msvc: #1687: handle case where output file is a directory

src/compiler/msvc.rs

@@ -732,7 +732,20 @@ pub fn parse_arguments(
             );
         }
         Some(o) => {
-            if o.extension().is_none() && compilation {
+            if o.as_os_str()
+                .to_string_lossy()
+                .ends_with(std::path::MAIN_SEPARATOR) {
+                match Path::new(&input).file_name() {
+                    Some(i) => outputs.insert(
+                        "obj",
+                        ArtifactDescriptor {
+                            path: o.join(Path::new(i)).with_extension("obj"),
+                            optional: false,
+                        },
+                    ),
+                    None => cannot_cache!("invalid input file"),
+                };
+            } else if o.extension().is_none() {
                 outputs.insert(
                     "obj",
                     ArtifactDescriptor {
@@ -1833,6 +1846,38 @@ mod test {
         assert!(msvc_show_includes);
     }
 
+    #[test]
+    fn parse_argument_output_file_trailing_backslash() {
+        let args = ovec!["-c", "foo.c", "/Fomyrelease\\folder\\"];
+        let ParsedArguments {
+            input,
+            language,
+            outputs,
+            preprocessor_args,
+            msvc_show_includes,
+            common_args,
+            ..
+        } = match parse_arguments(args) {
+            CompilerArguments::Ok(args) => args,
+            o => panic!("Got unexpected parse result: {:?}", o),
+        };
+        assert_eq!(Some("foo.c"), input.to_str());
+        assert_eq!(Language::C, language);
+        assert_map_contains!(
+            outputs,
+            (
+                "obj",
+                ArtifactDescriptor {
+                    path: PathBuf::from("myrelease/folder/foo.obj"),
+                    optional: false
+                }
+            )
+        );
+        assert!(preprocessor_args.is_empty());
+        assert!(common_args.is_empty());
+        assert!(!msvc_show_includes);
+    }
+
     #[test]
     fn test_parse_arguments_pdb() {
         let args = ovec!["-c", "foo.c", "-Zi", "-Fdfoo.pdb", "-Fofoo.obj"];