run test in tmp dir and emit artifacts there

otherwise the test would build in the source root's `target` folder

Author: lqd

tests/run-make/rustc-crates-on-stable/rmake.rs

@@ -1,36 +1,43 @@
 //! Checks if selected rustc crates can be compiled on the stable channel (or a "simulation" of it).
 //! These crates are designed to be used by downstream users.
 
-use run_make_support::{cargo, rustc_path, source_root};
+use run_make_support::{cargo, run_in_tmpdir, rustc_path, source_root};
 
 fn main() {
-    // Use the stage0 beta cargo for the compilation (it shouldn't really matter which cargo we use)
-    let cargo = cargo()
-        // This is required to allow using nightly cargo features (public-dependency) with beta
-        // cargo
-        .env("RUSTC_BOOTSTRAP", "1")
-        .env("RUSTC_STAGE", "0") // Ensure `proc-macro2`'s nightly detection is disabled
-        .env("RUSTC", rustc_path())
-        .arg("build")
-        .arg("--manifest-path")
-        .arg(source_root().join("Cargo.toml"))
-        .args(&[
-            "--config",
-            r#"workspace.exclude=["library/core"]"#,
-            // We want to disallow all nightly features, to simulate a stable build
-            // public-dependency needs to be enabled for cargo to work
-            "-Zallow-features=public-dependency",
-            // Avoid depending on transitive rustc crates
-            "--no-default-features",
-            // Check that these crates can be compiled on "stable"
-            "-p",
-            "rustc_type_ir",
-            "-p",
-            "rustc_next_trait_solver",
-            "-p",
-            "rustc_pattern_analysis",
-            "-p",
-            "rustc_lexer",
-        ])
-        .run();
+    run_in_tmpdir(|| {
+        // Use the stage0 beta cargo for the compilation (it shouldn't really matter which cargo we
+        // use)
+        let cargo = cargo()
+            // This is required to allow using nightly cargo features (public-dependency) with beta
+            // cargo
+            .env("RUSTC_BOOTSTRAP", "1")
+            .env("RUSTC_STAGE", "0") // Ensure `proc-macro2`'s nightly detection is disabled
+            .env("RUSTC", rustc_path())
+            .arg("build")
+            .arg("--manifest-path")
+            .arg(source_root().join("Cargo.toml"))
+            .args(&[
+                "--config",
+                r#"workspace.exclude=["library/core"]"#,
+                // We want to disallow all nightly features, to simulate a stable build
+                // public-dependency needs to be enabled for cargo to work
+                "-Zallow-features=public-dependency",
+                // Avoid depending on transitive rustc crates
+                "--no-default-features",
+                // Emit artifacts in this temporary directory, not in the source_root's `target`
+                // folder
+                "--target-dir",
+                ".",
+                // Check that these crates can be compiled on "stable"
+                "-p",
+                "rustc_type_ir",
+                "-p",
+                "rustc_next_trait_solver",
+                "-p",
+                "rustc_pattern_analysis",
+                "-p",
+                "rustc_lexer",
+            ])
+            .run();
+    });
 }