        has_mods = true;
+    }
    // test_err async_without_semicolon
    // fn foo() { let _ = async {} }
@@ -167,7 +170,7 @@ pub(super) fn maybe_item(p: &mut Parser, m: Marker) -> Result<(), Marker> {
            m.complete(p, TRAIT);
        }
-        T![const] => {
+        T![const] if p.nth(1) != T!['{'] => {
            consts::konst(p, m);
        }
diff --git a/crates/parser/src/grammar/patterns.rs b/crates/parser/src/grammar/patterns.rs
index 7e7f73dee..b53d5749f 100644
--- a/crates/parser/src/grammar/patterns.rs
+++ b/crates/parser/src/grammar/patterns.rs
@@ -89,6 +89,7 @@ fn atom_pat(p: &mut Parser, recovery_set: TokenSet) -> Option<CompletedMarker> {
    let m = match p.nth(0) {
        T![box] => box_pat(p),
        T![ref] | T![mut] => ident_pat(p, true),
+        T![const] => const_block_pat(p),
        IDENT => match p.nth(1) {
            // Checks the token after an IDENT to see if a pattern is a path (Struct { .. }) or macro
            // (T![x]).
@@ -386,3 +387,16 @@ fn box_pat(p: &mut Parser) -> CompletedMarker {
    pattern_single(p);
    m.complete(p, BOX_PAT)
 }
+// test const_block_pat
+// fn main() {
+//     let const { 15 } = ();
+//     let const { foo(); bar() } = ();
+// }
+fn const_block_pat(p: &mut Parser) -> CompletedMarker {
+    assert!(p.at(T![const]));
+    let m = p.start();
+    p.bump(T![const]);
+    expressions::block_expr(p);
+    m.complete(p, CONST_BLOCK_PAT)
+}
diff --git a/crates/parser/src/syntax_kind/generated.rs b/crates/parser/src/syntax_kind/generated.rs
index 980aa5979..f69e71bdb 100644
--- a/crates/parser/src/syntax_kind/generated.rs
+++ b/crates/parser/src/syntax_kind/generated.rs
@@ -170,6 +170,7 @@ pub enum SyntaxKind {
    RANGE_PAT,
    LITERAL_PAT,
    MACRO_PAT,
+    CONST_BLOCK_PAT,
    TUPLE_EXPR,
    ARRAY_EXPR,
    PAREN_EXPR,
diff --git a/crates/rust-analyzer/src/handlers.rs b/crates/rust-analyzer/src/handlers.rs
index 66f8bee99..55bc2bcec 100644
--- a/crates/rust-analyzer/src/handlers.rs
+++ b/crates/rust-analyzer/src/handlers.rs
@@ -5,11 +5,13 @@
 use std::{
    io::Write as _,
    process::{self, Stdio},
+    sync::Arc,
 };
 use ide::{
-    CompletionResolveCapability, FileId, FilePosition, FileRange, HoverAction, HoverGotoTypeData,
+    AssistConfig, CompletionResolveCapability, FileId, FilePosition, FileRange, HoverAction,
-    NavigationTarget, Query, RangeInfo, Runnable, RunnableKind, SearchScope, SymbolKind, TextEdit,
+    HoverGotoTypeData, LineIndex, NavigationTarget, Query, RangeInfo, Runnable, RunnableKind,
+    SearchScope, SymbolKind, TextEdit,
 };
 use itertools::Itertools;
 use lsp_server::ErrorCode;
@@ -865,58 +867,8 @@ pub(crate) fn handle_formatting(
    }
 }
-fn handle_fixes(
-    snap: &GlobalStateSnapshot,
-    params: &lsp_types::CodeActionParams,
-    res: &mut Vec<lsp_ext::CodeAction>,
-) -> Result<()> {
-    let file_id = from_proto::file_id(&snap, &params.text_document.uri)?;
-    let line_index = snap.analysis.file_line_index(file_id)?;
-    let range = from_proto::text_range(&line_index, params.range);
-    match &params.context.only {
-        Some(v) => {
-            if !v.iter().any(|it| {
-                it == &lsp_types::CodeActionKind::EMPTY
-                    || it == &lsp_types::CodeActionKind::QUICKFIX
-            }) {
-                return Ok(());
-            }
-        }
-        None => {}
-    };
-    let diagnostics = snap.analysis.diagnostics(&snap.config.diagnostics, file_id)?;
-    for fix in diagnostics
-        .into_iter()
-        .filter_map(|d| d.fix)
-        .filter(|fix| fix.fix_trigger_range.intersect(range).is_some())
-    {
-        let edit = to_proto::snippet_workspace_edit(&snap, fix.source_change)?;
-        let action = lsp_ext::CodeAction {
-            title: fix.label.to_string(),
-            group: None,
-            kind: Some(CodeActionKind::QUICKFIX),
-            edit: Some(edit),
-            is_preferred: Some(false),
-            data: None,
-        };
-        res.push(action);
-    }
-    for fix in snap.check_fixes.get(&file_id).into_iter().flatten() {
-        let fix_range = from_proto::text_range(&line_index, fix.range);
