Replace some aborts with Results

Fixes #31207

by removing abort_if_new_errors

Author: Nick Cameron

src/librustc/middle/resolve_lifetime.rs

@@ -93,9 +93,12 @@ type Scope<'a> = &'a ScopeChain<'a>;
 
 static ROOT_SCOPE: ScopeChain<'static> = RootScope;
 
-pub fn krate(sess: &Session, krate: &hir::Crate, def_map: &DefMap) -> NamedRegionMap {
+pub fn krate(sess: &Session,
+             krate: &hir::Crate,
+             def_map: &DefMap)
+             -> Result<NamedRegionMap, usize> {
     let mut named_region_map = NodeMap();
-    sess.abort_if_new_errors(|| {
+    try!(sess.track_errors(|| {
         krate.visit_all_items(&mut LifetimeContext {
             sess: sess,
             named_region_map: &mut named_region_map,
@@ -104,8 +107,8 @@ pub fn krate(sess: &Session, krate: &hir::Crate, def_map: &DefMap) -> NamedRegio
             trait_ref_hack: false,
             labels_in_fn: vec![],
         });
-    });
-    named_region_map
+    }));
+    Ok(named_region_map)
 }
 
 impl<'a, 'v> Visitor<'v> for LifetimeContext<'a> {

src/librustc/session/mod.rs

@@ -188,17 +188,6 @@ impl Session {
             Err(count)
         }
     }
-    pub fn abort_if_new_errors<F, T>(&self, f: F) -> T
-        where F: FnOnce() -> T
-    {
-        match self.track_errors(f) {
-            Ok(result) => result,
-            Err(_) => {
-                self.abort_if_errors();
-                unreachable!();
-            }
-        }
-    }
     pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
         self.diagnostic().span_warn(sp, msg)
     }
@@ -515,3 +504,15 @@ pub fn early_warn(output: config::ErrorOutputType, msg: &str) {
     };
     emitter.emit(None, msg, None, errors::Level::Warning);
 }
+
+// Err(0) means compilation was stopped, but no errors were found.
+// This would be better as a dedicated enum, but using try! is so convenient.
+pub type CompileResult = Result<(), usize>;
+
+pub fn compile_result_from_err_count(err_count: usize) -> CompileResult {
+    if err_count == 0 {
+        Ok(())
+    } else {
+        Err(err_count)
+    }
+}

src/librustc_driver/driver.rs

@@ -12,7 +12,7 @@ use rustc::front;
 use rustc::front::map as hir_map;
 use rustc_mir as mir;
 use rustc_mir::mir_map::MirMap;
-use rustc::session::Session;
+use rustc::session::{Session, CompileResult, compile_result_from_err_count};
 use rustc::session::config::{self, Input, OutputFilenames, OutputType};
 use rustc::session::search_paths::PathKind;
 use rustc::lint;
@@ -35,7 +35,7 @@ use rustc_plugin as plugin;
 use rustc_front::hir;
 use rustc_front::lowering::{lower_crate, LoweringContext};
 use rustc_passes::{no_asm, loops, consts, const_fn, rvalues, static_recursion};
-use super::{Compilation, CompileResult, compile_result_from_err_count};
+use super::Compilation;
 
 use serialize::json;
 
@@ -659,9 +659,9 @@ pub fn phase_2_configure_and_expand(sess: &Session,
         })
     }));
 
-    time(time_passes,
-         "const fn bodies and arguments",
-         || const_fn::check_crate(sess, &krate));
+    try!(time(time_passes,
+              "const fn bodies and arguments",
+              || const_fn::check_crate(sess, &krate)));
 
     if sess.opts.debugging_opts.input_stats {
         println!("Post-expansion node count: {}", count_nodes(&krate));
@@ -739,9 +739,11 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
              "resolution",
              || resolve::resolve_crate(sess, &hir_map, make_glob_map));
 
-    let named_region_map = time(time_passes,
-                                "lifetime resolution",
-                                || middle::resolve_lifetime::krate(sess, krate, &def_map.borrow()));
+    let named_region_map = try!(time(time_passes,
+                                     "lifetime resolution",
+                                     || middle::resolve_lifetime::krate(sess,
+                                                                        krate,
+                                                                        &def_map.borrow())));
 
     time(time_passes,
          "looking for entry point",
@@ -759,9 +761,9 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
          "loop checking",
          || loops::check_crate(sess, krate));
 
