Auto merge of #48615 - Manishearth:rollup, r=Manishearth

Rollup of 10 pull requests

- Successful merges: #48355, #48359, #48380, #48419, #48420, #48461, #48522, #48570, #48572, #48603
- Failed merges:

Author: bors

Diff for: src/doc/man/rustc.1

@@ -125,6 +125,16 @@ Print version info and exit.
 \fB\-v\fR, \fB\-\-verbose\fR
 Use verbose output.
 .TP
+\fB\-\-remap\-path\-prefix\fR \fIfrom\fR=\fIto\fR
+Remap source path prefixes in all output, including compiler diagnostics, debug information,
+macro expansions, etc. The \fIfrom\fR=\fIto\fR parameter is scanned from right to left, so \fIfrom\fR
+may contain '=', but \fIto\fR may not.
+
+This is useful for normalizing build products, for example by removing the current directory out of
+pathnames emitted into the object files. The replacement is purely textual, with no consideration of
+the current system's pathname syntax. For example \fI\-\-remap\-path\-prefix foo=bar\fR will
+match \fBfoo/lib.rs\fR but not \fB./foo/lib.rs\fR.
+.TP
 \fB\-\-extern\fR \fINAME\fR=\fIPATH\fR
 Specify where an external rust library is located. These should match
 \fIextern\fR declarations in the crate's source code.

Diff for: src/doc/unstable-book/src/compiler-flags/remap-path-prefix.md

@@ -1062,8 +1062,8 @@ pub trait Iterator {
     /// assert_eq!(merged, "alphabetagamma");
     /// ```
     ///
-    /// You can also rewrite this in terms of [`flat_map()`] which is preferable
-    /// in this case since that conveys intent clearer:
+    /// You can also rewrite this in terms of [`flat_map()`], which is preferable
+    /// in this case since it conveys intent more clearly:
     ///
     /// ```
     /// let words = ["alpha", "beta", "gamma"];

Diff for: src/libcore/iter/iterator.rs

@@ -64,7 +64,8 @@ pub fn panic_fmt(fmt: fmt::Arguments, file_line_col: &(&'static str, u32, u32))
     #[allow(improper_ctypes)]
     extern {
         #[lang = "panic_fmt"]
-        #[unwind]
+        #[cfg_attr(stage0, unwind)]
+        #[cfg_attr(not(stage0), unwind(allowed))]
         fn panic_impl(fmt: fmt::Arguments, file: &'static str, line: u32, col: u32) -> !;
     }
     let (file, line, col) = *file_line_col;

Diff for: src/libcore/panicking.rs

@@ -286,7 +286,8 @@ unsafe fn find_eh_action(context: *mut uw::_Unwind_Context)
 // See docs in the `unwind` module.
 #[cfg(all(target_os="windows", target_arch = "x86", target_env="gnu"))]
 #[lang = "eh_unwind_resume"]
-#[unwind]
+#[cfg_attr(stage0, unwind)]
+#[cfg_attr(not(stage0), unwind(allowed))]
 unsafe extern "C" fn rust_eh_unwind_resume(panic_ctx: *mut u8) -> ! {
     uw::_Unwind_Resume(panic_ctx as *mut uw::_Unwind_Exception);
 }

Diff for: src/libpanic_unwind/gcc.rs

@@ -112,7 +112,8 @@ pub unsafe extern "C" fn __rust_maybe_catch_panic(f: fn(*mut u8),
 // Entry point for raising an exception, just delegates to the platform-specific
 // implementation.
 #[no_mangle]
-#[unwind]
+#[cfg_attr(stage0, unwind)]
+#[cfg_attr(not(stage0), unwind(allowed))]
 pub unsafe extern "C" fn __rust_start_panic(data: usize, vtable: usize) -> u32 {
     imp::panic(mem::transmute(raw::TraitObject {
         data: data as *mut (),

Diff for: src/libpanic_unwind/lib.rs

@@ -108,7 +108,8 @@ unsafe extern "C" fn rust_eh_personality(exceptionRecord: *mut c::EXCEPTION_RECO
 }
 