-        if fix_range.intersect(range).is_none() {
-            continue;
-        }
-        res.push(fix.action.clone());
-    }
-    Ok(())
-}
 pub(crate) fn handle_code_action(
-    mut snap: GlobalStateSnapshot,
+    snap: GlobalStateSnapshot,
    params: lsp_types::CodeActionParams,
 ) -> Result<Option<Vec<lsp_ext::CodeAction>>> {
    let _p = profile::span("handle_code_action");
@@ -932,24 +884,35 @@ pub(crate) fn handle_code_action(
    let range = from_proto::text_range(&line_index, params.range);
    let frange = FileRange { file_id, range };
-    snap.config.assist.allowed = params
+    let assists_config = AssistConfig {
-        .clone()
+        allowed: params
-        .context
+            .clone()
-        .only
+            .context
-        .map(|it| it.into_iter().filter_map(from_proto::assist_kind).collect());
+            .only
+            .map(|it| it.into_iter().filter_map(from_proto::assist_kind).collect()),
+        ..snap.config.assist
+    };
    let mut res: Vec<lsp_ext::CodeAction> = Vec::new();
-    handle_fixes(&snap, &params, &mut res)?;
+    let include_quick_fixes = match &params.context.only {
+        Some(v) => v.iter().any(|it| {
+            it == &lsp_types::CodeActionKind::EMPTY || it == &lsp_types::CodeActionKind::QUICKFIX
+        }),
+        None => true,
+    };
+    if include_quick_fixes {
+        add_quick_fixes(&snap, frange, &line_index, &mut res)?;
+    }
    if snap.config.client_caps.code_action_resolve {
        for (index, assist) in
-            snap.analysis.unresolved_assists(&snap.config.assist, frange)?.into_iter().enumerate()
+            snap.analysis.unresolved_assists(&assists_config, frange)?.into_iter().enumerate()
        {
            res.push(to_proto::unresolved_code_action(&snap, params.clone(), assist, index)?);
        }
    } else {
-        for assist in snap.analysis.resolved_assists(&snap.config.assist, frange)?.into_iter() {
+        for assist in snap.analysis.resolved_assists(&assists_config, frange)?.into_iter() {
            res.push(to_proto::resolved_code_action(&snap, assist)?);
        }
    }
@@ -957,6 +920,40 @@ pub(crate) fn handle_code_action(
    Ok(Some(res))
 }
+fn add_quick_fixes(
+    snap: &GlobalStateSnapshot,
+    frange: FileRange,
+    line_index: &Arc<LineIndex>,
+    acc: &mut Vec<lsp_ext::CodeAction>,
+) -> Result<()> {
+    let diagnostics = snap.analysis.diagnostics(&snap.config.diagnostics, frange.file_id)?;
+    for fix in diagnostics
+        .into_iter()
+        .filter_map(|d| d.fix)
+        .filter(|fix| fix.fix_trigger_range.intersect(frange.range).is_some())
+    {
+        let edit = to_proto::snippet_workspace_edit(&snap, fix.source_change)?;
+        let action = lsp_ext::CodeAction {
+            title: fix.label.to_string(),
+            group: None,
+            kind: Some(CodeActionKind::QUICKFIX),
+            edit: Some(edit),
+            is_preferred: Some(false),
+            data: None,
+        };
+        acc.push(action);
+    }
+    for fix in snap.check_fixes.get(&frange.file_id).into_iter().flatten() {
+        let fix_range = from_proto::text_range(&line_index, fix.range);
+        if fix_range.intersect(frange.range).is_some() {
+            acc.push(fix.action.clone());
+        }
+    }
+    Ok(())
+}
 pub(crate) fn handle_code_action_resolve(
    mut snap: GlobalStateSnapshot,
    mut code_action: lsp_ext::CodeAction,
diff --git a/crates/syntax/Cargo.toml b/crates/syntax/Cargo.toml
index c6a6f11e1..21015591c 100644
--- a/crates/syntax/Cargo.toml
+++ b/crates/syntax/Cargo.toml
@@ -13,7 +13,7 @@ doctest = false
 [dependencies]
 itertools = "0.9.0"
 rowan = "0.10.0"
-rustc_lexer = { version = "691.0.0", package = "rustc-ap-rustc_lexer" }
+rustc_lexer = { version = "695.0.0", package = "rustc-ap-rustc_lexer" }
 rustc-hash = "1.1.0"
 arrayvec = "0.5.1"
 once_cell = "1.3.1"
diff --git a/crates/syntax/src/ast/generated/nodes.rs b/crates/syntax/src/ast/generated/nodes.rs
index 1588ba93e..c5b80bffe 100644
--- a/crates/syntax/src/ast/generated/nodes.rs
+++ b/crates/syntax/src/ast/generated/nodes.rs
