Re-enable some MSVC tests.

src/cargo/core/compiler/context/compilation_files.rs

@@ -476,6 +476,8 @@ fn compute_metadata<'a, 'cfg>(
     //
     // No metadata for bin because of an issue:
     // - wasm32 rustc/emcc encodes the `.wasm` name in the `.js` (rust-lang/cargo#4535).
+    // - msvc: The path to the PDB is embedded in the executable, and we don't
+    //   want the PDB path to include the hash in it.
     //
     // Two exceptions:
     // 1) Upstream dependencies (we aren't exporting + need to resolve name conflict),

tests/testsuite/collisions.rs

@@ -1,4 +1,3 @@
-#[cfg(not(target_env = "msvc"))]
 use cargo_test_support::basic_manifest;
 use cargo_test_support::project;
 use std::env;
@@ -56,7 +55,6 @@ This may become a hard error in the future; see <https://github.com/rust-lang/ca
 }
 
 #[cargo_test]
-#[cfg(not(target_env = "msvc"))]
 fn collision_example() {
     // Examples in a workspace can easily collide.
     let p = project()
@@ -73,7 +71,9 @@ fn collision_example() {
         .file("b/examples/ex1.rs", "fn main() {}")
         .build();
 
-    p.cargo("build --examples")
+    // `j=1` is required because on Windows you'll get an error due to
+    // two processes writing to the file at the same time.
+    p.cargo("build --examples -j=1")
         .with_stderr_contains("\
 [WARNING] output filename collision.
 The example target `ex1` in package `b v1.0.0 ([..]/foo/b)` has the same output filename as the example target `ex1` in package `a v1.0.0 ([..]/foo/a)`.

tests/testsuite/freshness.rs

@@ -423,7 +423,6 @@ fn changing_bin_paths_common_target_features_caches_targets() {
 }
 
 #[cargo_test]
-#[cfg(not(target_env = "msvc"))]
 fn changing_bin_features_caches_targets() {
     let p = project()
         .file(
@@ -471,22 +470,23 @@ fn changing_bin_features_caches_targets() {
 
     /* Targets should be cached from the first build */
 
-    p.cargo("build")
-        .with_stderr(
-            "\
-[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
-",
-        )
-        .run();
+    let mut e = p.cargo("build");
+    // MSVC does not include hash in binary filename, so it gets recompiled.
+    if cfg!(target_env = "msvc") {
+        e.with_stderr("[COMPILING] foo[..]\n[FINISHED] dev[..]");
+    } else {
+        e.with_stderr("[FINISHED] dev[..]");
+    }
+    e.run();
     p.rename_run("foo", "off2").with_stdout("feature off").run();
 
-    p.cargo("build --features foo")
-        .with_stderr(
-            "\
-[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
-",
-        )
-        .run();
+    let mut e = p.cargo("build --features foo");
+    if cfg!(target_env = "msvc") {
+        e.with_stderr("[COMPILING] foo[..]\n[FINISHED] dev[..]");
+    } else {
+        e.with_stderr("[FINISHED] dev[..]");
+    }
+    e.run();
     p.rename_run("foo", "on2").with_stdout("feature on").run();
 }