compiletest: properly handle revisioned run-rustfix tests

src/tools/compiletest/src/runtest.rs

@@ -4252,7 +4252,7 @@ fn run_ui_test(&self) {
         if self.props.run_rustfix && self.config.compare_mode.is_none() {
             // And finally, compile the fixed code and make sure it both
             // succeeds and has no diagnostics.
-            let rustc = self.make_compile_args(
+            let mut rustc = self.make_compile_args(
                 &self.expected_output_path(UI_FIXED),
                 TargetLocation::ThisFile(self.make_exe_name()),
                 emit_metadata,
@@ -4260,6 +4260,26 @@ fn run_ui_test(&self) {
                 LinkToAux::Yes,
                 Vec::new(),
             );
+
+            // If a test is revisioned, it's fixed source file can be named "a.foo.fixed", which,
+            // well, "a.foo" isn't a valid crate name. So we explicitly mangle the test name
+            // (including the revision) here to avoid the test writer having to manually specify a
+            // `#![crate_name = "..."]` as a workaround. This is okay since we're only checking if
+            // the fixed code is compilable.
+            if self.revision.is_some() {
+                let crate_name =
+                    self.testpaths.file.file_stem().expect("test must have a file stem");
+                // crate name must be alphanumeric or `_`.
+                let crate_name =
+                    crate_name.to_str().expect("crate name implies file name must be valid UTF-8");
+                // replace `a.foo` -> `a__foo` for crate name purposes.
+                // replace `revision-name-with-dashes` -> `revision_name_with_underscore`
+                let crate_name = crate_name.replace(".", "__");
+                let crate_name = crate_name.replace("-", "_");
+                rustc.arg("--crate-name");
+                rustc.arg(crate_name);
+            }
+
             let res = self.compose_and_run_compiler(rustc, None);
             if !res.status.success() {
                 self.fatal_proc_rec("failed to compile fixed code", &res);

tests/ui/compiletest-self-test/run-rustfix-revisions.foo.fixed

@@ -0,0 +1,9 @@
+// Check that revisioned `run-rustfix` does not fail with issues related to `.` in crate name.
+//@ revisions: foo
+//@[foo] run-rustfix
+#![deny(unused_variables)]
+
+fn main() {
+    let _x = 0usize;
+    //~^ ERROR unused variable: `x`
+}

tests/ui/compiletest-self-test/run-rustfix-revisions.foo.stderr

@@ -0,0 +1,14 @@
+error: unused variable: `x`
+  --> $DIR/run-rustfix-revisions.rs:7:9
+   |
+LL |     let x = 0usize;
+   |         ^ help: if this is intentional, prefix it with an underscore: `_x`
+   |
+note: the lint level is defined here
+  --> $DIR/run-rustfix-revisions.rs:4:9
+   |
+LL | #![deny(unused_variables)]
+   |         ^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+

tests/ui/compiletest-self-test/run-rustfix-revisions.rs

@@ -0,0 +1,9 @@
+// Check that revisioned `run-rustfix` does not fail with issues related to `.` in crate name.
+//@ revisions: foo
+//@[foo] run-rustfix
+#![deny(unused_variables)]
+
+fn main() {
+    let x = 0usize;
+    //~^ ERROR unused variable: `x`
+}