fix error of RangeFrom in for-loop

crates/ra_parser/src/grammar/expressions/atom.rs

@@ -110,7 +110,13 @@ pub(super) fn atom_expr(p: &mut Parser, r: Restrictions) -> Option<(CompletedMar
             p.bump();
             block_expr(p, Some(m))
         }
-        T!['{'] => block_expr(p, None),
+        T!['{'] => {
+            if r.forbid_structs {
+                return None;
+            } else {
+                block_expr(p, None)
+            }
+        }
         T![return] => return_expr(p),
         T![continue] => continue_expr(p),
         T![break] => break_expr(p, r),
@@ -307,6 +313,16 @@ fn while_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker {
 // fn foo() {
 //     for x in [] {};
 // }
+
+// test for_range_block
+// fn foo() {
+//    for x in 0 .. {
+//        break;
+//    }
+//    for _x in 0 .. (0 .. {1 + 2}).sum::<u32>() {
+//        break;
+//    }
+// }
 fn for_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker {
     assert!(p.at(T![for]));
     let m = m.unwrap_or_else(|| p.start());