Rollup of 8 pull requests

Cargo.lock

@@ -430,9 +430,9 @@ dependencies = [
 
 [[package]]
 name = "chalk-derive"
-version = "0.29.0"
+version = "0.31.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3a7f257e3bcdc56d8877ae31c012bd69fba0be66929d588e603905f2632c0c59"
+checksum = "ca40c97e20f43e4aac2282d342103d45fafad74ad9bfcbaaf0b5d386f9ce1f39"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -442,9 +442,9 @@ dependencies = [
 
 [[package]]
 name = "chalk-engine"
-version = "0.29.0"
+version = "0.31.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c43fcc7edf4d51b42f44ed50e2337bd90ddc8e088d0cd78a71db92a6f780f782"
+checksum = "88e3d545394fbc4f7d8fe203c6a78d2b73f82bb119f21af98de1f924c2518e34"
 dependencies = [
  "chalk-derive",
  "chalk-ir",
@@ -455,19 +455,19 @@ dependencies = [
 
 [[package]]
 name = "chalk-ir"
-version = "0.29.0"
+version = "0.31.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "03a4050029ecb2b5a1ff3bfc64c39279179b294821ec2e8891a4a5c6e3a08db0"
+checksum = "8c4183955e084fcc387b515f867ed0e17e9e7301f5eee29c0338d5e63315bb41"
 dependencies = [
  "chalk-derive",
  "lazy_static",
 ]
 
 [[package]]
 name = "chalk-solve"
-version = "0.29.0"
+version = "0.31.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "828c1f80d4eaf681027cce02050c54a3c97370f81988d31bf2a56df54048746c"
+checksum = "50e8407bba06d9e760011a28060e8f3b3f87b82ea53fb8bfaa43614c19c14dcc"
 dependencies = [
  "chalk-derive",
  "chalk-ir",
@@ -5064,9 +5064,9 @@ dependencies = [
 
 [[package]]
 name = "tracing-serde"
-version = "0.1.1"
+version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b6ccba2f8f16e0ed268fc765d9b7ff22e965e7185d32f8f1ec8294fe17d86e79"
+checksum = "fb65ea441fbb84f9f6748fd496cf7f63ec9af5bca94dd86456978d055e8eb28b"
 dependencies = [
  "serde",
  "tracing-core",

compiler/rustc_hir/src/target.rs

@@ -9,13 +9,13 @@ use crate::{Item, ItemKind, TraitItem, TraitItemKind};
 
 use std::fmt::{self, Display};
 
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, PartialEq, Debug)]
 pub enum MethodKind {
     Trait { body: bool },
     Inherent,
 }
 
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, PartialEq, Debug)]
 pub enum Target {
     ExternCrate,
     Use,

compiler/rustc_lint/src/levels.rs

@@ -10,6 +10,7 @@ use rustc_hir as hir;
 use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
 use rustc_hir::{intravisit, HirId};
 use rustc_middle::hir::map::Map;
+use rustc_middle::lint::LevelSource;
 use rustc_middle::lint::LintDiagnosticBuilder;
 use rustc_middle::lint::{struct_lint_level, LintLevelMap, LintLevelSets, LintSet, LintSource};
 use rustc_middle::ty::query::Providers;
@@ -95,6 +96,44 @@ impl<'s> LintLevelsBuilder<'s> {
         self.sets.list.push(LintSet::CommandLine { specs });
     }
 
+    /// Attempts to insert the `id` to `level_src` map entry. If unsuccessful
+    /// (e.g. if a forbid was already inserted on the same scope), then emits a
+    /// diagnostic with no change to `specs`.
+    fn insert_spec(
+        &mut self,
+        specs: &mut FxHashMap<LintId, LevelSource>,
+        id: LintId,
+        (level, src): LevelSource,
+    ) {
+        if let Some((old_level, old_src)) = specs.get(&id) {
+            if old_level == &Level::Forbid && level != Level::Forbid {
+                let mut diag_builder = struct_span_err!(
+                    self.sess,
+                    src.span(),
+                    E0453,
+                    "{}({}) incompatible with previous forbid in same scope",
+                    level.as_str(),
+                    src.name(),
+                );
+                match *old_src {
+                    LintSource::Default => {}
+                    LintSource::Node(_, forbid_source_span, reason) => {
+                        diag_builder.span_label(forbid_source_span, "`forbid` level set here");
+                        if let Some(rationale) = reason {
+                            diag_builder.note(&rationale.as_str());
+                        }
+                    }
+                    LintSource::CommandLine(_) => {
+                        diag_builder.note("`forbid` lint level was set on command line");
+                    }
+                }
+                diag_builder.emit();
+                return;
+            }
+        }
+        specs.insert(id, (level, src));
+    }
+
     /// Pushes a list of AST lint attributes onto this context.
     ///
     /// This function will return a `BuilderPush` object which should be passed
@@ -109,7 +148,7 @@ impl<'s> LintLevelsBuilder<'s> {
     ///   `#[allow]`
     ///
     /// Don't forget to call `pop`!
-    pub fn push(
+    pub(crate) fn push(
         &mut self,
         attrs: &[ast::Attribute],
         store: &LintStore,
@@ -221,7 +260,7 @@ impl<'s> LintLevelsBuilder<'s> {
                         let src = LintSource::Node(name, li.span(), reason);
                         for &id in ids {
                             self.check_gated_lint(id, attr.span);
-                            specs.insert(id, (level, src));
+                            self.insert_spec(&mut specs, id, (level, src));
                         }
                     }
 
