Rollup merge of rust-lang#61545 - flip1995:internal_lints, r=oli-obk

Implement another internal lints

cc rust-lang#49509

This adds ~~two~~ one internal lint~~s~~:
1. LINT_PASS_IMPL_WITHOUT_MACRO: Make sure, that the `{declare,impl}_lint_pass` macro is used to implement lint passes. cc rust-lang#59669
2. ~~USAGE_OF_TYCTXT_AND_SPAN_ARGS: item 2 on the list in rust-lang#49509~~

~~With 2. I wasn't sure, if this lint should be applied everywhere. That means a careful review of 0955835 would be great. Also 73fb9b4 allows this lint on some functions. Should I also apply this lint there?~~

TODO (not directly relevant for review):
- [ ] rust-lang#59316 (comment) (not sure yet, if this works or how to query for `rustc_private`, since it's not in [`Features`](https://doc.rust-lang.org/nightly/nightly-rustc/syntax/feature_gate/struct.Features.html) 🤔 cc @eddyb)
- [x] rust-lang#61735 (comment)
- [x] Check explicitly for the `{declare,impl}_lint_pass!` macros

r? @oli-obk

src/bootstrap/bin/rustc.rs

@@ -306,7 +306,20 @@ fn main() {
     }
 
     // This is required for internal lints.
-    cmd.arg("-Zunstable-options");
+    if let Some(crate_name) = args.windows(2).find(|a| &*a[0] == "--crate-name") {
+        let crate_name = crate_name[1].to_string_lossy();
+        if crate_name != "rustc_version"
+            && (crate_name.starts_with("rustc")
+                || crate_name.starts_with("syntax")
+                || crate_name == "arena"
+                || crate_name == "fmt_macros")
+        {
+            cmd.arg("-Zunstable-options");
+            if stage != "0" {
+                cmd.arg("-Wrustc::internal");
+            }
+        }
+    }
 
     // Force all crates compiled by this compiler to (a) be unstable and (b)
     // allow the `rustc_private` feature to link to other unstable crates

src/libarena/lib.rs

@@ -12,7 +12,6 @@
        test(no_crate_inject, attr(deny(warnings))))]
 
 #![deny(rust_2018_idioms)]
-#![deny(internal)]
 #![deny(unused_lifetimes)]
 
 #![feature(core_intrinsics)]

src/libfmt_macros/lib.rs

@@ -9,7 +9,6 @@
        test(attr(deny(warnings))))]
 
 #![deny(rust_2018_idioms)]
-#![deny(internal)]
 #![deny(unused_lifetimes)]
 
 #![feature(nll)]

src/librustc/lib.rs

@@ -29,7 +29,6 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![deny(rust_2018_idioms)]
-#![deny(internal)]
 #![deny(unused_lifetimes)]
 
 #![feature(arbitrary_self_types)]

src/librustc/lint/context.rs

@@ -1341,6 +1341,7 @@ struct LateLintPassObjects<'a> {
     lints: &'a mut [LateLintPassObject],
 }
 
+#[cfg_attr(not(bootstrap), allow(rustc::lint_pass_impl_without_macro))]
 impl LintPass for LateLintPassObjects<'_> {
     fn name(&self) -> &'static str {
         panic!()
@@ -1510,6 +1511,7 @@ struct EarlyLintPassObjects<'a> {
     lints: &'a mut [EarlyLintPassObject],
 }
 
+#[cfg_attr(not(bootstrap), allow(rustc::lint_pass_impl_without_macro))]
 impl LintPass for EarlyLintPassObjects<'_> {
     fn name(&self) -> &'static str {
         panic!()

src/librustc/lint/internal.rs

@@ -7,11 +7,12 @@ use crate::lint::{
 };
 use errors::Applicability;
 use rustc_data_structures::fx::FxHashMap;
-use syntax::ast::Ident;
+use syntax::ast::{Ident, Item, ItemKind};
 use syntax::symbol::{sym, Symbol};
+use syntax_pos::ExpnInfo;
 
