util toml targets: infer file only if not a dir

Any directory entry ending with `.rs`, including directories, were
previously assumed to be files, and could end up as targets.

Now only regular files and symbolic links are inferred.

src/cargo/util/toml/targets.rs

@@ -624,10 +624,10 @@ fn infer_from_directory(directory: &Path) -> Vec<(String, PathBuf)> {
 }
 
 fn infer_any(entry: &DirEntry) -> Option<(String, PathBuf)> {
- if entry.path().extension().and_then(|p| p.to_str()) == Some("rs") {
- infer_file(entry)
- } else if entry.file_type().map(|t| t.is_dir()).ok() == Some(true) {
+ if entry.file_type().map_or(false, |t| t.is_dir()) {
  infer_subdirectory(entry)
+ } else if entry.path().extension().and_then(|p| p.to_str()) == Some("rs") {
+ infer_file(entry)
  } else {
  None
  }

tests/testsuite/build.rs

@@ -5022,6 +5022,18 @@ fn inferred_benchmarks() {
  p.cargo("bench --bench=bar --bench=baz").run();
 }
 
+#[cargo_test]
+fn no_infer_dirs() {
+ let p = project()
+ .file("src/lib.rs", "fn main() {}")
+ .file("examples/dir.rs/dummy", "")
+ .file("benches/dir.rs/dummy", "")
+ .file("tests/dir.rs/dummy", "")
+ .build();
+
+ p.cargo("build --examples --benches --tests").run(); // should not fail with "is a directory"
+}
+
 #[cargo_test]
 fn target_edition() {
  let p = project()