compiletest: Don't swallow some error messages.

Author: ehuss

Diff for: src/tools/compiletest/src/runtest.rs

@@ -695,7 +695,7 @@ impl<'test> TestCx<'test> {
     }
 
     fn run_command_to_procres(&self, cmd: &mut Command) -> ProcRes {
-        let output = cmd.output().unwrap_or_else(|_| panic!("failed to exec `{cmd:?}`"));
+        let output = cmd.output().unwrap_or_else(|e| panic!("failed to exec `{cmd:?}`: {e:?}"));
 
         let proc_res = ProcRes {
             status: output.status,
@@ -1216,12 +1216,12 @@ impl<'test> TestCx<'test> {
                 .arg(&exe_file)
                 .arg(&self.config.adb_test_dir)
                 .status()
-                .unwrap_or_else(|_| panic!("failed to exec `{:?}`", adb_path));
+                .unwrap_or_else(|e| panic!("failed to exec `{adb_path:?}`: {e:?}"));
 
             Command::new(adb_path)
                 .args(&["forward", "tcp:5039", "tcp:5039"])
                 .status()
-                .unwrap_or_else(|_| panic!("failed to exec `{:?}`", adb_path));
+                .unwrap_or_else(|e| panic!("failed to exec `{adb_path:?}`: {e:?}"));
 
             let adb_arg = format!(
                 "export LD_LIBRARY_PATH={}; \
@@ -1238,7 +1238,7 @@ impl<'test> TestCx<'test> {
                 .stdout(Stdio::piped())
                 .stderr(Stdio::inherit())
                 .spawn()
-                .unwrap_or_else(|_| panic!("failed to exec `{:?}`", adb_path));
+                .unwrap_or_else(|e| panic!("failed to exec `{adb_path:?}`: {e:?}"));
 
             // Wait for the gdbserver to print out "Listening on port ..."
             // at which point we know that it's started and then we can
@@ -1263,7 +1263,7 @@ impl<'test> TestCx<'test> {
             let Output { status, stdout, stderr } = Command::new(&gdb_path)
                 .args(debugger_opts)
                 .output()
-                .unwrap_or_else(|_| panic!("failed to exec `{:?}`", gdb_path));
+                .unwrap_or_else(|e| panic!("failed to exec `{gdb_path:?}`: {e:?}"));
             let cmdline = {
                 let mut gdb = Command::new(&format!("{}-gdb", self.config.target));
                 gdb.args(debugger_opts);
@@ -2277,7 +2277,7 @@ impl<'test> TestCx<'test> {
         add_dylib_path(&mut command, iter::once(lib_path).chain(aux_path));
 
         let mut child = disable_error_reporting(|| command.spawn())
-            .unwrap_or_else(|_| panic!("failed to exec `{:?}`", &command));
+            .unwrap_or_else(|e| panic!("failed to exec `{command:?}`: {e:?}"));
         if let Some(input) = input {
             child.stdin.as_mut().unwrap().write_all(input.as_bytes()).unwrap();
         }
@@ -3838,8 +3838,8 @@ impl<'test> TestCx<'test> {
                     .open(coverage_file_path.as_path())
                     .expect("could not create or open file");
 
-                if writeln!(file, "{}", self.testpaths.file.display()).is_err() {
-                    panic!("couldn't write to {}", coverage_file_path.display());
+                if let Err(e) = writeln!(file, "{}", self.testpaths.file.display()) {
+                    panic!("couldn't write to {}: {e:?}", coverage_file_path.display());
                 }
             }
         } else if self.props.run_rustfix {