@@ -235,7 +274,7 @@ impl<'s> LintLevelsBuilder<'s> {
                                     reason,
                                 );
                                 for id in ids {
-                                    specs.insert(*id, (level, src));
+                                    self.insert_spec(&mut specs, *id, (level, src));
                                 }
                             }
                             Err((Some(ids), new_lint_name)) => {
@@ -272,7 +311,7 @@ impl<'s> LintLevelsBuilder<'s> {
                                     reason,
                                 );
                                 for id in ids {
-                                    specs.insert(*id, (level, src));
+                                    self.insert_spec(&mut specs, *id, (level, src));
                                 }
                             }
                             Err((None, _)) => {

compiler/rustc_middle/Cargo.toml

@@ -26,7 +26,7 @@ rustc_index = { path = "../rustc_index" }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_ast = { path = "../rustc_ast" }
 rustc_span = { path = "../rustc_span" }
-chalk-ir = "0.29.0"
+chalk-ir = "0.31.0"
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
 measureme = "0.7.1"
 rustc_session = { path = "../rustc_session" }

compiler/rustc_middle/src/lint.rs

@@ -9,7 +9,7 @@ use rustc_session::lint::{builtin, Level, Lint, LintId};
 use rustc_session::{DiagnosticMessageId, Session};
 use rustc_span::hygiene::MacroKind;
 use rustc_span::source_map::{DesugaringKind, ExpnKind, MultiSpan};
-use rustc_span::{Span, Symbol};
+use rustc_span::{symbol, Span, Symbol, DUMMY_SP};
 
 /// How a lint level was set.
 #[derive(Clone, Copy, PartialEq, Eq, HashStable)]
@@ -25,6 +25,24 @@ pub enum LintSource {
     CommandLine(Symbol),
 }
 
+impl LintSource {
+    pub fn name(&self) -> Symbol {
+        match *self {
+            LintSource::Default => symbol::kw::Default,
+            LintSource::Node(name, _, _) => name,
+            LintSource::CommandLine(name) => name,
+        }
+    }
+
+    pub fn span(&self) -> Span {
+        match *self {
+            LintSource::Default => DUMMY_SP,
+            LintSource::Node(_, span, _) => span,
+            LintSource::CommandLine(_) => DUMMY_SP,
+        }
+    }
+}
+
 pub type LevelSource = (Level, LintSource);
 
 pub struct LintLevelSets {

compiler/rustc_passes/src/check_attr.rs

@@ -13,12 +13,14 @@ use rustc_errors::{pluralize, struct_span_err};
 use rustc_hir as hir;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
-use rustc_hir::{self, FnSig, ForeignItem, ForeignItemKind, HirId, Item, ItemKind, TraitItem};
+use rustc_hir::{
+    self, FnSig, ForeignItem, ForeignItemKind, HirId, Item, ItemKind, TraitItem, CRATE_HIR_ID,
+};
 use rustc_hir::{MethodKind, Target};
 use rustc_session::lint::builtin::{CONFLICTING_REPR_HINTS, UNUSED_ATTRIBUTES};
 use rustc_session::parse::feature_err;
-use rustc_span::symbol::sym;
-use rustc_span::Span;
+use rustc_span::symbol::{sym, Symbol};
+use rustc_span::{Span, DUMMY_SP};
 
 pub(crate) fn target_from_impl_item<'tcx>(
     tcx: TyCtxt<'tcx>,
@@ -333,6 +335,17 @@ impl CheckAttrVisitor<'tcx> {
                                 .emit();
                             return false;
                         }
+                        if CRATE_HIR_ID == hir_id {
+                            self.tcx
+                                .sess
+                                .struct_span_err(
+                                    meta.span(),
+                                    "`#![doc(alias = \"...\")]` isn't allowed as a crate \
+                                     level attribute",
+                                )
+                                .emit();
+                            return false;
+                        }
                     }
                 }
             }
@@ -808,9 +821,46 @@ fn is_c_like_enum(item: &Item<'_>) -> bool {
     }
 }
 