@@ -763,6 +763,7 @@ impl EffectExpr {
    pub fn try_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![try]) }
    pub fn unsafe_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![unsafe]) }
    pub fn async_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![async]) }
+    pub fn const_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![const]) }
    pub fn block_expr(&self) -> Option<BlockExpr> { support::child(&self.syntax) }
 }
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
@@ -1251,6 +1252,14 @@ impl TupleStructPat {
    pub fn r_paren_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![')']) }
 }
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct ConstBlockPat {
+    pub(crate) syntax: SyntaxNode,
+}
+impl ConstBlockPat {
+    pub fn const_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![const]) }
+    pub fn block_expr(&self) -> Option<BlockExpr> { support::child(&self.syntax) }
+}
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct RecordPatFieldList {
    pub(crate) syntax: SyntaxNode,
 }
@@ -1369,6 +1378,7 @@ pub enum Pat {
    SlicePat(SlicePat),
    TuplePat(TuplePat),
    TupleStructPat(TupleStructPat),
+    ConstBlockPat(ConstBlockPat),
 }
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum FieldList {
@@ -2772,6 +2782,17 @@ impl AstNode for TupleStructPat {
    }
    fn syntax(&self) -> &SyntaxNode { &self.syntax }
 }
+impl AstNode for ConstBlockPat {
+    fn can_cast(kind: SyntaxKind) -> bool { kind == CONST_BLOCK_PAT }
+    fn cast(syntax: SyntaxNode) -> Option<Self> {
+        if Self::can_cast(syntax.kind()) {
+            Some(Self { syntax })
+        } else {
+            None
+        }
+    }
+    fn syntax(&self) -> &SyntaxNode { &self.syntax }
+}
 impl AstNode for RecordPatFieldList {
    fn can_cast(kind: SyntaxKind) -> bool { kind == RECORD_PAT_FIELD_LIST }
    fn cast(syntax: SyntaxNode) -> Option<Self> {
@@ -3242,12 +3263,15 @@ impl From<TuplePat> for Pat {
 impl From<TupleStructPat> for Pat {
    fn from(node: TupleStructPat) -> Pat { Pat::TupleStructPat(node) }
 }
+impl From<ConstBlockPat> for Pat {
+    fn from(node: ConstBlockPat) -> Pat { Pat::ConstBlockPat(node) }
+}
 impl AstNode for Pat {
    fn can_cast(kind: SyntaxKind) -> bool {
        match kind {
            IDENT_PAT | BOX_PAT | REST_PAT | LITERAL_PAT | MACRO_PAT | OR_PAT | PAREN_PAT
            | PATH_PAT | WILDCARD_PAT | RANGE_PAT | RECORD_PAT | REF_PAT | SLICE_PAT
-            | TUPLE_PAT | TUPLE_STRUCT_PAT => true,
+            | TUPLE_PAT | TUPLE_STRUCT_PAT | CONST_BLOCK_PAT => true,
            _ => false,
        }
    }
@@ -3268,6 +3292,7 @@ impl AstNode for Pat {
            SLICE_PAT => Pat::SlicePat(SlicePat { syntax }),
            TUPLE_PAT => Pat::TuplePat(TuplePat { syntax }),
            TUPLE_STRUCT_PAT => Pat::TupleStructPat(TupleStructPat { syntax }),
+            CONST_BLOCK_PAT => Pat::ConstBlockPat(ConstBlockPat { syntax }),
            _ => return None,
        };
        Some(res)
@@ -3289,6 +3314,7 @@ impl AstNode for Pat {
            Pat::SlicePat(it) => &it.syntax,
            Pat::TuplePat(it) => &it.syntax,
            Pat::TupleStructPat(it) => &it.syntax,
+            Pat::ConstBlockPat(it) => &it.syntax,
        }
    }
 }
@@ -4137,6 +4163,11 @@ impl std::fmt::Display for TupleStructPat {
        std::fmt::Display::fmt(self.syntax(), f)
    }
 }
+impl std::fmt::Display for ConstBlockPat {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        std::fmt::Display::fmt(self.syntax(), f)
+    }
+}
 impl std::fmt::Display for RecordPatFieldList {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        std::fmt::Display::fmt(self.syntax(), f)
diff --git a/crates/syntax/src/ast/make.rs b/crates/syntax/src/ast/make.rs
index ba7e5d2fb..cafa4c198 100644
--- a/crates/syntax/src/ast/make.rs
+++ b/crates/syntax/src/ast/make.rs
@@ -4,6 +4,11 @@
 //! Note that all functions here intended to be stupid constructors, which just
 //! assemble a finish node from immediate children. If you want to do something
 //! smarter than that, it probably doesn't belong in this module.
