Rollup merge of #53504 - ekse:suggestions-applicability-2, r=estebank

Set applicability for more suggestions.

Converts a couple more calls to `span_suggestion_with_applicability`  (#50723). To be on the safe side, I marked suggestions that depend on the intent of the user or that are potentially lossy conversions as MaybeIncorrect.

r? @estebank

Author: GuillaumeGomez

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
+                    );
                 }
             }
             _ => {

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
                         );
                     }
                     _ => {}

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)

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 {