+fn check_invalid_crate_level_attr(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
+    const ATTRS_TO_CHECK: &[Symbol] = &[
+        sym::macro_export,
+        sym::repr,
+        sym::path,
+        sym::automatically_derived,
+        sym::start,
+        sym::main,
+    ];
+
+    for attr in attrs {
+        for attr_to_check in ATTRS_TO_CHECK {
+            if tcx.sess.check_name(attr, *attr_to_check) {
+                tcx.sess
+                    .struct_span_err(
+                        attr.span,
+                        &format!(
+                            "`{}` attribute cannot be used at crate level",
+                            attr_to_check.to_ident_string()
+                        ),
+                    )
+                    .emit();
+            }
+        }
+    }
+}
+
 fn check_mod_attrs(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
     tcx.hir()
         .visit_item_likes_in_module(module_def_id, &mut CheckAttrVisitor { tcx }.as_deep_visitor());
+    if module_def_id.is_top_level_module() {
+        CheckAttrVisitor { tcx }.check_attributes(
+            CRATE_HIR_ID,
+            tcx.hir().krate_attrs(),
+            &DUMMY_SP,
+            Target::Mod,
+            None,
+        );
+        check_invalid_crate_level_attr(tcx, tcx.hir().krate_attrs());
+    }
 }
 
 pub(crate) fn provide(providers: &mut Providers) {

compiler/rustc_passes/src/entry.rs

@@ -78,29 +78,38 @@ fn entry_fn(tcx: TyCtxt<'_>, cnum: CrateNum) -> Option<(LocalDefId, EntryFnType)
 // Beware, this is duplicated in `librustc_builtin_macros/test_harness.rs`
 // (with `ast::Item`), so make sure to keep them in sync.
 fn entry_point_type(sess: &Session, item: &Item<'_>, at_root: bool) -> EntryPointType {
-    match item.kind {
-        ItemKind::Fn(..) => {
-            if sess.contains_name(&item.attrs, sym::start) {
-                EntryPointType::Start
-            } else if sess.contains_name(&item.attrs, sym::main) {
-                EntryPointType::MainAttr
-            } else if item.ident.name == sym::main {
-                if at_root {
-                    // This is a top-level function so can be `main`.
-                    EntryPointType::MainNamed
-                } else {
-                    EntryPointType::OtherMain
-                }
-            } else {
-                EntryPointType::None
-            }
+    if sess.contains_name(&item.attrs, sym::start) {
+        EntryPointType::Start
+    } else if sess.contains_name(&item.attrs, sym::main) {
+        EntryPointType::MainAttr
+    } else if item.ident.name == sym::main {
+        if at_root {
+            // This is a top-level function so can be `main`.
+            EntryPointType::MainNamed
+        } else {
+            EntryPointType::OtherMain
         }
-        _ => EntryPointType::None,
+    } else {
+        EntryPointType::None
     }
 }
 
+fn throw_attr_err(sess: &Session, span: Span, attr: &str) {
+    sess.struct_span_err(span, &format!("`{}` attribute can only be used on functions", attr))
+        .emit();
+}
+
 fn find_item(item: &Item<'_>, ctxt: &mut EntryContext<'_, '_>, at_root: bool) {
     match entry_point_type(&ctxt.session, item, at_root) {
+        EntryPointType::None => (),
+        _ if !matches!(item.kind, ItemKind::Fn(..)) => {
+            if let Some(attr) = ctxt.session.find_by_name(item.attrs, sym::start) {
+                throw_attr_err(&ctxt.session, attr.span, "start");
+            }
+            if let Some(attr) = ctxt.session.find_by_name(item.attrs, sym::main) {
+                throw_attr_err(&ctxt.session, attr.span, "main");
+            }
+        }
         EntryPointType::MainNamed => {
             if ctxt.main_fn.is_none() {
                 ctxt.main_fn = Some((item.hir_id, item.span));
@@ -137,7 +146,6 @@ fn find_item(item: &Item<'_>, ctxt: &mut EntryContext<'_, '_>, at_root: bool) {
                     .emit();
             }
         }
-        EntryPointType::None => (),
     }
 }
 

compiler/rustc_session/src/lint/builtin.rs

@@ -518,7 +518,7 @@ declare_lint! {
     /// ### Example
     ///
     /// ```rust
-    /// #![macro_export]
+    /// #![ignore]
     /// ```
     ///
     /// {{produces}}

compiler/rustc_traits/Cargo.toml

@@ -12,9 +12,9 @@ rustc_hir = { path = "../rustc_hir" }
 rustc_index = { path = "../rustc_index" }
 rustc_ast = { path = "../rustc_ast" }
 rustc_span = { path = "../rustc_span" }
-chalk-ir = "0.29.0"
-chalk-solve = "0.29.0"
-chalk-engine = "0.29.0"
+chalk-ir = "0.31.0"
+chalk-solve = "0.31.0"
+chalk-engine = "0.31.0"
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
 rustc_infer = { path = "../rustc_infer" }
 rustc_trait_selection = { path = "../rustc_trait_selection" }