rustc_driver: avoid fallible conversions

Use `std::path::PathBuf` rather than `String`; use `std::env::var_os`
rather than `std::env::var`. These changes avoid a number of error paths
which can arise in the presence of non-UTF-8 paths.

1 files changed, 3 insertions, 3 deletions

diff --git a/compiler/rustc_driver_impl/src/session_diagnostics.rs b/compiler/rustc_driver_impl/src/session_diagnostics.rs
index 5eb587c54d9..442989f8de8 100644
--- a/compiler/rustc_driver_impl/src/session_diagnostics.rs
+++ b/compiler/rustc_driver_impl/src/session_diagnostics.rs
@@ -52,13 +52,13 @@ pub(crate) struct IceVersion<'a> {
 #[derive(Diagnostic)]
 #[diag(driver_impl_ice_path)]
 pub(crate) struct IcePath {
-    pub path: String,
+    pub path: std::path::PathBuf,
 }
 
 #[derive(Diagnostic)]
 #[diag(driver_impl_ice_path_error)]
 pub(crate) struct IcePathError {
-    pub path: String,
+    pub path: std::path::PathBuf,
     pub error: String,
     #[subdiagnostic]
     pub env_var: Option<IcePathErrorEnv>,
@@ -67,7 +67,7 @@ pub(crate) struct IcePathError {
 #[derive(Subdiagnostic)]
 #[note(driver_impl_ice_path_error_env)]
 pub(crate) struct IcePathErrorEnv {
-    pub env_var: String,
+    pub env_var: std::path::PathBuf,
 }
 
 #[derive(Diagnostic)]