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

Author: Rustin170506

src/cargo/sources/path.rs

@@ -124,6 +124,9 @@ impl<'gctx> PathSource<'gctx> {
     }
 
     fn read_package(&self) -> CargoResult<Package> {
+        if crate::util::toml::is_embedded(&self.path) {
+            anyhow::bail!("The embedded script cannot be used as a dependency");
+        }
         let path = self.path.join("Cargo.toml");
         let pkg = ops::read_package(&path, self.source_id, self.gctx)?;
         Ok(pkg)

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)
+  The embedded script cannot be used as a dependency
 
 "#]])
         .run();