func foo(_ fn: () -> Void, a: () -> Void) -> Int? { 0 }

if let i = foo {} a: {} {
  // ...
}

error: consecutive statements on a line must be separated by ';' [statement_same_line_without_semi]
//  if let i = foo {} a: {} {
//                   ^
//                   ;
//  error: labeled block needs 'do' [labeled_block_needs_do]
//  if let i = foo {} a: {} {
//                       ^
//                       do
//  error: consecutive statements on a line must be separated by ';' [statement_same_line_without_semi]
//  if let i = foo {} a: {} {
//                         ^
//                         ;
//  error: top-level statement cannot begin with a closure expression [statement_begins_with_closure]
//  if let i = foo {} a: {} {
//                          ^
//  error: initializer for conditional binding must have Optional type, not '(() -> Void, () -> Void) -> Int?' [condition_optional_element_pattern_not_valid_type]
//  if let i = foo {} a: {} {
//     ^       ~~~
//  error: closure expression is unused [expression_unused_closure]
//  if let i = foo {} a: {} {
//                          ^
//  note: did you mean to use a 'do' statement? [brace_stmt_suggest_do]
//  if let i = foo {} a: {} {
//                          ^
//                          do