syntax: Don't assume std exists for tests

This commit removes the injection of `std::env::args()` from `--test` expanded
code, relying on the test runner itself to call this funciton. This is more
hygienic because we can't assume that `std` exists at the top layer all the
time, and it meaks the injected test module entirely self contained.

Author: alexcrichton

src/libstd/lib.rs

@@ -414,11 +414,3 @@ pub mod __rand {
 // the rustdoc documentation for primitive types. Using `include!`
 // because rustdoc only looks for these modules at the crate level.
 include!("primitive_docs.rs");
-
-// The expansion of --test has a few references to `::std::$foo` so this module
-// is necessary to get things to compile.
-#[cfg(test)]
-mod std {
-    pub use option;
-    pub use realstd::env;
-}

src/libstd/process.rs

@@ -815,7 +815,7 @@ mod tests {
     #[cfg(target_os="android")]
     #[test]
     fn test_inherit_env() {
-        use std::env;
+        use env;
 
         let mut result = env_cmd().output().unwrap();
         let output = String::from_utf8(result.stdout).unwrap();

src/libstd/sys/unix/thread.rs

@@ -166,6 +166,7 @@ impl Drop for Thread {
           not(target_os = "netbsd"),
           not(target_os = "openbsd")))]
 pub mod guard {
+    #[cfg(stage0)]
     use prelude::v1::*;
 
     pub unsafe fn current() -> Option<usize> { None }

src/libstd/sys/windows/thread.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#[cfg(stage0)]
 use prelude::v1::*;
 
 use alloc::boxed::FnBox;
@@ -87,6 +86,7 @@ impl Thread {
 }
 
 pub mod guard {
+    #[cfg(stage0)]
     use prelude::v1::*;
 
     pub unsafe fn current() -> Option<usize> { None }

src/libstd/thread/local.rs

@@ -329,6 +329,7 @@ mod imp {
     // Due to rust-lang/rust#18804, make sure this is not generic!
     #[cfg(target_os = "linux")]
     unsafe fn register_dtor(t: *mut u8, dtor: unsafe extern fn(*mut u8)) {
+        use prelude::v1::*;
         use mem;
         use libc;
         use sys_common::thread_local as os;

src/libsyntax/test.rs

@@ -450,18 +450,11 @@ fn mk_main(cx: &mut TestCtxt) -> P<ast::Item> {
     // test::test_main_static
     let test_main_path = ecx.path(sp, vec![token::str_to_ident("test"),
                                            token::str_to_ident("test_main_static")]);
-    // ::std::env::args
-    let os_args_path = ecx.path_global(sp, vec![token::str_to_ident("std"),
-                                                token::str_to_ident("env"),
-                                                token::str_to_ident("args")]);
-    // ::std::env::args()
-    let os_args_path_expr = ecx.expr_path(os_args_path);
-    let call_os_args = ecx.expr_call(sp, os_args_path_expr, vec![]);
     // test::test_main_static(...)
     let test_main_path_expr = ecx.expr_path(test_main_path);
     let tests_ident_expr = ecx.expr_ident(sp, token::str_to_ident("TESTS"));
     let call_test_main = ecx.expr_call(sp, test_main_path_expr,
-                                       vec![call_os_args, tests_ident_expr]);
+                                       vec![tests_ident_expr]);
     let call_test_main = ecx.stmt_expr(call_test_main);
     // #![main]
     let main_meta = ecx.meta_word(sp, token::intern_and_get_ident("main"));
@@ -634,12 +627,14 @@ fn mk_test_desc_and_fn_rec(cx: &TestCtxt, test: &Test) -> P<ast::Expr> {
     let fail_expr = match test.should_panic {
         ShouldPanic::No => ecx.expr_path(should_panic_path("No")),
         ShouldPanic::Yes(ref msg) => {
-            let path = should_panic_path("Yes");
-            let arg = match *msg {
-                Some(ref msg) => ecx.expr_some(span, ecx.expr_str(span, msg.clone())),
-                None => ecx.expr_none(span),
-            };
-            ecx.expr_call(span, ecx.expr_path(path), vec![arg])
+            match *msg {
+                Some(ref msg) => {
+                    let msg = ecx.expr_str(span, msg.clone());
+                    let path = should_panic_path("YesWithMessage");
+                    ecx.expr_call(span, ecx.expr_path(path), vec![msg])
+                }
+                None => ecx.expr_path(should_panic_path("Yes")),
+            }
         }
     };
 

src/libtest/lib.rs

@@ -197,7 +197,8 @@ pub struct Bencher {
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
 pub enum ShouldPanic {
     No,
-    Yes(Option<&'static str>)
+    Yes,
+    YesWithMessage(&'static str)
 }
 
 // The definition of a single test. A test runner will run a list of
@@ -262,8 +263,8 @@ pub fn test_main(args: &[String], tests: Vec<TestDescAndFn> ) {
 // a Vec<TestDescAndFn> is used in order to effect ownership-transfer
 // semantics into parallel test runners, which in turn requires a Vec<>
 // rather than a &[].
-pub fn test_main_static(args: env::Args, tests: &[TestDescAndFn]) {
-    let args = args.collect::<Vec<_>>();
+pub fn test_main_static(tests: &[TestDescAndFn]) {
+    let args = env::args().collect::<Vec<_>>();
     let owned_tests = tests.iter().map(|t| {
         match t.testfn {
             StaticTestFn(f) => TestDescAndFn { testfn: StaticTestFn(f), desc: t.desc.clone() },
@@ -1027,8 +1028,8 @@ pub fn run_test(opts: &TestOpts,
 fn calc_result(desc: &TestDesc, task_result: Result<(), Box<Any+Send>>) -> TestResult {
     match (&desc.should_panic, task_result) {
         (&ShouldPanic::No, Ok(())) |
-        (&ShouldPanic::Yes(None), Err(_)) => TrOk,
-        (&ShouldPanic::Yes(Some(msg)), Err(ref err))
+        (&ShouldPanic::Yes, Err(_)) => TrOk,
+        (&ShouldPanic::YesWithMessage(msg), Err(ref err))
             if err.downcast_ref::<String>()
                 .map(|e| &**e)
                 .or_else(|| err.downcast_ref::<&'static str>().map(|e| *e))
@@ -1276,7 +1277,7 @@ mod tests {
             desc: TestDesc {
                 name: StaticTestName("whatever"),
                 ignore: false,
-                should_panic: ShouldPanic::Yes(None)
+                should_panic: ShouldPanic::Yes,
             },
             testfn: DynTestFn(Box::new(move|| f())),
         };
@@ -1293,7 +1294,7 @@ mod tests {
             desc: TestDesc {
                 name: StaticTestName("whatever"),
                 ignore: false,
-                should_panic: ShouldPanic::Yes(Some("error message"))
+                should_panic: ShouldPanic::YesWithMessage("error message"),
             },
             testfn: DynTestFn(Box::new(move|| f())),
         };
@@ -1310,7 +1311,7 @@ mod tests {
             desc: TestDesc {
                 name: StaticTestName("whatever"),
                 ignore: false,
-                should_panic: ShouldPanic::Yes(Some("foobar"))
+                should_panic: ShouldPanic::YesWithMessage("foobar"),
             },
             testfn: DynTestFn(Box::new(move|| f())),
         };
@@ -1327,7 +1328,7 @@ mod tests {
             desc: TestDesc {
                 name: StaticTestName("whatever"),
                 ignore: false,
-                should_panic: ShouldPanic::Yes(None)
+                should_panic: ShouldPanic::Yes,
             },
             testfn: DynTestFn(Box::new(move|| f())),
         };