-declare_lint! {
-    pub DEFAULT_HASH_TYPES,
+declare_tool_lint! {
+    pub rustc::DEFAULT_HASH_TYPES,
     Allow,
     "forbid HashMap and HashSet and suggest the FxHash* variants"
 }
@@ -22,7 +23,7 @@ pub struct DefaultHashTypes {
 
 impl DefaultHashTypes {
     // we are allowed to use `HashMap` and `HashSet` as identifiers for implementing the lint itself
-    #[allow(internal)]
+    #[cfg_attr(not(bootstrap), allow(rustc::default_hash_types))]
     pub fn new() -> Self {
         let mut map = FxHashMap::default();
         map.insert(sym::HashMap, sym::FxHashMap);
@@ -36,40 +37,34 @@ impl_lint_pass!(DefaultHashTypes => [DEFAULT_HASH_TYPES]);
 impl EarlyLintPass for DefaultHashTypes {
     fn check_ident(&mut self, cx: &EarlyContext<'_>, ident: Ident) {
         if let Some(replace) = self.map.get(&ident.name) {
-            let msg = format!(
-                "Prefer {} over {}, it has better performance",
-                replace, ident
-            );
+            let msg = format!("Prefer {} over {}, it has better performance", replace, ident);
             let mut db = cx.struct_span_lint(DEFAULT_HASH_TYPES, ident.span, &msg);
             db.span_suggestion(
                 ident.span,
                 "use",
                 replace.to_string(),
                 Applicability::MaybeIncorrect, // FxHashMap, ... needs another import
             );
-            db.note(&format!(
-                "a `use rustc_data_structures::fx::{}` may be necessary",
-                replace
-            ))
-            .emit();
+            db.note(&format!("a `use rustc_data_structures::fx::{}` may be necessary", replace))
+                .emit();
         }
     }
 }
 
-declare_lint! {
-    pub USAGE_OF_TY_TYKIND,
+declare_tool_lint! {
+    pub rustc::USAGE_OF_TY_TYKIND,
     Allow,
     "usage of `ty::TyKind` outside of the `ty::sty` module"
 }
 
-declare_lint! {
-    pub TY_PASS_BY_REFERENCE,
+declare_tool_lint! {
+    pub rustc::TY_PASS_BY_REFERENCE,
     Allow,
     "passing `Ty` or `TyCtxt` by reference"
 }
 
-declare_lint! {
-    pub USAGE_OF_QUALIFIED_TY,
+declare_tool_lint! {
+    pub rustc::USAGE_OF_QUALIFIED_TY,
     Allow,
     "using `ty::{Ty,TyCtxt}` instead of importing it"
 }
@@ -137,13 +132,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TyTyKind {
                     }
                 }
             }
-            TyKind::Rptr(
-                _,
-                MutTy {
-                    ty: inner_ty,
-                    mutbl: Mutability::MutImmutable,
-                },
-            ) => {
+            TyKind::Rptr(_, MutTy { ty: inner_ty, mutbl: Mutability::MutImmutable }) => {
                 if let Some(impl_did) = cx.tcx.impl_of_method(ty.hir_id.owner_def_id()) {
                     if cx.tcx.impl_trait_ref(impl_did).is_some() {
                         return;
@@ -225,3 +214,44 @@ fn gen_args(segment: &PathSegment) -> String {
 
     String::new()
 }
+
+declare_tool_lint! {
+    pub rustc::LINT_PASS_IMPL_WITHOUT_MACRO,
+    Allow,
+    "`impl LintPass` without the `declare_lint_pass!` or `impl_lint_pass!` macros"
+}
+
+declare_lint_pass!(LintPassImpl => [LINT_PASS_IMPL_WITHOUT_MACRO]);
+
+impl EarlyLintPass for LintPassImpl {
+    fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) {
+        if let ItemKind::Impl(_, _, _, _, Some(lint_pass), _, _) = &item.node {
+            if let Some(last) = lint_pass.path.segments.last() {
+                if last.ident.name == sym::LintPass {
+                    match &lint_pass.path.span.ctxt().outer_expn_info() {
+                        Some(info) if is_lint_pass_expansion(info) => {}
+                        _ => {
+                            cx.struct_span_lint(
+                                LINT_PASS_IMPL_WITHOUT_MACRO,
+                                lint_pass.path.span,
+                                "implementing `LintPass` by hand",
+                            )
+                            .help("try using `declare_lint_pass!` or `impl_lint_pass!` instead")
+                            .emit();
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+fn is_lint_pass_expansion(expn_info: &ExpnInfo) -> bool {
+    if expn_info.format.name() == sym::impl_lint_pass {
+        true
+    } else if let Some(info) = expn_info.call_site.ctxt().outer_expn_info() {
+        info.format.name() == sym::declare_lint_pass
+    } else {
+        false
+    }
+}

src/librustc/ty/codec.rs

@@ -27,6 +27,7 @@ pub trait EncodableWithShorthand: Clone + Eq + Hash {
     fn variant(&self) -> &Self::Variant;
 }
 