-    time(time_passes,
-         "static item recursion checking",
-         || static_recursion::check_crate(sess, krate, &def_map.borrow(), &hir_map));
+    try!(time(time_passes,
+              "static item recursion checking",
+              || static_recursion::check_crate(sess, krate, &def_map.borrow(), &hir_map)));
 
     ty::ctxt::create_and_enter(sess,
                                arenas,
@@ -774,7 +776,7 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
                                stability::Index::new(krate),
                                |tcx| {
         // passes are timed inside typeck
-        typeck::check_crate(tcx, trait_map);
+        try!(typeck::check_crate(tcx, trait_map));
 
         time(time_passes,
              "const checking",

src/librustc_driver/lib.rs

@@ -63,7 +63,7 @@ use pretty::{PpMode, UserIdentifiedItem};
 use rustc_resolve as resolve;
 use rustc_trans::back::link;
 use rustc_trans::save;
-use rustc::session::{config, Session, build_session};
+use rustc::session::{config, Session, build_session, CompileResult};
 use rustc::session::config::{Input, PrintRequest, OutputType, ErrorOutputType};
 use rustc::middle::cstore::CrateStore;
 use rustc::lint::Lint;
@@ -105,18 +105,6 @@ pub mod target_features;
 const BUG_REPORT_URL: &'static str = "https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.\
                                       md#bug-reports";
 
-// Err(0) means compilation was stopped, but no errors were found.
-// This would be better as a dedicated enum, but using try! is so convenient.
-pub type CompileResult = Result<(), usize>;
-
-pub fn compile_result_from_err_count(err_count: usize) -> CompileResult {
-    if err_count == 0 {
-        Ok(())
-    } else {
-        Err(err_count)
-    }
-}
-
 #[inline]
 fn abort_msg(err_count: usize) -> String {
     match err_count {

src/librustc_passes/const_fn.rs

@@ -11,16 +11,16 @@
 //! Verifies that const fn arguments are immutable by value bindings
 //! and the const fn body doesn't contain any statements
 
-use rustc::session::Session;
+use rustc::session::{Session, CompileResult};
 
 use syntax::ast;
 use syntax::visit::{self, Visitor, FnKind};
 use syntax::codemap::Span;
 
-pub fn check_crate(sess: &Session, krate: &ast::Crate) {
-    sess.abort_if_new_errors(|| {
+pub fn check_crate(sess: &Session, krate: &ast::Crate) -> CompileResult {
+    sess.track_errors(|| {
         visit::walk_crate(&mut CheckConstFn{ sess: sess }, krate);
-    });
+    })
 }
 
 struct CheckConstFn<'a> {

src/librustc_passes/static_recursion.rs

@@ -12,7 +12,7 @@
 // recursively.
 
 use rustc::front::map as ast_map;
-use rustc::session::Session;
+use rustc::session::{Session, CompileResult};
 use rustc::middle::def::{Def, DefMap};
 use rustc::util::nodemap::NodeMap;
 
@@ -92,16 +92,16 @@ impl<'a, 'ast: 'a> Visitor<'ast> for CheckCrateVisitor<'a, 'ast> {
 pub fn check_crate<'ast>(sess: &Session,
                          krate: &'ast hir::Crate,
                          def_map: &DefMap,
-                         ast_map: &ast_map::Map<'ast>) {
+                         ast_map: &ast_map::Map<'ast>) -> CompileResult {
     let mut visitor = CheckCrateVisitor {
         sess: sess,
         def_map: def_map,
         ast_map: ast_map,
         discriminant_map: RefCell::new(NodeMap()),
     };
-    sess.abort_if_new_errors(|| {
+    sess.track_errors(|| {
         krate.visit_all_items(&mut visitor);
-    });
+    })
 }
 
 struct CheckItemRecursionVisitor<'a, 'ast: 'a> {

src/librustc_typeck/check/mod.rs

@@ -105,7 +105,7 @@ use middle::ty::fold::{TypeFolder, TypeFoldable};
 use middle::ty::util::Representability;
 use require_c_abi_if_variadic;
 use rscope::{ElisionFailureInfo, RegionScope};
-use session::Session;
+use session::{Session, CompileResult};
 use {CrateCtxt, lookup_full_def};
 use TypeAndSubsts;
 use lint;
@@ -383,29 +383,29 @@ impl<'a, 'tcx> Visitor<'tcx> for CheckItemBodiesVisitor<'a, 'tcx> {
     }
 }
 
-pub fn check_wf_new(ccx: &CrateCtxt) {
-    ccx.tcx.sess.abort_if_new_errors(|| {
+pub fn check_wf_new(ccx: &CrateCtxt) -> CompileResult {
+    ccx.tcx.sess.track_errors(|| {
         let mut visit = wfcheck::CheckTypeWellFormedVisitor::new(ccx);
         ccx.tcx.visit_all_items_in_krate(DepNode::WfCheck, &mut visit);
-    });
+    })
 }
 
-pub fn check_item_types(ccx: &CrateCtxt) {
-    ccx.tcx.sess.abort_if_new_errors(|| {
+pub fn check_item_types(ccx: &CrateCtxt) -> CompileResult {
+    ccx.tcx.sess.track_errors(|| {
         let mut visit = CheckItemTypesVisitor { ccx: ccx };
         ccx.tcx.visit_all_items_in_krate(DepNode::TypeckItemType, &mut visit);
-    });
+    })
 }
 
