Auto merge of #53607 - GuillaumeGomez:rollup, r=GuillaumeGomez

Rollup of 10 pull requests

Successful merges:

 - #53418 (Mark some suggestions as MachineApplicable)
 - #53431 (Moved some feature gate ui tests to correct location)
 - #53442 (Update version of rls-data used with save-analysis)
 - #53504 (Set applicability for more suggestions.)
 - #53541 (Fix missing impl trait display as ret type)
 - #53544 (Point at the trait argument when using unboxed closure)
 - #53558 (Normalize source line and column numbers.)
 - #53562 (Lament the invincibility of the Turbofish)
 - #53574 (Suggest direct raw-pointer dereference)
 - #53585 (Remove super old comment on function that parses items)

Failed merges:

 - #53472 (Use FxHash{Map,Set} instead of the default Hash{Map,Set} everywhere in rustc.)
 - #53563 (use String::new() instead of String::from(""), "".to_string(), "".to_owned() or "".into())

r? @ghost

Author: bors

Diff for: src/Cargo.lock

@@ -1858,6 +1858,15 @@ dependencies = [
  "serde_derive 1.0.70 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "rls-data"
+version = "0.18.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rls-span 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "rls-rustc"
 version = "0.5.0"
@@ -2382,7 +2391,7 @@ name = "rustc_save_analysis"
 version = "0.0.0"
 dependencies = [
  "log 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "rls-data 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rls-data 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rls-span 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3286,6 +3295,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum rls-analysis 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)" = "96f84d303dcbe1c1bdd41b10867d3399c38fbdac32c4e3645cdb6dbd7f82db1d"
 "checksum rls-blacklist 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e4a9cc2545ccb7e05b355bfe047b8039a6ec12270d5f3c996b766b340a50f7d2"
 "checksum rls-data 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3dd20763e1c60ae8945384c8a8fa4ac44f8afa7b0a817511f5e8927e5d24f988"
+"checksum rls-data 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4f81e838ecff6830ed33c2907fd236f38d441c206e983a2aa29fbce99295fab9"
 "checksum rls-rustc 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "2f9dba7390427aefa953608429701e3665192ca810ba8ae09301e001b7c7bed0"
 "checksum rls-span 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5d7c7046dc6a92f2ae02ed302746db4382e75131b9ce20ce967259f6b5867a6a"
 "checksum rls-vfs 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "ecbc8541b4c341d6271eae10f869dd9d36db871afe184f5b6f9bffbd6ed0373f"

Diff for: src/libcore/ptr.rs

@@ -582,6 +582,21 @@ impl<T: ?Sized> *const T {
     ///     }
     /// }
     /// ```
+    ///
+    /// # Null-unchecked version
+    ///
+    /// If you are sure the pointer can never be null and are looking for some kind of
+    /// `as_ref_unchecked` that returns the `&T` instead of `Option<&T>, know that you can
+    /// dereference the pointer directly.
+    ///
+    /// ```
+    /// let ptr: *const u8 = &10u8 as *const u8;
+    ///
+    /// unsafe {
+    ///     let val_back = &*ptr;
+    ///     println!("We got back the value: {}!", val_back);
+    /// }
+    /// ```
     #[stable(feature = "ptr_as_ref", since = "1.9.0")]
     #[inline]
     pub unsafe fn as_ref<'a>(self) -> Option<&'a T> {
@@ -1303,6 +1318,21 @@ impl<T: ?Sized> *mut T {
     ///     }
     /// }
     /// ```
+    ///
+    /// # Null-unchecked version
+    ///
+    /// If you are sure the pointer can never be null and are looking for some kind of
+    /// `as_ref_unchecked` that returns the `&T` instead of `Option<&T>, know that you can
+    /// dereference the pointer directly.
+    ///
+    /// ```
+    /// let ptr: *mut u8 = &mut 10u8 as *mut u8;
+    ///
+    /// unsafe {
+    ///     let val_back = &*ptr;
+    ///     println!("We got back the value: {}!", val_back);
+    /// }
+    /// ```
     #[stable(feature = "ptr_as_ref", since = "1.9.0")]
     #[inline]
     pub unsafe fn as_ref<'a>(self) -> Option<&'a T> {

Diff for: src/librustc_borrowck/borrowck/gather_loans/move_error.rs

@@ -17,7 +17,7 @@ use rustc::ty;
 use rustc_mir::util::borrowck_errors::{BorrowckErrors, Origin};
 use syntax::ast;
 use syntax_pos;
-use errors::DiagnosticBuilder;
+use errors::{DiagnosticBuilder, Applicability};
 use borrowck::gather_loans::gather_moves::PatternSource;
 
 pub struct MoveErrorCollector<'tcx> {
@@ -80,9 +80,12 @@ fn report_move_errors<'a, 'tcx>(bccx: &BorrowckCtxt<'a, 'tcx>, errors: &[MoveErr
                 let initializer =
                     e.init.as_ref().expect("should have an initializer to get an error");
                 if let Ok(snippet) = bccx.tcx.sess.source_map().span_to_snippet(initializer.span) {
-                    err.span_suggestion(initializer.span,
-                                        "consider using a reference instead",
-                                        format!("&{}", snippet));
+                    err.span_suggestion_with_applicability(
+                        initializer.span,
+                        "consider using a reference instead",
+                        format!("&{}", snippet),
+                        Applicability::MaybeIncorrect // using a reference may not be the right fix
+                    );
                 }
             }
             _ => {