 #[lang = "eh_unwind_resume"]
-#[unwind]
+#[cfg_attr(stage0, unwind)]
+#[cfg_attr(not(stage0), unwind(allowed))]
 unsafe extern "C" fn rust_eh_unwind_resume(panic_ctx: c::LPVOID) -> ! {
     let params = [panic_ctx as c::ULONG_PTR];
     c::RaiseException(RUST_PANIC,

Diff for: src/libpanic_unwind/seh64_gnu.rs

@@ -79,18 +79,21 @@ pub enum EXCEPTION_DISPOSITION {
 pub use self::EXCEPTION_DISPOSITION::*;
 
 extern "system" {
-    #[unwind]
+    #[cfg_attr(stage0, unwind)]
+    #[cfg_attr(not(stage0), unwind(allowed))]
     pub fn RaiseException(dwExceptionCode: DWORD,
                           dwExceptionFlags: DWORD,
                           nNumberOfArguments: DWORD,
                           lpArguments: *const ULONG_PTR);
-    #[unwind]
+    #[cfg_attr(stage0, unwind)]
+    #[cfg_attr(not(stage0), unwind(allowed))]
     pub fn RtlUnwindEx(TargetFrame: LPVOID,
                        TargetIp: LPVOID,
                        ExceptionRecord: *const EXCEPTION_RECORD,
                        ReturnValue: LPVOID,
                        OriginalContext: *const CONTEXT,
                        HistoryTable: *const UNWIND_HISTORY_TABLE);
-    #[unwind]
+    #[cfg_attr(stage0, unwind)]
+    #[cfg_attr(not(stage0), unwind(allowed))]
     pub fn _CxxThrowException(pExceptionObject: *mut c_void, pThrowInfo: *mut u8);
 }

Diff for: src/libpanic_unwind/windows.rs

@@ -316,7 +316,7 @@ impl SourceFile {
     /// If the code span associated with this `SourceFile` was generated by an external macro, this
     /// may not be an actual path on the filesystem. Use [`is_real`] to check.
     ///
-    /// Also note that even if `is_real` returns `true`, if `-Z remap-path-prefix-*` was passed on
+    /// Also note that even if `is_real` returns `true`, if `--remap-path-prefix` was passed on
     /// the command line, the path as given may not actually be valid.
     ///
     /// [`is_real`]: #method.is_real

Diff for: src/libproc_macro/lib.rs

@@ -46,7 +46,7 @@ use hir::HirVec;
 use hir::map::{Definitions, DefKey, DefPathData};
 use hir::def_id::{DefIndex, DefId, CRATE_DEF_INDEX, DefIndexAddressSpace};
 use hir::def::{Def, PathResolution};
-use lint::builtin::PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES;
+use lint::builtin::{self, PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES};
 use middle::cstore::CrateStore;
 use rustc_data_structures::indexed_vec::IndexVec;
 use session::Session;
@@ -912,7 +912,11 @@ impl<'a> LoweringContext<'a> {
             TyKind::Path(ref qself, ref path) => {
                 let id = self.lower_node_id(t.id);
                 let qpath = self.lower_qpath(t.id, qself, path, ParamMode::Explicit, itctx);
-                return self.ty_path(id, t.span, qpath);
+                let ty = self.ty_path(id, t.span, qpath);
+                if let hir::TyTraitObject(..) = ty.node {
+                    self.maybe_lint_bare_trait(t.span, t.id, qself.is_none() && path.is_global());
+                }
+                return ty;
             }
             TyKind::ImplicitSelf => {
                 hir::TyPath(hir::QPath::Resolved(None, P(hir::Path {
@@ -931,7 +935,7 @@ impl<'a> LoweringContext<'a> {
                 let expr = self.lower_body(None, |this| this.lower_expr(expr));
                 hir::TyTypeof(expr)
             }
-            TyKind::TraitObject(ref bounds, ..) => {
+            TyKind::TraitObject(ref bounds, kind) => {
                 let mut lifetime_bound = None;
                 let bounds = bounds.iter().filter_map(|bound| {
                     match *bound {
@@ -950,6 +954,9 @@ impl<'a> LoweringContext<'a> {
                 let lifetime_bound = lifetime_bound.unwrap_or_else(|| {
                     self.elided_lifetime(t.span)
                 });
+                if kind != TraitObjectSyntax::Dyn {
+                    self.maybe_lint_bare_trait(t.span, t.id, false);
+                }
                 hir::TyTraitObject(bounds, lifetime_bound)
             }
             TyKind::ImplTrait(ref bounds) => {
@@ -3685,7 +3692,6 @@ impl<'a> LoweringContext<'a> {
                     // The original ID is taken by the `PolyTraitRef`,
                     // so the `Ty` itself needs a different one.
                     id = self.next_id();
-
                     hir::TyTraitObject(hir_vec![principal], self.elided_lifetime(span))
                 } else {
                     hir::TyPath(hir::QPath::Resolved(None, path))
@@ -3703,6 +3709,16 @@ impl<'a> LoweringContext<'a> {
             name: hir::LifetimeName::Implicit,
         }
     }
+
+    fn maybe_lint_bare_trait(&self, span: Span, id: NodeId, is_global: bool) {
+        if self.sess.features.borrow().dyn_trait {
+            self.sess.buffer_lint_with_diagnostic(
+                builtin::BARE_TRAIT_OBJECT, id, span,
+                "trait objects without an explicit `dyn` are deprecated",
+                builtin::BuiltinLintDiagnostics::BareTraitObject(span, is_global)
+            )
+        }
+    }
 }
 
