    1|       |#![allow(unused_assignments, unused_variables)]
    2|       |// compile-flags: -C opt-level=3 # validates coverage now works with optimizations
    3|       |use std::fmt::Debug;
    4|       |
    5|      1|pub fn used_function() {
    6|      1|    // Initialize test constants in a way that cannot be determined at compile time, to ensure
    7|      1|    // rustc and LLVM cannot optimize out statements (or coverage counters) downstream from
    8|      1|    // dependent conditions.
    9|      1|    let is_true = std::env::args().len() == 1;
   10|      1|    let mut countdown = 0;
   11|      1|    if is_true {
   12|      1|        countdown = 10;
   13|      1|    }
                   ^0
   14|      1|    use_this_lib_crate();
   15|      1|}
   16|       |
   17|      2|pub fn used_only_from_bin_crate_generic_function<T: Debug>(arg: T) {
   18|      2|    println!("used_only_from_bin_crate_generic_function with {:?}", arg);
   19|      2|}
  ------------------
  | Unexecuted instantiation: used_crate::used_only_from_bin_crate_generic_function::<_>
  ------------------
  | used_crate::used_only_from_bin_crate_generic_function::<&alloc::vec::Vec<i32>>:
  |   17|      1|pub fn used_only_from_bin_crate_generic_function<T: Debug>(arg: T) {
  |   18|      1|    println!("used_only_from_bin_crate_generic_function with {:?}", arg);
  |   19|      1|}
  ------------------
  | used_crate::used_only_from_bin_crate_generic_function::<&str>:
  |   17|      1|pub fn used_only_from_bin_crate_generic_function<T: Debug>(arg: T) {
  |   18|      1|    println!("used_only_from_bin_crate_generic_function with {:?}", arg);
  |   19|      1|}
  ------------------
   20|       |// Expect for above function: `Unexecuted instantiation` (see below)
   21|      2|pub fn used_only_from_this_lib_crate_generic_function<T: Debug>(arg: T) {
   22|      2|    println!("used_only_from_this_lib_crate_generic_function with {:?}", arg);
   23|      2|}
  ------------------
  | used_crate::used_only_from_this_lib_crate_generic_function::<&str>:
  |   21|      1|pub fn used_only_from_this_lib_crate_generic_function<T: Debug>(arg: T) {
  |   22|      1|    println!("used_only_from_this_lib_crate_generic_function with {:?}", arg);
  |   23|      1|}
  ------------------
  | used_crate::used_only_from_this_lib_crate_generic_function::<alloc::vec::Vec<i32>>:
  |   21|      1|pub fn used_only_from_this_lib_crate_generic_function<T: Debug>(arg: T) {
  |   22|      1|    println!("used_only_from_this_lib_crate_generic_function with {:?}", arg);
  |   23|      1|}
  ------------------
   24|       |
   25|      2|pub fn used_from_bin_crate_and_lib_crate_generic_function<T: Debug>(arg: T) {
   26|      2|    println!("used_from_bin_crate_and_lib_crate_generic_function with {:?}", arg);
   27|      2|}
  ------------------
  | used_crate::used_from_bin_crate_and_lib_crate_generic_function::<&str>:
  |   25|      1|pub fn used_from_bin_crate_and_lib_crate_generic_function<T: Debug>(arg: T) {
  |   26|      1|    println!("used_from_bin_crate_and_lib_crate_generic_function with {:?}", arg);
  |   27|      1|}
  ------------------
  | used_crate::used_from_bin_crate_and_lib_crate_generic_function::<alloc::vec::Vec<i32>>:
  |   25|      1|pub fn used_from_bin_crate_and_lib_crate_generic_function<T: Debug>(arg: T) {
  |   26|      1|    println!("used_from_bin_crate_and_lib_crate_generic_function with {:?}", arg);
  |   27|      1|}
  ------------------
   28|       |
   29|      2|pub fn used_with_same_type_from_bin_crate_and_lib_crate_generic_function<T: Debug>(arg: T) {
   30|      2|    println!("used_with_same_type_from_bin_crate_and_lib_crate_generic_function with {:?}", arg);
   31|      2|}
  ------------------
  | used_crate::used_with_same_type_from_bin_crate_and_lib_crate_generic_function::<&str>:
  |   29|      1|pub fn used_with_same_type_from_bin_crate_and_lib_crate_generic_function<T: Debug>(arg: T) {
  |   30|      1|    println!("used_with_same_type_from_bin_crate_and_lib_crate_generic_function with {:?}", arg);
