Merge pull request #272 from dtolnay/probe

Move probe.rs out of build script string literal into file

build.rs

@@ -1,41 +1,8 @@
 #![allow(clippy::needless_raw_string_hashes)]
 
 use std::env;
-use std::fs;
 use std::path::Path;
 use std::process::{Command, ExitStatus, Stdio};
-use std::str;
-
-// This code exercises the surface area that we expect of the Error generic
-// member access API. If the current toolchain is able to compile it, then
-// thiserror is able to provide backtrace support.
-const PROBE: &str = r#"
-    #![feature(error_generic_member_access)]
-
-    use std::error::{Error, Request};
-    use std::fmt::{self, Debug, Display};
-
-    struct MyError(Thing);
-    struct Thing;
-
-    impl Debug for MyError {
-        fn fmt(&self, _formatter: &mut fmt::Formatter) -> fmt::Result {
-            unimplemented!()
-        }
-    }
-
-    impl Display for MyError {
-        fn fmt(&self, _formatter: &mut fmt::Formatter) -> fmt::Result {
-            unimplemented!()
-        }
-    }
-
-    impl Error for MyError {
-        fn provide<'a>(&'a self, request: &mut Request<'a>) {
-            request.provide_ref(&self.0);
-        }
-    }
-"#;
 
 fn main() {
     println!("cargo:rerun-if-env-changed=RUSTC_BOOTSTRAP");
@@ -60,8 +27,7 @@ fn compile_probe() -> Option<ExitStatus> {
 
     let rustc = env::var_os("RUSTC")?;
     let out_dir = env::var_os("OUT_DIR")?;
-    let probefile = Path::new(&out_dir).join("probe.rs");
-    fs::write(&probefile, PROBE).ok()?;
+    let probefile = Path::new("build").join("probe.rs");
 
     // Make sure to pick up Cargo rustc configuration.
     let mut cmd = if let Some(wrapper) = env::var_os("RUSTC_WRAPPER") {

build/probe.rs

@@ -0,0 +1,29 @@
+// This code exercises the surface area that we expect of the Error generic
+// member access API. If the current toolchain is able to compile it, then
+// thiserror is able to provide backtrace support.
+
+#![feature(error_generic_member_access)]
+
+use std::error::{Error, Request};
+use std::fmt::{self, Debug, Display};
+
+struct MyError(Thing);
+struct Thing;
+
+impl Debug for MyError {
+    fn fmt(&self, _formatter: &mut fmt::Formatter) -> fmt::Result {
+        unimplemented!()
+    }
+}
+
+impl Display for MyError {
+    fn fmt(&self, _formatter: &mut fmt::Formatter) -> fmt::Result {
+        unimplemented!()
+    }
+}
+
+impl Error for MyError {
+    fn provide<'a>(&'a self, request: &mut Request<'a>) {
+        request.provide_ref(&self.0);
+    }
+}