 fn body_ids(bodies: &BTreeMap<hir::BodyId, hir::Body>) -> Vec<hir::BodyId> {

Diff for: src/librustc/hir/lowering.rs

@@ -41,6 +41,8 @@
        html_root_url = "https://doc.rust-lang.org/nightly/")]
 #![deny(warnings)]
 
+#![cfg_attr(not(stage0), allow(bare_trait_object))]
+
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(conservative_impl_trait)]

Diff for: src/librustc/lib.rs

@@ -14,7 +14,11 @@
 //! compiler code, rather than using their own custom pass. Those
 //! lints are all available in `rustc_lint::builtin`.
 
+use errors::DiagnosticBuilder;
 use lint::{LintPass, LateLintPass, LintArray};
+use session::Session;
+use session::config::Epoch;
+use syntax::codemap::Span;
 
 declare_lint! {
     pub CONST_ERR,
@@ -252,6 +256,13 @@ declare_lint! {
     "hidden lifetime parameters are deprecated, try `Foo<'_>`"
 }
 
+declare_lint! {
+    pub BARE_TRAIT_OBJECT,
+    Warn,
+    "suggest using `dyn Trait` for trait objects",
+    Epoch::Epoch2018
+}
+
 /// Does nothing as a lint pass, but registers some `Lint`s
 /// which are used by other parts of the compiler.
 #[derive(Copy, Clone)]
@@ -298,10 +309,34 @@ impl LintPass for HardwiredLints {
             COERCE_NEVER,
             SINGLE_USE_LIFETIME,
             TYVAR_BEHIND_RAW_POINTER,
-            ELIDED_LIFETIME_IN_PATH
-
+            ELIDED_LIFETIME_IN_PATH,
+            BARE_TRAIT_OBJECT
         )
     }
 }
 
+// this could be a closure, but then implementing derive traits
+// becomes hacky (and it gets allocated)
+#[derive(PartialEq, RustcEncodable, RustcDecodable, Debug)]
+pub enum BuiltinLintDiagnostics {
+    Normal,
+    BareTraitObject(Span, /* is_global */ bool)
+}
+
+impl BuiltinLintDiagnostics {
+    pub fn run(self, sess: &Session, db: &mut DiagnosticBuilder) {
+        match self {
+            BuiltinLintDiagnostics::Normal => (),
+            BuiltinLintDiagnostics::BareTraitObject(span, is_global) => {
+                let sugg = match sess.codemap().span_to_snippet(span) {
+                    Ok(ref s) if is_global => format!("dyn ({})", s),
+                    Ok(s) => format!("dyn {}", s),
+                    Err(_) => format!("dyn <type>")
+                };
+                db.span_suggestion(span, "use `dyn`", sugg);
+            }
+        }
+    }
+}
+
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for HardwiredLints {}

