{; ... }   # Block
+{ ... }   # Hash constructor

##</code><code>##

>perl -ce"{ 1, 2; }"
syntax error at -e line 1, near "; }"
-e had compilation errors.

>perl -ce"{; 1, 2; }"
-e syntax OK

>perl -ce"map { f() }, @a"
syntax error at -e line 1, near "},"
-e had compilation errors.

>perl -ce"map +{ f() }, @a"
-e syntax OK