+//!
+//! Keep in mind that `from_text` functions should be kept private. The public
+//! API should require to assemble every node piecewise. The trick of
+//! `parse(format!())` we use internally is an implementation detail -- long
+//! term, it will be replaced with direct tree manipulation.
 use itertools::Itertools;
 use stdx::format_to;
@@ -16,7 +21,8 @@ pub fn name(text: &str) -> ast::Name {
 pub fn name_ref(text: &str) -> ast::NameRef {
    ast_from_text(&format!("fn f() {{ {}; }}", text))
 }
+// FIXME: replace stringly-typed constructor with a family of typed ctors, a-la
+// `expr_xxx`.
 pub fn ty(text: &str) -> ast::Type {
    ast_from_text(&format!("impl {} for D {{}};", text))
 }
diff --git a/crates/syntax/test_data/parser/inline/ok/0156_const_block_pat.rast b/crates/syntax/test_data/parser/inline/ok/0156_const_block_pat.rast
new file mode 100644
index 000000000..8ff4822c4
--- /dev/null
+++ b/crates/syntax/test_data/parser/inline/ok/0156_const_block_pat.rast
@@ -0,0 +1,76 @@
+SOURCE_FILE@0..78
+  FN@0..77
+    FN_KW@0..2 "fn"
+    WHITESPACE@2..3 " "
+    NAME@3..7
+      IDENT@3..7 "main"
+    PARAM_LIST@7..9
+      L_PAREN@7..8 "("
+      R_PAREN@8..9 ")"
+    WHITESPACE@9..10 " "
+    BLOCK_EXPR@10..77
+      L_CURLY@10..11 "{"
+      WHITESPACE@11..16 "\n    "
+      LET_STMT@16..38
+        LET_KW@16..19 "let"
+        WHITESPACE@19..20 " "
+        CONST_BLOCK_PAT@20..32
+          CONST_KW@20..25 "const"
+          WHITESPACE@25..26 " "
+          BLOCK_EXPR@26..32
+            L_CURLY@26..27 "{"
+            WHITESPACE@27..28 " "
+            LITERAL@28..30
+              INT_NUMBER@28..30 "15"
+            WHITESPACE@30..31 " "
+            R_CURLY@31..32 "}"
+        WHITESPACE@32..33 " "
+        EQ@33..34 "="
+        WHITESPACE@34..35 " "
+        TUPLE_EXPR@35..37
+          L_PAREN@35..36 "("
+          R_PAREN@36..37 ")"
+        SEMICOLON@37..38 ";"
+      WHITESPACE@38..43 "\n    "
+      LET_STMT@43..75
+        LET_KW@43..46 "let"
+        WHITESPACE@46..47 " "
+        CONST_BLOCK_PAT@47..69
+          CONST_KW@47..52 "const"
+          WHITESPACE@52..53 " "
+          BLOCK_EXPR@53..69
+            L_CURLY@53..54 "{"
+            WHITESPACE@54..55 " "
+            EXPR_STMT@55..61
+              CALL_EXPR@55..60
+                PATH_EXPR@55..58
+                  PATH@55..58
+                    PATH_SEGMENT@55..58
+                      NAME_REF@55..58
+                        IDENT@55..58 "foo"
+                ARG_LIST@58..60
+                  L_PAREN@58..59 "("
+                  R_PAREN@59..60 ")"
+              SEMICOLON@60..61 ";"
+            WHITESPACE@61..62 " "
+            CALL_EXPR@62..67
+              PATH_EXPR@62..65
+                PATH@62..65
+                  PATH_SEGMENT@62..65
