Add a general mechanism for setting rustflags in Cargo that only applies to the current crate. Add tests to ensure --rustflags options are only set for the current crate and not any dependencies.

Author: ridwanabdillahi

src/bin/cargo/commands/bench.rs

@@ -48,6 +48,7 @@ pub fn cli() -> App {
         ))
         .arg_unit_graph()
         .arg_timings()
+        .arg_rustflags()
         .after_help("Run `cargo help bench` for more detailed information.\n")
 }
 

src/bin/cargo/commands/build.rs

@@ -45,6 +45,7 @@ pub fn cli() -> App {
         .arg_unit_graph()
         .arg_future_incompat_report()
         .arg_timings()
+        .arg_rustflags()
         .after_help("Run `cargo help build` for more detailed information.\n")
 }
 

src/bin/cargo/commands/check.rs

@@ -37,6 +37,7 @@ pub fn cli() -> App {
         .arg_unit_graph()
         .arg_future_incompat_report()
         .arg_timings()
+        .arg_rustflags()
         .after_help("Run `cargo help check` for more detailed information.\n")
 }
 

src/bin/cargo/commands/doc.rs

@@ -40,6 +40,7 @@ pub fn cli() -> App {
         .arg_ignore_rust_version()
         .arg_unit_graph()
         .arg_timings()
+        .arg_rustflags()
         .after_help("Run `cargo help doc` for more detailed information.\n")
 }
 

src/bin/cargo/commands/fix.rs

@@ -54,6 +54,7 @@ pub fn cli() -> App {
         ))
         .arg_ignore_rust_version()
         .arg_timings()
+        .arg_rustflags()
         .after_help("Run `cargo help fix` for more detailed information.\n")
 }
 

src/bin/cargo/commands/install.rs

@@ -82,6 +82,7 @@ pub fn cli() -> App {
         )
         .arg_message_format()
         .arg_timings()
+        .arg_rustflags()
         .after_help("Run `cargo help install` for more detailed information.\n")
 }
 

src/bin/cargo/commands/package.rs

@@ -35,6 +35,7 @@ pub fn cli() -> App {
         )
         .arg_manifest_path()
         .arg_jobs()
+        .arg_rustflags()
         .after_help("Run `cargo help package` for more detailed information.\n")
 }
 

src/bin/cargo/commands/run.rs

@@ -32,6 +32,7 @@ pub fn cli() -> App {
         .arg_unit_graph()
         .arg_ignore_rust_version()
         .arg_timings()
+        .arg_rustflags()
         .after_help("Run `cargo help run` for more detailed information.\n")
 }
 

src/bin/cargo/commands/test.rs

@@ -56,6 +56,7 @@ pub fn cli() -> App {
         .arg_unit_graph()
         .arg_future_incompat_report()
         .arg_timings()
+        .arg_rustflags()
         .after_help(
             "Run `cargo help test` for more detailed information.\n\
              Run `cargo test -- --help` for test binary options.\n",

src/cargo/core/compiler/fingerprint.rs

@@ -1302,13 +1302,16 @@ fn calculate_normal(cx: &mut Context<'_, '_>, unit: &Unit) -> CargoResult<Finger
     // Fill out a bunch more information that we'll be tracking typically
     // hashed to take up less space on disk as we just need to know when things
     // change.
-    let extra_flags = if unit.mode.is_doc() {
+    let mut rustflags = if unit.mode.is_doc() {
         cx.bcx.rustdocflags_args(unit)
     } else {
         cx.bcx.rustflags_args(unit)
     }
     .to_vec();
 
+    // Append the command line user specified RUSTFLAGS to the env var or config RUSTFLAGS.
+    rustflags.extend(unit.rustflags.iter().map(InternedString::to_string));
+
     let profile_hash = util::hash_u64((
         &unit.profile,
         unit.mode,
@@ -1345,7 +1348,7 @@ fn calculate_normal(cx: &mut Context<'_, '_>, unit: &Unit) -> CargoResult<Finger
         metadata,
         config: config.finish(),
         compile_kind,
-        rustflags: extra_flags,
+        rustflags,
         fs_status: FsStatus::Stale,
         outputs,
     })