Pass through --remap-path-prefix argument. (#2270)

* Pass through `--remap-path-prefix` argument.

* Nothing is TooHard anymore in the Rust world!

* Add a test for `--remap-path-prefix`

Author: ColinFinck

src/compiler/rust.rs

@@ -1000,7 +1000,6 @@ impl IntoArg for ArgTarget {
 
 ArgData! {
     TooHardFlag,
-    TooHard(OsString),
     TooHardPath(PathBuf),
     NotCompilationFlag,
     NotCompilation(OsString),
@@ -1045,7 +1044,7 @@ counted_array!(static ARGS: [ArgInfo<ArgData>; _] = [
     take_arg!("--out-dir", PathBuf, CanBeSeparated('='), OutDir),
     take_arg!("--pretty", OsString, CanBeSeparated('='), NotCompilation),
     take_arg!("--print", OsString, CanBeSeparated('='), NotCompilation),
-    take_arg!("--remap-path-prefix", OsString, CanBeSeparated('='), TooHard),
+    take_arg!("--remap-path-prefix", OsString, CanBeSeparated('='), PassThrough),
     take_arg!("--sysroot", PathBuf, CanBeSeparated('='), TooHardPath),
     take_arg!("--target", ArgTarget, CanBeSeparated('='), Target),
     take_arg!("--unpretty", OsString, CanBeSeparated('='), NotCompilation),
@@ -1088,7 +1087,7 @@ fn parse_arguments(arguments: &[OsString], cwd: &Path) -> CompilerArguments<Pars
     for arg in ArgsIter::new(arguments.iter().cloned(), &ARGS[..]) {
         let arg = try_or_cannot_cache!(arg, "argument parse");
         match arg.get_data() {
-            Some(TooHardFlag) | Some(TooHard(_)) | Some(TooHardPath(_)) => {
+            Some(TooHardFlag) | Some(TooHardPath(_)) => {
                 cannot_cache!(arg.flag_str().expect("Can't be Argument::Raw/UnknownFlag",))
             }
             Some(NotCompilationFlag) | Some(NotCompilation(_)) => {
@@ -3799,6 +3798,34 @@ proc_macro false
         assert_eq!(h.gcno, Some("foo-a1b6419f8321841f.gcno".into()));
     }
 
+    #[test]
+    fn test_parse_remap_path_prefix() {
+        let h = parses!(
+            "--crate-name",
+            "foo",
+            "--crate-type",
+            "lib",
+            "./src/lib.rs",
+            "--emit=dep-info,link",
+            "--out-dir",
+            "/out",
+            "--remap-path-prefix",
+            "/home/test=~",
+            "--remap-path-prefix",
+            "/root=~"
+        );
+        assert!(h.arguments.contains(&Argument::WithValue(
+            "--remap-path-prefix",
+            ArgData::PassThrough(OsString::from("/home/test=~")),
+            ArgDisposition::Separated
+        )));
+        assert!(h.arguments.contains(&Argument::WithValue(
+            "--remap-path-prefix",
+            ArgData::PassThrough(OsString::from("/root=~")),
+            ArgDisposition::Separated
+        )));
+    }
+
     #[test]
     fn test_parse_target() {
         // Parse a --target argument that is a string (not a path to a .json file).