1 files changed, 32 insertions, 0 deletions
diff --git a/tests/run-coverage/generator.coverage b/tests/run-coverage/generator.coverage
new file mode 100644
index 00000000000..0fb3808ff2e
--- /dev/null
+++ b/tests/run-coverage/generator.coverage
@@ -0,0 +1,32 @@
+    1|       |#![feature(generators, generator_trait)]
+    2|       |
+    3|       |use std::ops::{Generator, GeneratorState};
+    4|       |use std::pin::Pin;
+    5|       |
+    6|       |// The following implementation of a function called from a `yield` statement
+    7|       |// (apparently requiring the Result and the `String` type or constructor)
+    8|       |// creates conditions where the `generator::StateTransform` MIR transform will
+    9|       |// drop all `Counter` `Coverage` statements from a MIR. `simplify.rs` has logic
+   10|       |// to handle this condition, and still report dead block coverage.
+   11|      1|fn get_u32(val: bool) -> Result<u32, String> {
+   12|      1|    if val { Ok(1) } else { Err(String::from("some error")) }
+                                          ^0
+   13|      1|}
+   14|       |
+   15|      1|fn main() {
+   16|      1|    let is_true = std::env::args().len() == 1;
+   17|      1|    let mut generator = || {
+   18|      1|        yield get_u32(is_true);
+   19|      1|        return "foo";
+   20|      1|    };
+   21|       |
+   22|      1|    match Pin::new(&mut generator).resume(()) {
+   23|      1|        GeneratorState::Yielded(Ok(1)) => {}
+   24|      0|        _ => panic!("unexpected return from resume"),
+   25|       |    }
+   26|      1|    match Pin::new(&mut generator).resume(()) {
+   27|      1|        GeneratorState::Complete("foo") => {}
+   28|      0|        _ => panic!("unexpected return from resume"),
+   29|       |    }
+   30|      1|}
+