docs: update the comment and add a test to half_open_range_pat

Author: dzvon

crates/parser/src/grammar/patterns.rs

@@ -126,6 +126,8 @@ fn pattern_single_r(p: &mut Parser<'_>, recovery_set: TokenSet) {
                 //             ^
                 // `[0..]`
                 //      ^
+                // `0 .. if`
+                //       ^
                 if matches!(
                     p.current(),
                     T![=] | T![,] | T![:] | T![')'] | T!['}'] | T![']'] | T![if]
@@ -134,6 +136,11 @@ fn pattern_single_r(p: &mut Parser<'_>, recovery_set: TokenSet) {
                     // fn f() {
                     //     let 0 .. = 1u32;
                     //     let 0..: _ = 1u32;
+                    //
+                    //     match 42 {
+                    //         0 .. if true => (),
+                    //         _ => (),
+                    //     }
                     // }
                 } else {
                     atom_pat(p, recovery_set);

crates/parser/test_data/parser/inline/ok/0166_half_open_range_pat.rast

@@ -46,6 +46,49 @@ SOURCE_FILE
           LITERAL
             INT_NUMBER "1u32"
           SEMICOLON ";"
+        WHITESPACE "\n\n    "
+        MATCH_EXPR
+          MATCH_KW "match"
+          WHITESPACE " "
+          LITERAL
+            INT_NUMBER "42"
+          WHITESPACE " "
+          MATCH_ARM_LIST
+            L_CURLY "{"
+            WHITESPACE "\n        "
+            MATCH_ARM
+              RANGE_PAT
+                LITERAL_PAT
+                  LITERAL
+                    INT_NUMBER "0"
+                WHITESPACE " "
+                DOT2 ".."
+              WHITESPACE " "
+              MATCH_GUARD
+                IF_KW "if"
+                WHITESPACE " "
+                LITERAL
+                  TRUE_KW "true"
+              WHITESPACE " "
+              FAT_ARROW "=>"
+              WHITESPACE " "
+              TUPLE_EXPR
+                L_PAREN "("
+                R_PAREN ")"
+              COMMA ","
+            WHITESPACE "\n        "
+            MATCH_ARM
+              WILDCARD_PAT
+                UNDERSCORE "_"
+              WHITESPACE " "
+              FAT_ARROW "=>"
+              WHITESPACE " "
+              TUPLE_EXPR
+                L_PAREN "("
+                R_PAREN ")"
+              COMMA ","
+            WHITESPACE "\n    "
+            R_CURLY "}"
         WHITESPACE "\n"
         R_CURLY "}"
   WHITESPACE "\n"

crates/parser/test_data/parser/inline/ok/0166_half_open_range_pat.rs

@@ -1,4 +1,9 @@
 fn f() {
     let 0 .. = 1u32;
     let 0..: _ = 1u32;
+
+    match 42 {
+        0 .. if true => (),
+        _ => (),
+    }
 }