Diff for: src/librustc/lint/builtin.rs

@@ -29,6 +29,7 @@ use self::TargetLint::*;
 use std::slice;
 use lint::{EarlyLintPassObject, LateLintPassObject};
 use lint::{Level, Lint, LintId, LintPass, LintBuffer};
+use lint::builtin::BuiltinLintDiagnostics;
 use lint::levels::{LintLevelSets, LintLevelsBuilder};
 use middle::privacy::AccessLevels;
 use rustc_serialize::{Decoder, Decodable, Encoder, Encodable};
@@ -92,14 +93,19 @@ pub struct BufferedEarlyLint {
     pub ast_id: ast::NodeId,
     pub span: MultiSpan,
     pub msg: String,
+    pub diagnostic: BuiltinLintDiagnostics,
 }
 
 /// Extra information for a future incompatibility lint. See the call
 /// to `register_future_incompatible` in `librustc_lint/lib.rs` for
 /// guidelines.
 pub struct FutureIncompatibleInfo {
     pub id: LintId,
-    pub reference: &'static str // e.g., a URL for an issue/PR/RFC or error code
+    /// e.g., a URL for an issue/PR/RFC or error code
+    pub reference: &'static str,
+    /// If this is an epoch fixing lint, the epoch in which
+    /// this lint becomes obsolete
+    pub epoch: Option<config::Epoch>,
 }
 
 /// The target of the `by_name` map, which accounts for renaming/deprecation.
@@ -194,11 +200,24 @@ impl LintStore {
     pub fn register_future_incompatible(&mut self,
                                         sess: Option<&Session>,
                                         lints: Vec<FutureIncompatibleInfo>) {
-        let ids = lints.iter().map(|f| f.id).collect();
-        self.register_group(sess, false, "future_incompatible", ids);
-        for info in lints {
-            self.future_incompatible.insert(info.id, info);
+
+        for epoch in config::ALL_EPOCHS {
+            let lints = lints.iter().filter(|f| f.epoch == Some(*epoch)).map(|f| f.id)
+                             .collect::<Vec<_>>();
+            if !lints.is_empty() {
+                self.register_group(sess, false, epoch.lint_name(), lints)
+            }
         }
+
+        let mut future_incompatible = vec![];
+        for lint in lints {
+            future_incompatible.push(lint.id);
+            self.future_incompatible.insert(lint.id, lint);
+        }
+
+        self.register_group(sess, false, "future_incompatible", future_incompatible);
+
+
     }
 
     pub fn future_incompatible(&self, id: LintId) -> Option<&FutureIncompatibleInfo> {
@@ -429,6 +448,16 @@ pub trait LintContext<'tcx>: Sized {
         self.lookup(lint, span, msg).emit();
     }
 
+    fn lookup_and_emit_with_diagnostics<S: Into<MultiSpan>>(&self,
+                                                            lint: &'static Lint,
+                                                            span: Option<S>,
+                                                            msg: &str,
+                                                            diagnostic: BuiltinLintDiagnostics) {
+        let mut db = self.lookup(lint, span, msg);
+        diagnostic.run(self.sess(), &mut db);
+        db.emit();
+    }
+
     fn lookup<S: Into<MultiSpan>>(&self,
                                   lint: &'static Lint,
                                   span: Option<S>,
@@ -499,9 +528,10 @@ impl<'a> EarlyContext<'a> {
 
     fn check_id(&mut self, id: ast::NodeId) {
         for early_lint in self.buffered.take(id) {
-            self.lookup_and_emit(early_lint.lint_id.lint,
-                                 Some(early_lint.span.clone()),
-                                 &early_lint.msg);
+            self.lookup_and_emit_with_diagnostics(early_lint.lint_id.lint,
+                                                  Some(early_lint.span.clone()),
+                                                  &early_lint.msg,
+                                                  early_lint.diagnostic);
         }
     }
 }
@@ -1054,7 +1084,7 @@ pub fn check_ast_crate(sess: &Session, krate: &ast::Crate) {
     if !sess.opts.actually_rustdoc {
         for (_id, lints) in cx.buffered.map {
             for early_lint in lints {
-                span_bug!(early_lint.span, "failed to process buffered lint here");
+                sess.delay_span_bug(early_lint.span, "failed to process buffered lint here");
             }
         }
     }