Rollup merge of #147221 - Zalathar:incremental, r=lqd

Forbid `//@ compile-flags: -Cincremental=` in tests

Tests should not try to manually enable incremental compilation with `-Cincremental`, because that typically results in stray directories being created in the repository root.

Also, if the incremental directory is not cleared, there is a risk of interference between successive runs of the same test.

Instead, use the `//@ incremental` directive, which instructs compiletest to handle the details of passing `-Cincremental` with a fresh directory.

1 files changed, 17 insertions, 0 deletions

diff --git a/tests/ui/compiletest-self-test/compile-flags-incremental.rs b/tests/ui/compiletest-self-test/compile-flags-incremental.rs
new file mode 100644
index 00000000000..62a1ad84d8f
--- /dev/null
+++ b/tests/ui/compiletest-self-test/compile-flags-incremental.rs
@@ -0,0 +1,17 @@
+//@ revisions: good bad bad-space
+//@ check-pass
+
+//@[bad] compile-flags: -Cincremental=true
+//@[bad] should-fail
+
+//@[bad-space] compile-flags:  -C  incremental=dir
+//@[bad-space] should-fail
+
+fn main() {}
+
+// Tests should not try to manually enable incremental compilation with
+// `-Cincremental`, because that typically results in stray directories being
+// created in the repository root.
+//
+// Instead, use the `//@ incremental` directive, which instructs compiletest
+// to handle the details of passing `-Cincremental` with a fresh directory.