Diff for: src/librustc_borrowck/borrowck/unused.rs

@@ -13,6 +13,7 @@ use rustc::hir::{self, HirId};
 use rustc::lint::builtin::UNUSED_MUT;
 use rustc::ty;
 use rustc::util::nodemap::{FxHashMap, FxHashSet};
+use errors::Applicability;
 use std::slice;
 use syntax::ptr::P;
 
@@ -83,7 +84,11 @@ impl<'a, 'tcx> UnusedMutCx<'a, 'tcx> {
                                      hir_id,
                                      span,
                                      "variable does not need to be mutable")
-                .span_suggestion_short(mut_span, "remove this `mut`", "".to_owned())
+                .span_suggestion_short_with_applicability(
+                    mut_span,
+                    "remove this `mut`",
+                    "".to_owned(),
+                    Applicability::MachineApplicable)
                 .emit();
         }
     }

Diff for: src/librustc_mir/borrow_check/mod.rs

@@ -24,7 +24,7 @@ use rustc::mir::{Terminator, TerminatorKind};
 use rustc::ty::query::Providers;
 use rustc::ty::{self, ParamEnv, TyCtxt, Ty};
 
-use rustc_errors::{Diagnostic, DiagnosticBuilder, Level};
+use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, Level};
 use rustc_data_structures::graph::dominators::Dominators;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::indexed_set::IdxSetBuf;
@@ -324,7 +324,11 @@ fn do_mir_borrowck<'a, 'gcx, 'tcx>(
                 span,
                 "variable does not need to be mutable",
             );
-            err.span_suggestion_short(mut_span, "remove this `mut`", "".to_owned());
+            err.span_suggestion_short_with_applicability(
+                mut_span,
+                "remove this `mut`",
+                "".to_owned(),
+                Applicability::MachineApplicable);
 
             err.buffer(&mut mbcx.errors_buffer);
         }

Diff for: src/librustc_passes/ast_validation.rs

@@ -25,6 +25,7 @@ use syntax::symbol::keywords;
 use syntax::visit::{self, Visitor};
 use syntax_pos::Span;
 use errors;
+use errors::Applicability;
 
 struct AstValidator<'a> {
     session: &'a Session,
@@ -185,11 +186,12 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 );
                 match val.node {
                     ExprKind::Lit(ref v) if v.node.is_numeric() => {
-                        err.span_suggestion(
+                        err.span_suggestion_with_applicability(
                             place.span.between(val.span),
                             "if you meant to write a comparison against a negative value, add a \
                              space in between `<` and `-`",
                             "< -".to_string(),
+                            Applicability::MaybeIncorrect
                         );
                     }
                     _ => {}

Diff for: src/librustc_resolve/macros.rs

@@ -38,6 +38,7 @@ use syntax::symbol::{Symbol, keywords};
 use syntax::tokenstream::{TokenStream, TokenTree, Delimited};
 use syntax::util::lev_distance::find_best_match_for_name;
 use syntax_pos::{Span, DUMMY_SP};
+use errors::Applicability;
 
 use std::cell::Cell;
 use std::mem;
@@ -938,9 +939,19 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
         if let Some(suggestion) = suggestion {
             if suggestion != name {
                 if let MacroKind::Bang = kind {
-                    err.span_suggestion(span, "you could try the macro", suggestion.to_string());
+                    err.span_suggestion_with_applicability(
+                        span,
+                        "you could try the macro",
+                        suggestion.to_string(),
+                        Applicability::MaybeIncorrect
+                    );
                 } else {
-                    err.span_suggestion(span, "try", suggestion.to_string());
+                    err.span_suggestion_with_applicability(
+                        span,
+                        "try",
+                        suggestion.to_string(),
+                        Applicability::MaybeIncorrect
+                    );
                 }
             } else {
                 err.help("have you added the `#[macro_use]` on the module/import?");
@@ -1065,10 +1076,11 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
             if let Some(span) = span {
                 let found_use = if found_use { "" } else { "\n" };
                 self.session.struct_span_err(err.use_span, err.warn_msg)
-                    .span_suggestion(
+                    .span_suggestion_with_applicability(
                         span,
                         "instead, import the procedural macro like any other item",
                         format!("use {}::{};{}", err.crate_name, err.name, found_use),
+                        Applicability::MachineApplicable
                     ).emit();
             } else {
                 self.session.struct_span_err(err.use_span, err.warn_msg)

Diff for: src/librustc_save_analysis/Cargo.toml

@@ -16,7 +16,7 @@ rustc_target = { path = "../librustc_target" }
 rustc_typeck = { path = "../librustc_typeck" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
-rls-data = "0.16"
+rls-data = "0.18"
 rls-span = "0.4"
 # FIXME(#40527) should move rustc serialize out of tree
 rustc-serialize = "0.3"

Diff for: src/librustc_typeck/check/callee.rs

@@ -20,6 +20,7 @@ use rustc::ty::adjustment::{Adjustment, Adjust, AllowTwoPhase, AutoBorrow, AutoB
 use rustc_target::spec::abi;
 use syntax::ast::Ident;
 use syntax_pos::Span;
+use errors::Applicability;
 
 use rustc::hir;
 
@@ -234,10 +235,13 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 err.span_label(call_expr.span, "not a function");
 
                 if let Some(ref path) = unit_variant {
-                    err.span_suggestion(call_expr.span,
-                                        &format!("`{}` is a unit variant, you need to write it \
-                                                  without the parenthesis", path),
-                                        path.to_string());
+                    err.span_suggestion_with_applicability(
+                        call_expr.span,
+                        &format!("`{}` is a unit variant, you need to write it \
+                                 without the parenthesis", path),
+                        path.to_string(),
+                        Applicability::MachineApplicable
+                    );
                 }
 
                 if let hir::ExprKind::Call(ref expr, _) = call_expr.node {