Auto merge of #42894 - petrochenkov:deny, r=nikomatsakis

Make sufficiently old or low-impact compatibility lints deny-by-default

Needs crater run before proceeding.

r? @nikomatsakis

Author: bors

src/librustc/diagnostics.rs

@@ -614,7 +614,7 @@ use std::mem::transmute;
 struct Foo<T>(Vec<T>);
 
 trait MyTransmutableType: Sized {
-    fn transmute(Vec<Self>) -> Foo<Self>;
+    fn transmute(_: Vec<Self>) -> Foo<Self>;
 }
 
 impl MyTransmutableType for u8 {

src/librustc/lint/builtin.rs

@@ -130,6 +130,12 @@ declare_lint! {
     "detect private items in public interfaces not caught by the old implementation"
 }
 
+declare_lint! {
+    pub PUB_USE_OF_PRIVATE_EXTERN_CRATE,
+    Deny,
+    "detect public reexports of private extern crates"
+}
+
 declare_lint! {
     pub INVALID_TYPE_PARAM_DEFAULT,
     Deny,
@@ -144,14 +150,14 @@ declare_lint! {
 
 declare_lint! {
     pub RESOLVE_TRAIT_ON_DEFAULTED_UNIT,
-    Warn,
+    Deny,
     "attempt to resolve a trait on an expression whose type cannot be inferred but which \
      currently defaults to ()"
 }
 
 declare_lint! {
     pub SAFE_EXTERN_STATICS,
-    Warn,
+    Deny,
     "safe access to extern statics was erroneously allowed"
 }
 
@@ -169,14 +175,14 @@ declare_lint! {
 
 declare_lint! {
     pub LEGACY_DIRECTORY_OWNERSHIP,
-    Warn,
+    Deny,
     "non-inline, non-`#[path]` modules (e.g. `mod foo;`) were erroneously allowed in some files \
      not named `mod.rs`"
 }
 
 declare_lint! {
     pub LEGACY_IMPORTS,
-    Warn,
+    Deny,
     "detects names that resolve to ambiguous glob imports with RFC 1560"
 }
 
@@ -188,13 +194,13 @@ declare_lint! {
 
 declare_lint! {
     pub MISSING_FRAGMENT_SPECIFIER,
-    Warn,
+    Deny,
     "detects missing fragment specifiers in unused `macro_rules!` patterns"
 }
 
 declare_lint! {
     pub PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES,
-    Warn,
+    Deny,
     "detects parenthesized generic parameters in type and module names"
 }
 
@@ -230,6 +236,7 @@ impl LintPass for HardwiredLints {
             TRIVIAL_CASTS,
             TRIVIAL_NUMERIC_CASTS,
             PRIVATE_IN_PUBLIC,
+            PUB_USE_OF_PRIVATE_EXTERN_CRATE,
             INVALID_TYPE_PARAM_DEFAULT,
             CONST_ERR,
             RENAMED_AND_REMOVED_LINTS,

src/librustc_lint/lib.rs

@@ -184,6 +184,10 @@ pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
             id: LintId::of(PRIVATE_IN_PUBLIC),
             reference: "issue #34537 <https://github.com/rust-lang/rust/issues/34537>",
         },
+        FutureIncompatibleInfo {
+            id: LintId::of(PUB_USE_OF_PRIVATE_EXTERN_CRATE),
+            reference: "issue #34537 <https://github.com/rust-lang/rust/issues/34537>",
+        },
         FutureIncompatibleInfo {
             id: LintId::of(PATTERNS_IN_FNS_WITHOUT_BODY),
             reference: "issue #35203 <https://github.com/rust-lang/rust/issues/35203>",

src/librustc_resolve/diagnostics.rs

@@ -837,7 +837,7 @@ impl Something {} // ok!
 trait Foo {
     type N;
 