+#[cfg_attr(not(bootstrap), allow(rustc::usage_of_ty_tykind))]
 impl<'tcx> EncodableWithShorthand for Ty<'tcx> {
     type Variant = ty::TyKind<'tcx>;
     fn variant(&self) -> &Self::Variant {
@@ -159,6 +160,7 @@ where
     Ok(decoder.map_encoded_cnum_to_current(cnum))
 }
 
+#[cfg_attr(not(bootstrap), allow(rustc::usage_of_ty_tykind))]
 #[inline]
 pub fn decode_ty<D>(decoder: &mut D) -> Result<Ty<'tcx>, D::Error>
 where

src/librustc/ty/context.rs

@@ -130,6 +130,7 @@ impl<'tcx> CtxtInterners<'tcx> {
     }
 
     /// Intern a type
+    #[cfg_attr(not(bootstrap), allow(rustc::usage_of_ty_tykind))]
     #[inline(never)]
     fn intern_ty(&self,
         st: TyKind<'tcx>
@@ -2107,6 +2108,7 @@ impl<'tcx> Hash for Interned<'tcx, TyS<'tcx>> {
     }
 }
 
+#[cfg_attr(not(bootstrap), allow(rustc::usage_of_ty_tykind))]
 impl<'tcx> Borrow<TyKind<'tcx>> for Interned<'tcx, TyS<'tcx>> {
     fn borrow<'a>(&'a self) -> &'a TyKind<'tcx> {
         &self.0.sty
@@ -2321,6 +2323,7 @@ impl<'tcx> TyCtxt<'tcx> {
         self.mk_fn_ptr(converted_sig)
     }
 
+    #[cfg_attr(not(bootstrap), allow(rustc::usage_of_ty_tykind))]
     #[inline]
     pub fn mk_ty(&self, st: TyKind<'tcx>) -> Ty<'tcx> {
         self.interners.intern_ty(st)

src/librustc/ty/flags.rs

@@ -18,6 +18,7 @@ impl FlagComputation {
         }
     }
 
+    #[cfg_attr(not(bootstrap), allow(rustc::usage_of_ty_tykind))]
     pub fn for_sty(st: &ty::TyKind<'_>) -> FlagComputation {
         let mut result = FlagComputation::new();
         result.add_sty(st);
@@ -61,6 +62,7 @@ impl FlagComputation {
         } // otherwise, this binder captures nothing
     }
 
+    #[cfg_attr(not(bootstrap), allow(rustc::usage_of_ty_tykind))]
     fn add_sty(&mut self, st: &ty::TyKind<'_>) {
         match st {
             &ty::Bool |

src/librustc/ty/mod.rs

@@ -1,7 +1,5 @@
 // ignore-tidy-filelength
 
-#![allow(usage_of_ty_tykind)]
-
 pub use self::Variance::*;
 pub use self::AssocItemContainer::*;
 pub use self::BorrowKind::*;
@@ -484,6 +482,7 @@ bitflags! {
     }
 }
 
+#[cfg_attr(not(bootstrap), allow(rustc::usage_of_ty_tykind))]
 pub struct TyS<'tcx> {
     pub sty: TyKind<'tcx>,
     pub flags: TypeFlags,
@@ -541,29 +540,29 @@ impl<'tcx> Hash for TyS<'tcx> {
 impl<'tcx> TyS<'tcx> {
     pub fn is_primitive_ty(&self) -> bool {
         match self.sty {
-            TyKind::Bool |
-            TyKind::Char |
-            TyKind::Int(_) |
-            TyKind::Uint(_) |
-            TyKind::Float(_) |
-            TyKind::Infer(InferTy::IntVar(_)) |
-            TyKind::Infer(InferTy::FloatVar(_)) |
-            TyKind::Infer(InferTy::FreshIntTy(_)) |
-            TyKind::Infer(InferTy::FreshFloatTy(_)) => true,
-            TyKind::Ref(_, x, _) => x.is_primitive_ty(),
+            Bool |
+            Char |
+            Int(_) |
+            Uint(_) |
+            Float(_) |
+            Infer(InferTy::IntVar(_)) |
+            Infer(InferTy::FloatVar(_)) |
+            Infer(InferTy::FreshIntTy(_)) |
+            Infer(InferTy::FreshFloatTy(_)) => true,
+            Ref(_, x, _) => x.is_primitive_ty(),
             _ => false,
         }
     }
 
