fix: better error message for using the script as a dep

Signed-off-by: Rustin170506 <[email protected]>

Author: 0xPoe

src/cargo/core/source_id.rs

@@ -393,6 +393,9 @@ impl SourceId {
                     .url
                     .to_file_path()
                     .expect("path sources cannot be remote");
+                if crate::util::toml::is_embedded(&path) {
+                    anyhow::bail!("Single file packages cannot be used as dependencies")
+                }
                 Ok(Box::new(PathSource::new(&path, self, gctx)))
             }
             SourceKind::Registry | SourceKind::SparseRegistry => Ok(Box::new(

tests/testsuite/script.rs

@@ -1402,10 +1402,7 @@ Caused by:
   Unable to update [ROOT]/foo/script.rs
 
 Caused by:
-  failed to read `[ROOT]/foo/script.rs/Cargo.toml`
-
-Caused by:
-  Not a directory (os error 20)
+  Single file packages cannot be used as dependencies
 
 "#]])
         .run();