Merge #7010

7010: Update ungrammar for const block patterns r=matklad a=Veykril

Fixes #6848

Adds const blocks and const block patterns to the AST and parses them.

Blocked on https://github.com/rust-analyzer/ungrammar/pull/17/, will merge that PR there once this one gets the OK so I can remove the local ungrammar dependency path and fix the Cargo.lock.

Co-authored-by: Lukas Wirth <[email protected]>

10 files changed, 168 insertions, 4 deletions

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/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/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/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 @@
+[email protected]
+  [email protected]
+    [email protected] "fn"
+    [email protected] " "
+    [email protected]
+      [email protected] "main"
+    [email protected]
+      [email protected] "("
+      [email protected] ")"
+    [email protected] " "
+    [email protected]
+      [email protected] "{"
+      [email protected] "\n    "
+      [email protected]
+        [email protected] "let"
+        [email protected] " "
+        [email protected]
+          [email protected] "const"
+          [email protected] " "
+          [email protected]
+            [email protected] "{"
+            [email protected] " "
+            [email protected]
+              [email protected] "15"
+            [email protected] " "
+            [email protected] "}"
+        [email protected] " "
+        [email protected] "="
+        [email protected] " "
+        [email protected]
+          [email protected] "("
+          [email protected] ")"
+        [email protected] ";"
+      [email protected] "\n    "
+      [email protected]
+        [email protected] "let"
+        [email protected] " "
+        [email protected]
+          [email protected] "const"
+          [email protected] " "
+          [email protected]
+            [email protected] "{"
+            [email protected] " "
+            [email protected]
+              [email protected]
+                [email protected]
+                  [email protected]
+                    [email protected]
+                      [email protected]
+                        [email protected] "foo"
+                [email protected]
+                  [email protected] "("
+                  [email protected] ")"
+              [email protected] ";"
+            [email protected] " "
+            [email protected]
+              [email protected]
+                [email protected]
+                  [email protected]
+                    [email protected]
+                      [email protected] "bar"
+              [email protected]
+                [email protected] "("
+                [email protected] ")"
+            [email protected] " "
+            [email protected] "}"
+        [email protected] " "
+        [email protected] "="
+        [email protected] " "
+        [email protected]
+          [email protected] "("
+          [email protected] ")"
+        [email protected] ";"
+      [email protected] "\n"
+      [email protected] "}"
+  [email protected] "\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 @@
+[email protected]
+  [email protected]
+    [email protected] "fn"
+    [email protected] " "
+    [email protected]
+      [email protected] "f"
+    [email protected]
+      [email protected] "("
+      [email protected] ")"
+    [email protected] " "
+    [email protected]
+      [email protected] "{"
+      [email protected] " "
+      [email protected]
+        [email protected] "const"
+        [email protected] " "
+        [email protected]
+          [email protected] "{"
+          [email protected] " "
+          [email protected] "}"
+      [email protected] " "
+      [email protected] "}"
+  [email protected] "\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 { } }