remove unnecessary is wrapper struct

src/cargo/core/compiler/build_config.rs

@@ -25,21 +25,12 @@ pub struct BuildConfig {
     /// Output a build plan to stdout instead of actually compiling.
     pub build_plan: bool,
     /// An optional override of the rustc path for primary units only
-    pub primary_unit_rustc: Option<PrimaryUnitRustc>,
+    pub primary_unit_rustc: Option<ProcessBuilder>,
     pub rustfix_diagnostic_server: RefCell<Option<RustfixDiagnosticServer>>,
     /// Whether or not Cargo should cache compiler output on disk.
     cache_messages: bool,
 }
 
-/// Configuration for subcommand specific rustc override
-#[derive(Debug, Clone)]
-pub struct PrimaryUnitRustc {
-    /// ProcessBuilder to use instead of the default provided by `Rustc`
-    pub proc: ProcessBuilder,
-    /// Configure whether or not to use this as a wrapper around the original rustc process
-    pub is_wrapper: bool,
-}
-
 impl BuildConfig {
     /// Parses all config files to learn about build configuration. Currently
     /// configured options are:

src/cargo/core/compiler/compilation.rs

@@ -78,13 +78,7 @@ impl<'cfg> Compilation<'cfg> {
     pub fn new<'a>(bcx: &BuildContext<'a, 'cfg>) -> CargoResult<Compilation<'cfg>> {
         let mut rustc = bcx.rustc.process();
 
-        let mut primary_unit_rustc_process =
-            bcx.build_config.primary_unit_rustc.clone().map(|mut r| {
-                if r.is_wrapper {
-                    r.proc.arg(&bcx.rustc.path);
-                }
-                r.proc
-            });
+        let mut primary_unit_rustc_process = bcx.build_config.primary_unit_rustc.clone();
 
         if bcx.config.extra_verbose() {
             rustc.display_env_vars();

src/cargo/core/compiler/mod.rs

@@ -24,7 +24,7 @@ use log::debug;
 use same_file::is_same_file;
 use serde::Serialize;
 
-pub use self::build_config::{BuildConfig, CompileMode, MessageFormat, PrimaryUnitRustc};
+pub use self::build_config::{BuildConfig, CompileMode, MessageFormat};
 pub use self::build_context::{BuildContext, FileFlavor, TargetConfig, TargetInfo};
 use self::build_plan::BuildPlan;
 pub use self::compilation::{Compilation, Doctest};

src/cargo/ops/fix.rs

@@ -51,7 +51,6 @@ use log::{debug, trace, warn};
 use rustfix::diagnostics::Diagnostic;
 use rustfix::{self, CodeFix};
 
-use crate::core::compiler::PrimaryUnitRustc;
 use crate::core::Workspace;
 use crate::ops::{self, CompileOptions};
 use crate::util::diagnostic_server::{Message, RustfixDiagnosticServer};
@@ -131,12 +130,12 @@ pub fn fix(ws: &Workspace<'_>, opts: &mut FixOptions<'_>) -> CargoResult<()> {
         server.configure(&mut wrapper);
     }
 
+    let rustc = opts.compile_opts.config.load_global_rustc(Some(ws))?;
+    wrapper.arg(&rustc.path);
+
     // primary crates are compiled using a cargo subprocess to do extra work of applying fixes and
     // repeating build until there are no more changes to be applied
-    opts.compile_opts.build_config.primary_unit_rustc = Some(PrimaryUnitRustc {
-        proc: wrapper,
-        is_wrapper: true,
-    });
+    opts.compile_opts.build_config.primary_unit_rustc = Some(wrapper);
 
     ops::compile(ws, &opts.compile_opts)?;
     Ok(())