     pub fn is_suggestable(&self) -> bool {
         match self.sty {
-            TyKind::Opaque(..) |
-            TyKind::FnDef(..) |
-            TyKind::FnPtr(..) |
-            TyKind::Dynamic(..) |
-            TyKind::Closure(..) |
-            TyKind::Infer(..) |
-            TyKind::Projection(..) => false,
+            Opaque(..) |
+            FnDef(..) |
+            FnPtr(..) |
+            Dynamic(..) |
+            Closure(..) |
+            Infer(..) |
+            Projection(..) => false,
             _ => true,
         }
     }

src/librustc/ty/sty.rs

@@ -1,5 +1,7 @@
 //! This module contains `TyKind` and its major components.
 
+#![cfg_attr(not(bootstrap), allow(rustc::usage_of_ty_tykind))]
+
 use crate::hir;
 use crate::hir::def_id::DefId;
 use crate::infer::canonical::Canonical;

src/librustc_allocator/lib.rs

@@ -2,7 +2,6 @@
 #![feature(rustc_private)]
 
 #![deny(rust_2018_idioms)]
-#![deny(internal)]
 #![deny(unused_lifetimes)]
 
 pub mod expand;

src/librustc_borrowck/lib.rs

@@ -2,7 +2,6 @@
 
 #![allow(non_camel_case_types)]
 #![deny(rust_2018_idioms)]
-#![deny(internal)]
 #![deny(unused_lifetimes)]
 
 #![feature(in_band_lifetimes)]

src/librustc_codegen_llvm/lib.rs

@@ -23,7 +23,6 @@
 #![feature(trusted_len)]
 #![feature(mem_take)]
 #![deny(rust_2018_idioms)]
-#![deny(internal)]
 #![deny(unused_lifetimes)]
 
 use back::write::{create_target_machine, create_informational_target_machine};

src/librustc_codegen_ssa/lib.rs

@@ -14,7 +14,6 @@
 #![allow(unused_attributes)]
 #![allow(dead_code)]
 #![deny(rust_2018_idioms)]
-#![deny(internal)]
 #![deny(unused_lifetimes)]
 
 #![recursion_limit="256"]

src/librustc_codegen_utils/lib.rs

@@ -17,7 +17,6 @@
 #![recursion_limit="256"]
 
 #![deny(rust_2018_idioms)]
-#![deny(internal)]
 #![deny(unused_lifetimes)]
 
 #[macro_use]

src/librustc_data_structures/lib.rs

@@ -27,6 +27,7 @@
 #![cfg_attr(test, feature(test))]
 
 #![deny(rust_2018_idioms)]
+#![cfg_attr(not(bootstrap), allow(rustc::default_hash_types))]
 
 #[macro_use]
 extern crate log;

src/librustc_driver/lib.rs

@@ -17,7 +17,6 @@
 #![recursion_limit="256"]
 
 #![deny(rust_2018_idioms)]
-#![deny(internal)]
 #![deny(unused_lifetimes)]
 
 pub extern crate getopts;

src/librustc_errors/lib.rs

@@ -10,7 +10,6 @@
 #![feature(nll)]
 #![feature(optin_builtin_traits)]
 #![deny(rust_2018_idioms)]
-#![deny(internal)]
 #![deny(unused_lifetimes)]
 
 #[allow(unused_extern_crates)]

src/librustc_incremental/lib.rs

@@ -9,7 +9,6 @@
 #![recursion_limit="256"]
 
 #![deny(rust_2018_idioms)]
-#![deny(internal)]
 #![deny(unused_lifetimes)]
 
 #[macro_use] extern crate rustc;