Use real try blocks

Author: taiki-e

src/librustc_mir/borrow_check/nll/mod.rs

@@ -254,14 +254,14 @@ fn dump_mir_results<'a, 'gcx, 'tcx>(
     );
 
     // Also dump the inference graph constraints as a graphviz file.
-    let _: io::Result<()> = try_block! {
+    let _: io::Result<()> = try {
         let mut file =
             pretty::create_dump_file(infcx.tcx, "regioncx.all.dot", None, "nll", &0, source)?;
         regioncx.dump_graphviz_raw_constraints(&mut file)?;
     };
 
     // Also dump the inference graph constraints as a graphviz file.
-    let _: io::Result<()> = try_block! {
+    let _: io::Result<()> = try {
         let mut file =
             pretty::create_dump_file(infcx.tcx, "regioncx.scc.dot", None, "nll", &0, source)?;
         regioncx.dump_graphviz_scc_constraints(&mut file)?;

src/librustc_mir/lib.rs

@@ -26,6 +26,7 @@ Rust MIR: a lowered representation of Rust. Also: an experiment!
 #![feature(slice_concat_ext)]
 #![feature(try_from)]
 #![feature(reverse_bits)]
+#![feature(try_blocks)]
 
 #![recursion_limit="256"]
 
@@ -43,14 +44,6 @@ extern crate serialize as rustc_serialize; // used by deriving
 #[macro_use]
 extern crate syntax;
 
-// Once we can use edition 2018 in the compiler,
-// replace this with real try blocks.
-macro_rules! try_block {
-    ($($inside:tt)*) => (
-        (||{ ::std::ops::Try::from_ok({ $($inside)* }) })()
-    )
-}
-
 mod diagnostics;
 
 mod borrow_check;

src/librustc_mir/util/pretty.rs

@@ -131,7 +131,7 @@ fn dump_matched_mir_node<'a, 'gcx, 'tcx, F>(
 ) where
     F: FnMut(PassWhere, &mut dyn Write) -> io::Result<()>,
 {
-    let _: io::Result<()> = try_block! {
+    let _: io::Result<()> = try {
         let mut file = create_dump_file(tcx, "mir", pass_num, pass_name, disambiguator, source)?;
         writeln!(file, "// MIR for `{}`", node_path)?;
         writeln!(file, "// source = {:?}", source)?;
@@ -148,7 +148,7 @@ fn dump_matched_mir_node<'a, 'gcx, 'tcx, F>(
     };
 
     if tcx.sess.opts.debugging_opts.dump_mir_graphviz {
-        let _: io::Result<()> = try_block! {
+        let _: io::Result<()> = try {
             let mut file =
                 create_dump_file(tcx, "dot", pass_num, pass_name, disambiguator, source)?;
             write_mir_fn_graphviz(tcx, source.def_id, mir, &mut file)?;