-    fn bar(Self::N); // ok!
+    fn bar(_: Self::N); // ok!
 }
 
 // or:

src/librustc_resolve/resolve_imports.rs

@@ -18,7 +18,7 @@ use {names_to_string, module_to_string};
 use {resolve_error, ResolutionError};
 
 use rustc::ty;
-use rustc::lint::builtin::PRIVATE_IN_PUBLIC;
+use rustc::lint::builtin::PUB_USE_OF_PRIVATE_EXTERN_CRATE;
 use rustc::hir::def_id::DefId;
 use rustc::hir::def::*;
 use rustc::util::nodemap::FxHashMap;
@@ -296,7 +296,8 @@ impl<'a> Resolver<'a> {
     pub fn import(&self, binding: &'a NameBinding<'a>, directive: &'a ImportDirective<'a>)
                   -> &'a NameBinding<'a> {
         let vis = if binding.pseudo_vis().is_at_least(directive.vis.get(), self) ||
-                     !directive.is_glob() && binding.is_extern_crate() { // c.f. `PRIVATE_IN_PUBLIC`
+                     // c.f. `PUB_USE_OF_PRIVATE_EXTERN_CRATE`
+                     !directive.is_glob() && binding.is_extern_crate() {
             directive.vis.get()
         } else {
             binding.pseudo_vis()
@@ -735,7 +736,8 @@ impl<'a, 'b:'a> ImportResolver<'a, 'b> {
                 let msg = format!("extern crate `{}` is private, and cannot be reexported \
                                    (error E0365), consider declaring with `pub`",
                                    ident);
-                self.session.add_lint(PRIVATE_IN_PUBLIC, directive.id, directive.span, msg);
+                self.session.add_lint(PUB_USE_OF_PRIVATE_EXTERN_CRATE,
+                                      directive.id, directive.span, msg);
             } else if ns == TypeNS {
                 struct_span_err!(self.session, directive.span, E0365,
                                  "`{}` is private, and cannot be reexported", ident)

src/librustc_typeck/diagnostics.rs

@@ -2476,7 +2476,7 @@ trait T2 {
     type Bar;
 
     // error: Baz is used but not declared
-    fn return_bool(&self, &Self::Bar, &Self::Baz) -> bool;
+    fn return_bool(&self, _: &Self::Bar, _: &Self::Baz) -> bool;
 }
 ```
 
@@ -2498,7 +2498,7 @@ trait T2 {
     type Baz; // we declare `Baz` in our trait.
 
     // and now we can use it here:
-    fn return_bool(&self, &Self::Bar, &Self::Baz) -> bool;
+    fn return_bool(&self, _: &Self::Bar, _: &Self::Baz) -> bool;
 }
 ```
 "##,

src/test/compile-fail/associated-types-ICE-when-projecting-out-of-err.rs

@@ -25,7 +25,7 @@ pub trait Sized {
 trait Add<RHS=Self> {
     type Output;
 
-    fn add(self, RHS) -> Self::Output;
+    fn add(self, _: RHS) -> Self::Output;
 }
 
 fn ice<A>(a: A) {

src/test/compile-fail/defaulted-unit-warning.rs

@@ -8,9 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![allow(dead_code)]
-#![allow(unreachable_code)]
-#![deny(resolve_trait_on_defaulted_unit)]
+#![allow(unused)]
 
 trait Deserialize: Sized {
     fn deserialize() -> Result<Self, String>;
@@ -38,4 +36,3 @@ fn smeg() {
 fn main() {
     smeg();
 }
-

src/test/compile-fail/directory_ownership/backcompat-warnings.rs

@@ -10,12 +10,8 @@
 
 // error-pattern: cannot declare a new module at this location
 // error-pattern: will become a hard error
-// error-pattern: compilation successful
-
-#![feature(rustc_attrs)]
 
 #[path="mod_file_not_owning_aux3.rs"]
 mod foo;
 
-#[rustc_error]
 fn main() {}

src/test/compile-fail/imports/rfc-1560-warning-cycle.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(rustc_attrs)]
 #![allow(unused)]
 
 pub struct Foo;
@@ -20,12 +19,11 @@ mod bar {
         use *; //~ NOTE `Foo` could refer to the name imported here
         use bar::*; //~ NOTE `Foo` could also refer to the name imported here
         fn f(_: Foo) {}
-        //~^ WARN `Foo` is ambiguous
+        //~^ ERROR `Foo` is ambiguous
         //~| WARN hard error in a future release
         //~| NOTE see issue #38260
-        //~| NOTE #[warn(legacy_imports)] on by default
+        //~| NOTE #[deny(legacy_imports)] on by default
     }
 }
 
-#[rustc_error]
-fn main() {} //~ ERROR compilation successful
+fn main() {}