defrost RUST_MIN_STACK=ice rustc hello.rs

An earlier commit included the change for a suggestion here.
Unfortunately, it also used unwrap instead of dying properly.
Roll out the ~~rice paper~~ EarlyDiagCtxt before we do anything that
might leave a mess.

3 files changed, 10 insertions, 0 deletions

diff --git a/tests/ui/rustc-env/README.md b/tests/ui/rustc-env/README.md
new file mode 100644
index 00000000000..ff674f3e6cc
--- /dev/null
+++ b/tests/ui/rustc-env/README.md
@@ -0,0 +1,6 @@
+Some environment variables affect rustc's behavior not because they are major compiler interfaces
+but rather because rustc is, ultimately, a Rust program, with debug logging, stack control, etc.
+
+Prefer to group tests that use environment variables to control something about rustc's core UX,
+like "can we parse this number of parens if we raise RUST_MIN_STACK?" with related code for that
+compiler feature.
diff --git a/tests/ui/rustc-env/min-stack-banana.rs b/tests/ui/rustc-env/min-stack-banana.rs
new file mode 100644
index 00000000000..abbb6843710
--- /dev/null
+++ b/tests/ui/rustc-env/min-stack-banana.rs
@@ -0,0 +1,2 @@
+//@ rustc-env:RUST_MIN_STACK=banana
+fn main() {}
diff --git a/tests/ui/rustc-env/min-stack-banana.stderr b/tests/ui/rustc-env/min-stack-banana.stderr
new file mode 100644
index 00000000000..a8b46d8ae44
--- /dev/null
+++ b/tests/ui/rustc-env/min-stack-banana.stderr
@@ -0,0 +1,2 @@
+error: `RUST_MIN_STACK` should be unset or a number of bytes
+