-pub fn check_item_bodies(ccx: &CrateCtxt) {
-    ccx.tcx.sess.abort_if_new_errors(|| {
+pub fn check_item_bodies(ccx: &CrateCtxt) -> CompileResult {
+    ccx.tcx.sess.track_errors(|| {
         let mut visit = CheckItemBodiesVisitor { ccx: ccx };
         ccx.tcx.visit_all_items_in_krate(DepNode::TypeckItemBody, &mut visit);
-    });
+    })
 }
 
-pub fn check_drop_impls(ccx: &CrateCtxt) {
-    ccx.tcx.sess.abort_if_new_errors(|| {
+pub fn check_drop_impls(ccx: &CrateCtxt) -> CompileResult {
+    ccx.tcx.sess.track_errors(|| {
         let _task = ccx.tcx.dep_graph.in_task(DepNode::Dropck);
         let drop_trait = match ccx.tcx.lang_items.drop_trait() {
             Some(id) => ccx.tcx.lookup_trait_def(id), None => { return }
@@ -421,7 +421,7 @@ pub fn check_drop_impls(ccx: &CrateCtxt) {
                 }
             }
         });
-    });
+    })
 }
 
 fn check_bare_fn<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,

src/librustc_typeck/lib.rs

@@ -105,7 +105,7 @@ use middle::def::Def;
 use middle::infer::{self, TypeOrigin};
 use middle::subst;
 use middle::ty::{self, Ty, TypeFoldable};
-use session::config;
+use session::{config, CompileResult};
 use util::common::time;
 use rustc_front::hir;
 
@@ -323,7 +323,7 @@ fn check_for_entry_fn(ccx: &CrateCtxt) {
     }
 }
 
-pub fn check_crate(tcx: &ty::ctxt, trait_map: ty::TraitMap) {
+pub fn check_crate(tcx: &ty::ctxt, trait_map: ty::TraitMap) -> CompileResult {
     let time_passes = tcx.sess.time_passes();
     let ccx = CrateCtxt {
         trait_map: trait_map,
@@ -333,34 +333,40 @@ pub fn check_crate(tcx: &ty::ctxt, trait_map: ty::TraitMap) {
 
     // this ensures that later parts of type checking can assume that items
     // have valid types and not error
-    tcx.sess.abort_if_new_errors(|| {
+    try!(tcx.sess.track_errors(|| {
         time(time_passes, "type collecting", ||
              collect::collect_item_types(tcx));
 
-    });
+    }));
 
     time(time_passes, "variance inference", ||
          variance::infer_variance(tcx));
 
-    tcx.sess.abort_if_new_errors(|| {
+    try!(tcx.sess.track_errors(|| {
       time(time_passes, "coherence checking", ||
           coherence::check_coherence(&ccx));
-    });
+    }));
 
-    time(time_passes, "wf checking", ||
-        check::check_wf_new(&ccx));
+    try!(time(time_passes, "wf checking", ||
+        check::check_wf_new(&ccx)));
 
-    time(time_passes, "item-types checking", ||
-        check::check_item_types(&ccx));
+    try!(time(time_passes, "item-types checking", ||
+        check::check_item_types(&ccx)));
 
-    time(time_passes, "item-bodies checking", ||
-        check::check_item_bodies(&ccx));
+    try!(time(time_passes, "item-bodies checking", ||
+        check::check_item_bodies(&ccx)));
 
-    time(time_passes, "drop-impl checking", ||
-        check::check_drop_impls(&ccx));
+    try!(time(time_passes, "drop-impl checking", ||
+        check::check_drop_impls(&ccx)));
 
     check_for_entry_fn(&ccx);
-    tcx.sess.abort_if_errors();
+
+    let err_count = tcx.sess.err_count();
+    if err_count == 0 {
+        Ok(())
+    } else {
+        Err(err_count)
+    }
 }
 
 __build_diagnostic_array! { librustc_typeck, DIAGNOSTICS }

src/libsyntax/parse/parser.rs

@@ -2483,8 +2483,7 @@ impl<'a> Parser<'a> {
                                     float.trunc() as usize,
                                     format!(".{}", fstr.splitn(2, ".").last().unwrap())));
                     }
-                    err.emit();
-                    self.abort_if_errors();
+                    return Err(err);
 
                   }
                   _ => {
@@ -4117,9 +4116,7 @@ impl<'a> Parser<'a> {
                               or did you mean the comma-separated arguments \
                               'a, Type?");
             err.span_note(mk_sp(span_lo, span_hi), &msg);
-            err.emit();
-
-            self.abort_if_errors()
+            return Err(err);
         }
 
         // First parse types.
@@ -5189,8 +5186,7 @@ impl<'a> Parser<'a> {
                                         of possibly redeclaring it",
                                        paths.name));
             }
-            err.emit();
-            self.abort_if_errors();
+            return Err(err);
         }
 
         match paths.result {