Use trybuild instead of compiletest

The compiletest crate requires lots of flaming hoops, doesn't work if
you change features between cargo runs, and currently doesn't work in
macOS at all (see Manishearth/compiletest-rs#179).

The trybuild crate, on the other hand, seems to work quite well
everywhere and gives nice diagnostics. Let's use that instead.

Cargo.toml

@@ -28,18 +28,12 @@ cache = "false"
 [features]
 default = ["std"]
 std = []
-stable = ["compiletest_rs/stable"]
-beta = ["compiletest_rs/stable"]
-nightly = ["compiletest_rs"]
 
 [package.metadata.template_ci.clippy]
 allow_failure = false
 
 [dependencies]
 
 [dev-dependencies]
+trybuild = "1.0"
 
-[dependencies.compiletest_rs]
-version = "0.4.0"
-optional = true
-features = ["tmp"]

tests/compile-fail/negative_i32.rs

@@ -5,6 +5,5 @@ use std::num::NonZeroU32;
 
 #[cfg_attr(rustfmt, rustfmt_skip)]
 fn main() {
-    let _a: NonZeroU32 = nonzero!(-2i32); //~ ERROR no method named
-    //                   ^ should not be able to convert
+    let _a: NonZeroU32 = nonzero!(-2i32);
 }

tests/compile-fail/negative_i32.stderr

@@ -0,0 +1,7 @@
+error[E0599]: no method named `as_nonzero_unchecked` found for type `i32` in the current scope
+ --> $DIR/negative_i32.rs:8:26
+  |
+8 |     let _a: NonZeroU32 = nonzero!(-2i32);
+  |                          ^^^^^^^^^^^^^^^ method not found in `i32`
+  |
+  = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)

tests/compile-fail/zero_u8.rs

@@ -5,6 +5,5 @@ use std::num::NonZeroU8;
 
 #[cfg_attr(rustfmt, rustfmt_skip)]
 fn main() {
-    let _a: NonZeroU8 = nonzero!(0u8); //~ ERROR evaluation of constant value failed [E0080]
-    //                  ^ should complain about the zero-ness of the argument
+    let _a: NonZeroU8 = nonzero!(0u8);
 }

tests/compile-fail/zero_u8.stderr

@@ -0,0 +1,7 @@
+error[E0080]: evaluation of constant value failed
+ --> $DIR/zero_u8.rs:8:25
+  |
+8 |     let _a: NonZeroU8 = nonzero!(0u8);
+  |                         ^^^^^^^^^^^^^ attempt to subtract with overflow
+  |
+  = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)

tests/compile-fail/zero_usize.rs

@@ -5,6 +5,5 @@ use std::num::NonZeroUsize;
 
 #[cfg_attr(rustfmt, rustfmt_skip)]
 fn main() {
-    let _a: NonZeroUsize = nonzero!(0usize); //~ ERROR evaluation of constant value failed [E0080]
-    //                     ^ should complain about the zero-ness of the argument
+    let _a: NonZeroUsize = nonzero!(0usize);
 }

tests/compile-fail/zero_usize.stderr

@@ -0,0 +1,7 @@
+error[E0080]: evaluation of constant value failed
+ --> $DIR/zero_usize.rs:8:28
+  |
+8 |     let _a: NonZeroUsize = nonzero!(0usize);
+  |                            ^^^^^^^^^^^^^^^^ attempt to subtract with overflow
+  |
+  = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)

tests/compiletest.rs

@@ -1,57 +1,6 @@
-#![cfg(feature = "compiletest_rs")]
-
-extern crate compiletest_rs as compiletest;
-use std::fs::{read_dir, remove_file};
-use std::path::PathBuf;
-
-fn clean_rlibs(config: &compiletest_rs::Config) {
-    if config.target_rustcflags.is_some() {
-        for directory in config
-            .target_rustcflags
-            .as_ref()
-            .unwrap()
-            .split_whitespace()
-        {
-            if let Ok(mut entries) = read_dir(directory) {
-                while let Some(Ok(entry)) = entries.next() {
-                    let f = entry.file_name().clone().into_string().unwrap();
-                    if f.ends_with(".rmeta") {
-                        let prefix = &f[..f.len() - 5];
-                        let _ = remove_file(entry.path());
-                        if let Ok(mut entries) = read_dir(directory) {
-                            while let Some(Ok(entry)) = entries.next() {
-                                let f = entry.file_name().clone().into_string().unwrap();
-                                if f.starts_with(prefix) && !f.ends_with(".rmeta") {
-                                    let _ = remove_file(entry.path());
-                                }
-                            }
-                        }
-                    }
-                }
-            }
-        }
-    }
-}
-
-fn run_mode(mode: &'static str) {
-    let mut config = compiletest::Config::default().tempdir();
-    let cfg_mode = mode.parse().expect("Invalid mode");
-
-    config.mode = cfg_mode;
-    config.src_base = PathBuf::from(format!("tests/{}", mode));
-    // config.target_rustcflags = Some("-L target/debug -L target/debug/deps".to_string());
-    config.link_deps();
-    config.clean_rmeta();
-    clean_rlibs(&config);
-
-    compiletest::run_tests(&config);
-}
-
 #[test]
 fn compile_test() {
-    // Don't run compile-fail tests under nightly: Error messages are unstable.
-    #[cfg(feature = "stable")]
-    run_mode("compile-fail");
-
-    run_mode("run-pass");
+    let t = trybuild::TestCases::new();
+    t.compile_fail("tests/compile-fail/*.rs");
+    t.pass("tests/run-pass/*.rs");
 }