error: expected one of `,`, `:`, or `>`, found `=`
  --> $DIR/issue-34334.rs:2:29
   |
LL |     let sr: Vec<(u32, _, _) = vec![];
   |         --                - ^ expected one of `,`, `:`, or `>`
   |         |                 |
   |         |                 maybe try to close unmatched angle bracket
   |         while parsing the type for `sr`
   |
help: you might have meant to end the type parameters here
   |
LL |     let sr: Vec<(u32, _, _)> = vec![];
   |                            +

error[E0277]: a value of type `Vec<(u32, _, _)>` cannot be built from an iterator over elements of type `()`
  --> $DIR/issue-34334.rs:5:87
   |
LL |     let sr2: Vec<(u32, _, _)> = sr.iter().map(|(faction, th_sender, th_receiver)| {}).collect();
   |                                                                                       ^^^^^^^ value of type `Vec<(u32, _, _)>` cannot be built from `std::iter::Iterator<Item=()>`
   |
   = help: the trait `FromIterator<()>` is not implemented for `Vec<(u32, _, _)>`
   = help: the trait `FromIterator<T>` is implemented for `Vec<T>`
note: required by a bound in `collect`
  --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
   |
LL |     fn collect<B: FromIterator<Self::Item>>(self) -> B
   |                   ^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `collect`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0277`.