Parse inline const pattern in nested patterns

Author: lowr

crates/parser/src/grammar/patterns.rs

@@ -5,6 +5,7 @@ pub(super) const PATTERN_FIRST: TokenSet =
         T![box],
         T![ref],
         T![mut],
+        T![const],
         T!['('],
         T!['['],
         T![&],
@@ -17,7 +18,7 @@ const PAT_TOP_FIRST: TokenSet = PATTERN_FIRST.union(TokenSet::new(&[T![|]]));
 
 /// Set of possible tokens at the start of a range pattern's end bound.
 const RANGE_PAT_END_FIRST: TokenSet =
-    expressions::LITERAL_FIRST.union(paths::PATH_FIRST).union(TokenSet::new(&[T![-]]));
+    expressions::LITERAL_FIRST.union(paths::PATH_FIRST).union(TokenSet::new(&[T![-], T![const]]));
 
 pub(crate) fn pattern(p: &mut Parser<'_>) {
     pattern_r(p, PAT_RECOVERY_SET);
@@ -499,6 +500,14 @@ fn box_pat(p: &mut Parser<'_>) -> CompletedMarker {
 // fn main() {
 //     let const { 15 } = ();
 //     let const { foo(); bar() } = ();
+//
+//     match 42 {
+//         const { 0 } .. const { 1 } => (),
+//         .. const { 0 } => (),
+//         const { 2 } .. => (),
+//     }
+//
+//     let (const { () },) = ();
 // }
 fn const_block_pat(p: &mut Parser<'_>) -> CompletedMarker {
     assert!(p.at(T![const]));

crates/parser/test_data/parser/inline/ok/0156_const_block_pat.rast

@@ -74,6 +74,126 @@ SOURCE_FILE
             L_PAREN "("
             R_PAREN ")"
           SEMICOLON ";"
+        WHITESPACE "\n\n    "
+        EXPR_STMT
+          MATCH_EXPR
+            MATCH_KW "match"
+            WHITESPACE " "
+            LITERAL
+              INT_NUMBER "42"
+            WHITESPACE " "
+            MATCH_ARM_LIST
+              L_CURLY "{"
+              WHITESPACE "\n        "
+              MATCH_ARM
+                RANGE_PAT
+                  CONST_BLOCK_PAT
+                    CONST_KW "const"
+                    WHITESPACE " "
+                    BLOCK_EXPR
+                      STMT_LIST
+                        L_CURLY "{"
+                        WHITESPACE " "
+                        LITERAL
+                          INT_NUMBER "0"
+                        WHITESPACE " "
+                        R_CURLY "}"
+                  WHITESPACE " "
+                  DOT2 ".."
+                  WHITESPACE " "
+                  CONST_BLOCK_PAT
+                    CONST_KW "const"
+                    WHITESPACE " "
+                    BLOCK_EXPR
+                      STMT_LIST
+                        L_CURLY "{"
+                        WHITESPACE " "
+                        LITERAL
+                          INT_NUMBER "1"
+                        WHITESPACE " "
+                        R_CURLY "}"
+                WHITESPACE " "
+                FAT_ARROW "=>"
+                WHITESPACE " "
+                TUPLE_EXPR
+                  L_PAREN "("
+                  R_PAREN ")"
+                COMMA ","
+              WHITESPACE "\n        "
+              MATCH_ARM
+                RANGE_PAT
+                  DOT2 ".."
+                  WHITESPACE " "
+                  CONST_BLOCK_PAT
+                    CONST_KW "const"
+                    WHITESPACE " "
+                    BLOCK_EXPR
+                      STMT_LIST
+                        L_CURLY "{"
+                        WHITESPACE " "
+                        LITERAL
+                          INT_NUMBER "0"
+                        WHITESPACE " "
+                        R_CURLY "}"
+                WHITESPACE " "
+                FAT_ARROW "=>"
+                WHITESPACE " "
+                TUPLE_EXPR
+                  L_PAREN "("
+                  R_PAREN ")"
+                COMMA ","
+              WHITESPACE "\n        "
+              MATCH_ARM
+                RANGE_PAT
+                  CONST_BLOCK_PAT
+                    CONST_KW "const"
+                    WHITESPACE " "
+                    BLOCK_EXPR
+                      STMT_LIST
+                        L_CURLY "{"
+                        WHITESPACE " "
+                        LITERAL
+                          INT_NUMBER "2"
+                        WHITESPACE " "
+                        R_CURLY "}"
+                  WHITESPACE " "
+                  DOT2 ".."
+                WHITESPACE " "
+                FAT_ARROW "=>"
+                WHITESPACE " "
+                TUPLE_EXPR
+                  L_PAREN "("
+                  R_PAREN ")"
+                COMMA ","
+              WHITESPACE "\n    "
+              R_CURLY "}"
+        WHITESPACE "\n\n    "
+        LET_STMT
+          LET_KW "let"
+          WHITESPACE " "
+          TUPLE_PAT
+            L_PAREN "("
+            CONST_BLOCK_PAT
+              CONST_KW "const"
+              WHITESPACE " "
+              BLOCK_EXPR
+                STMT_LIST
+                  L_CURLY "{"
+                  WHITESPACE " "
+                  TUPLE_EXPR
+                    L_PAREN "("
+                    R_PAREN ")"
+                  WHITESPACE " "
+                  R_CURLY "}"
+            COMMA ","
+            R_PAREN ")"
+          WHITESPACE " "
+          EQ "="
+          WHITESPACE " "
+          TUPLE_EXPR
+            L_PAREN "("
+            R_PAREN ")"
+          SEMICOLON ";"
         WHITESPACE "\n"
         R_CURLY "}"
   WHITESPACE "\n"

crates/parser/test_data/parser/inline/ok/0156_const_block_pat.rs

@@ -1,4 +1,12 @@
 fn main() {
     let const { 15 } = ();
     let const { foo(); bar() } = ();
+
+    match 42 {
+        const { 0 } .. const { 1 } => (),
+        .. const { 0 } => (),
+        const { 2 } .. => (),
+    }
+
+    let (const { () },) = ();
 }