+                    NAME_REF@62..65
+                      IDENT@62..65 "bar"
+              ARG_LIST@65..67
+                L_PAREN@65..66 "("
+                R_PAREN@66..67 ")"
+            WHITESPACE@67..68 " "
+            R_CURLY@68..69 "}"
+        WHITESPACE@69..70 " "
+        EQ@70..71 "="
+        WHITESPACE@71..72 " "
+        TUPLE_EXPR@72..74
+          L_PAREN@72..73 "("
+          R_PAREN@73..74 ")"
+        SEMICOLON@74..75 ";"
+      WHITESPACE@75..76 "\n"
+      R_CURLY@76..77 "}"
+  WHITESPACE@77..78 "\n"
diff --git a/crates/syntax/test_data/parser/inline/ok/0156_const_block_pat.rs b/crates/syntax/test_data/parser/inline/ok/0156_const_block_pat.rs
new file mode 100644
index 000000000..dce9defac
--- /dev/null
+++ b/crates/syntax/test_data/parser/inline/ok/0156_const_block_pat.rs
@@ -0,0 +1,4 @@
+fn main() {
+    let const { 15 } = ();
+    let const { foo(); bar() } = ();
+}
diff --git a/crates/syntax/test_data/parser/inline/ok/0157_const_block.rast b/crates/syntax/test_data/parser/inline/ok/0157_const_block.rast
new file mode 100644
index 000000000..d5d2c8fe3
--- /dev/null
+++ b/crates/syntax/test_data/parser/inline/ok/0157_const_block.rast
@@ -0,0 +1,23 @@
+SOURCE_FILE@0..21
+  FN@0..20
+    FN_KW@0..2 "fn"
+    WHITESPACE@2..3 " "
+    NAME@3..4
+      IDENT@3..4 "f"
+    PARAM_LIST@4..6
+      L_PAREN@4..5 "("
+      R_PAREN@5..6 ")"
+    WHITESPACE@6..7 " "
+    BLOCK_EXPR@7..20
+      L_CURLY@7..8 "{"
+      WHITESPACE@8..9 " "
+      EFFECT_EXPR@9..18
+        CONST_KW@9..14 "const"
+        WHITESPACE@14..15 " "
+        BLOCK_EXPR@15..18
+          L_CURLY@15..16 "{"
+          WHITESPACE@16..17 " "
+          R_CURLY@17..18 "}"
+      WHITESPACE@18..19 " "
+      R_CURLY@19..20 "}"
+  WHITESPACE@20..21 "\n"
diff --git a/crates/syntax/test_data/parser/inline/ok/0157_const_block.rs b/crates/syntax/test_data/parser/inline/ok/0157_const_block.rs
new file mode 100644
index 000000000..a2e3565a3
--- /dev/null
+++ b/crates/syntax/test_data/parser/inline/ok/0157_const_block.rs
@@ -0,0 +1 @@
+fn f() { const { } }
diff --git a/xtask/Cargo.toml b/xtask/Cargo.toml
index 78a0b54ba..96b4ea448 100644
--- a/xtask/Cargo.toml
+++ b/xtask/Cargo.toml
@@ -15,7 +15,7 @@ flate2 = "1.0"
 pico-args = "0.3.1"
 proc-macro2 = "1.0.8"
 quote = "1.0.2"
-ungrammar = "1.4"
+ungrammar = "1.5"
 walkdir = "2.3.1"
 write-json = "0.1.0"
 xshell = "0.1"
diff --git a/xtask/src/ast_src.rs b/xtask/src/ast_src.rs
index a69ced5cc..2b8012bdd 100644
--- a/xtask/src/ast_src.rs
+++ b/xtask/src/ast_src.rs
@@ -132,6 +132,7 @@ pub(crate) const KINDS_SRC: KindsSrc = KindsSrc {
        "RANGE_PAT",
        "LITERAL_PAT",
        "MACRO_PAT",
+        "CONST_BLOCK_PAT",
        // atoms
        "TUPLE_EXPR",
        "ARRAY_EXPR",