  |   31|      1|}
  ------------------
  | used_crate::used_with_same_type_from_bin_crate_and_lib_crate_generic_function::<&str>:
  |   29|      1|pub fn used_with_same_type_from_bin_crate_and_lib_crate_generic_function<T: Debug>(arg: T) {
  |   30|      1|    println!("used_with_same_type_from_bin_crate_and_lib_crate_generic_function with {:?}", arg);
  |   31|      1|}
  ------------------
   32|       |
   33|      0|pub fn unused_generic_function<T: Debug>(arg: T) {
   34|      0|    println!("unused_generic_function with {:?}", arg);
   35|      0|}
   36|       |
   37|      0|pub fn unused_function() {
   38|      0|    let is_true = std::env::args().len() == 1;
   39|      0|    let mut countdown = 2;
   40|      0|    if !is_true {
   41|      0|        countdown = 20;
   42|      0|    }
   43|      0|}
   44|       |
   45|      0|fn unused_private_function() {
   46|      0|    let is_true = std::env::args().len() == 1;
   47|      0|    let mut countdown = 2;
   48|      0|    if !is_true {
   49|      0|        countdown = 20;
   50|      0|    }
   51|      0|}
   52|       |
   53|      1|fn use_this_lib_crate() {
   54|      1|    used_from_bin_crate_and_lib_crate_generic_function("used from library used_crate.rs");
   55|      1|    used_with_same_type_from_bin_crate_and_lib_crate_generic_function(
   56|      1|        "used from library used_crate.rs",
   57|      1|    );
   58|      1|    let some_vec = vec![5, 6, 7, 8];
   59|      1|    used_only_from_this_lib_crate_generic_function(some_vec);
   60|      1|    used_only_from_this_lib_crate_generic_function("used ONLY from library used_crate.rs");
   61|      1|}
   62|       |
   63|       |// FIXME(#79651): "Unexecuted instantiation" errors appear in coverage results,
   64|       |// for example:
   65|       |//
   66|       |// | Unexecuted instantiation: used_crate::used_only_from_bin_crate_generic_function::<_>
   67|       |//
   68|       |// These notices appear when `llvm-cov` shows instantiations. This may be a
   69|       |// default option, but it can be suppressed with:
   70|       |//
   71|       |// ```shell
   72|       |// $ `llvm-cov show --show-instantiations=0 ...`
   73|       |// ```
   74|       |//
   75|       |// The notice is triggered because the function is unused by the library itself,
   76|       |// and when the library is compiled, a synthetic function is generated, so
   77|       |// unused function coverage can be reported. Coverage can be skipped for unused
   78|       |// generic functions with:
   79|       |//
   80|       |// ```shell
   81|       |// $ `rustc -Zunstable-options -C instrument-coverage=except-unused-generics ...`
   82|       |// ```
   83|       |//
   84|       |// Even though this function is used by `uses_crate.rs` (and
   85|       |// counted), with substitutions for `T`, those instantiations are only generated
   86|       |// when the generic function is actually used (from the binary, not from this
   87|       |// library crate). So the test result shows coverage for all instantiated
   88|       |// versions and their generic type substitutions, plus the `Unexecuted
   89|       |// instantiation` message for the non-substituted version. This is valid, but
   90|       |// unfortunately a little confusing.
   91|       |//
   92|       |// The library crate has its own coverage map, and the only way to show unused
   93|       |// coverage of a generic function is to include the generic function in the
   94|       |// coverage map, marked as an "unused function". If the library were used by
   95|       |// another binary that never used this generic function, then it would be valid
   96|       |// to show the unused generic, with unknown substitution (`_`).
   97|       |//
   98|       |// The alternative is to exclude all generics from being included in the "unused
   99|       |// functions" list, which would then omit coverage results for
  100|       |// `unused_generic_function<T>()`, below.

