error[E0618]: expected function, found `(..., ..., ..., ...)`
  --> $DIR/long-E0618.rs:10:5
   |
LL | fn foo(x: D) {
   |        - `x` has type `(..., ..., ..., ...)`
LL |     x();
   |     ^--
   |     |
   |     call expression requires function
   |
   = note: the full name for the type has been written to '$TEST_BUILD_DIR/long-E0618.long-type-$LONG_TYPE_HASH.txt'
   = note: consider using `--verbose` to print the full type name to the console

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0618`.