test(fingerprint): Verify rustc extra flags like RUSTFLAGS

I almost overlooked these

Author: epage

tests/testsuite/freshness.rs

@@ -1366,6 +1366,48 @@ fn changing_rustflags_is_cached() {
         .run();
 }
 
+#[cargo_test]
+fn changing_rustc_extra_flags_is_cached() {
+    let p = project().file("src/lib.rs", "").build();
+
+    // This isn't ever cached, we always have to recompile
+    p.cargo("rustc")
+        .with_stderr_data(str![[r#"
+[COMPILING] foo v0.0.1 ([ROOT]/foo)
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .run();
+    p.cargo("rustc -v -- -C linker=cc")
+        .with_stderr_data(str![[r#"
+[DIRTY] foo v0.0.1 ([ROOT]/foo): the profile configuration changed
+[COMPILING] foo v0.0.1 ([ROOT]/foo)
+[RUNNING] `rustc [..]
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .run();
+
+    p.cargo("rustc -v")
+        .with_stderr_data(str![[r#"
+[DIRTY] foo v0.0.1 ([ROOT]/foo): the profile configuration changed
+[COMPILING] foo v0.0.1 ([ROOT]/foo)
+[RUNNING] `rustc [..]
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .run();
+    p.cargo("rustc -v -- -C linker=cc")
+        .with_stderr_data(str![[r#"
+[DIRTY] foo v0.0.1 ([ROOT]/foo): the profile configuration changed
+[COMPILING] foo v0.0.1 ([ROOT]/foo)
+[RUNNING] `rustc [..]
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .run();
+}
+
 #[cargo_test]
 fn update_dependency_mtime_does_not_rebuild() {
     let p = project()

tests/testsuite/freshness_checksum.rs

@@ -1540,6 +1540,52 @@ fn changing_rustflags_is_cached() {
         .run();
 }
 
+#[cargo_test(nightly, reason = "requires -Zchecksum-hash-algorithm")]
+fn changing_rustc_extra_flags_is_cached() {
+    let p = project().file("src/lib.rs", "").build();
+
+    // This isn't ever cached, we always have to recompile
+    p.cargo("rustc -Zchecksum-freshness")
+        .masquerade_as_nightly_cargo(&["checksum-freshness"])
+        .with_stderr_data(str![[r#"
+[COMPILING] foo v0.0.1 ([ROOT]/foo)
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .run();
+    p.cargo("rustc -Zchecksum-freshness -v -- -C linker=cc")
+        .masquerade_as_nightly_cargo(&["checksum-freshness"])
+        .with_stderr_data(str![[r#"
+[DIRTY] foo v0.0.1 ([ROOT]/foo): the profile configuration changed
+[COMPILING] foo v0.0.1 ([ROOT]/foo)
+[RUNNING] `rustc [..]
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .run();
+
+    p.cargo("rustc -Zchecksum-freshness -v")
+        .masquerade_as_nightly_cargo(&["checksum-freshness"])
+        .with_stderr_data(str![[r#"
+[DIRTY] foo v0.0.1 ([ROOT]/foo): the profile configuration changed
+[COMPILING] foo v0.0.1 ([ROOT]/foo)
+[RUNNING] `rustc [..] src/lib.rs [..]
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .run();
+    p.cargo("rustc -Zchecksum-freshness -v -- -C linker=cc")
+        .masquerade_as_nightly_cargo(&["checksum-freshness"])
+        .with_stderr_data(str![[r#"
+[DIRTY] foo v0.0.1 ([ROOT]/foo): the profile configuration changed
+[COMPILING] foo v0.0.1 ([ROOT]/foo)
+[RUNNING] `rustc [..]
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .run();
+}
+
 #[cargo_test(nightly, reason = "requires -Zchecksum-hash-algorithm")]
 fn reuse_panic_build_dep_test() {
     let p = project()