Rollup merge of #93363 - lcnr:pass-by-value, r=petrochenkov

`#[rustc_pass_by_value]` cleanup

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -607,7 +607,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
         &mut self,
         macro_def: &ast::MacroDef,
         ident: &Ident,
-        sp: &Span,
+        sp: Span,
         print_visibility: impl FnOnce(&mut Self),
     ) {
         let (kw, has_bang) = if macro_def.macro_rules {
@@ -623,7 +623,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
             macro_def.body.delim(),
             &macro_def.body.inner_tokens(),
             true,
-            *sp,
+            sp,
         );
         if macro_def.body.need_semicolon() {
             self.word(";");

compiler/rustc_ast_pretty/src/pprust/state/item.rs

@@ -347,7 +347,7 @@ impl<'a> State<'a> {
                 }
             }
             ast::ItemKind::MacroDef(ref macro_def) => {
-                self.print_mac_def(macro_def, &item.ident, &item.span, |state| {
+                self.print_mac_def(macro_def, &item.ident, item.span, |state| {
                     state.print_visibility(&item.vis)
                 });
             }

compiler/rustc_feature/src/builtin_attrs.rs

@@ -625,7 +625,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     ),
     rustc_attr!(
         rustc_pass_by_value, Normal,
-        template!(Word), WarnFollowing,
+        template!(Word), ErrorFollowing,
         "#[rustc_pass_by_value] is used to mark types that must be passed by value instead of reference."
     ),
     BuiltinAttribute {

compiler/rustc_hir_pretty/src/lib.rs

@@ -571,7 +571,7 @@ impl<'a> State<'a> {
                 self.ann.nested(self, Nested::Body(body));
             }
             hir::ItemKind::Macro(ref macro_def) => {
-                self.print_mac_def(macro_def, &item.ident, &item.span, |state| {
+                self.print_mac_def(macro_def, &item.ident, item.span, |state| {
                     state.print_visibility(&item.vis)
                 });
             }

compiler/rustc_lint/src/non_fmt_panic.rs

@@ -336,5 +336,5 @@ fn is_arg_inside_call(arg: Span, call: Span) -> bool {
     // panic call in the source file, to avoid invalid suggestions when macros are involved.
     // We specifically check for the spans to not be identical, as that happens sometimes when
     // proc_macros lie about spans and apply the same span to all the tokens they produce.
-    call.contains(arg) && !call.source_equal(&arg)
+    call.contains(arg) && !call.source_equal(arg)
 }

compiler/rustc_lint/src/pass_by_value.rs

@@ -76,10 +76,10 @@ fn gen_args(cx: &LateContext<'_>, segment: &PathSegment<'_>) -> String {
             .map(|arg| match arg {
                 GenericArg::Lifetime(lt) => lt.name.ident().to_string(),
                 GenericArg::Type(ty) => {
-                    cx.tcx.sess.source_map().span_to_snippet(ty.span).unwrap_or_default()
+                    cx.tcx.sess.source_map().span_to_snippet(ty.span).unwrap_or_else(|_| "_".into())
                 }
                 GenericArg::Const(c) => {
-                    cx.tcx.sess.source_map().span_to_snippet(c.span).unwrap_or_default()
+                    cx.tcx.sess.source_map().span_to_snippet(c.span).unwrap_or_else(|_| "_".into())
                 }
                 GenericArg::Infer(_) => String::from("_"),
             })

compiler/rustc_middle/src/mir/spanview.rs

@@ -230,7 +230,7 @@ where
 }
 
 /// Format a string showing the start line and column, and end line and column within a file.
-pub fn source_range_no_file<'tcx>(tcx: TyCtxt<'tcx>, span: &Span) -> String {
+pub fn source_range_no_file<'tcx>(tcx: TyCtxt<'tcx>, span: Span) -> String {
     let source_map = tcx.sess.source_map();
     let start = source_map.lookup_char_pos(span.lo());
     let end = source_map.lookup_char_pos(span.hi());
@@ -629,7 +629,7 @@ fn tooltip<'tcx>(
     let mut text = Vec::new();
     text.push(format!("{}: {}:", spanview_id, &source_map.span_to_embeddable_string(span)));
     for statement in statements {
-        let source_range = source_range_no_file(tcx, &statement.source_info.span);
+        let source_range = source_range_no_file(tcx, statement.source_info.span);
         text.push(format!(
             "\n{}{}: {}: {:?}",
             TOOLTIP_INDENT,
@@ -639,7 +639,7 @@ fn tooltip<'tcx>(
         ));
     }
     if let Some(term) = terminator {
-        let source_range = source_range_no_file(tcx, &term.source_info.span);
+        let source_range = source_range_no_file(tcx, term.source_info.span);
         text.push(format!(
             "\n{}{}: {}: {:?}",
             TOOLTIP_INDENT,

compiler/rustc_mir_transform/src/coverage/spans.rs

@@ -28,7 +28,7 @@ impl CoverageStatement {
                 let stmt = &mir_body[bb].statements[stmt_index];
                 format!(
                     "{}: @{}[{}]: {:?}",
-                    source_range_no_file(tcx, &span),
+                    source_range_no_file(tcx, span),
                     bb.index(),
                     stmt_index,
                     stmt
@@ -38,7 +38,7 @@ impl CoverageStatement {
                 let term = mir_body[bb].terminator();
                 format!(
                     "{}: @{}.{}: {:?}",
-                    source_range_no_file(tcx, &span),
+                    source_range_no_file(tcx, span),
                     bb.index(),
                     term_type(&term.kind),
                     term.kind
@@ -155,7 +155,7 @@ impl CoverageSpan {
     pub fn format<'tcx>(&self, tcx: TyCtxt<'tcx>, mir_body: &mir::Body<'tcx>) -> String {
         format!(
             "{}\n    {}",
-            source_range_no_file(tcx, &self.span),
+            source_range_no_file(tcx, self.span),
             self.format_coverage_statements(tcx, mir_body).replace('\n', "\n    "),
         )
     }

compiler/rustc_span/src/lib.rs

@@ -612,7 +612,7 @@ impl Span {
 
     #[inline]
     /// Returns `true` if `hi == lo`.
-    pub fn is_empty(&self) -> bool {
+    pub fn is_empty(self) -> bool {
         let span = self.data_untracked();
         span.hi == span.lo
     }
@@ -640,7 +640,7 @@ impl Span {
     ///
     /// Use this instead of `==` when either span could be generated code,
     /// and you only care that they point to the same bytes of source text.
-    pub fn source_equal(&self, other: &Span) -> bool {
+    pub fn source_equal(self, other: Span) -> bool {
         let span = self.data();
         let other = other.data();
         span.lo == other.lo && span.hi == other.hi
@@ -681,17 +681,17 @@ impl Span {
     }
 
     #[inline]
-    pub fn rust_2015(&self) -> bool {
+    pub fn rust_2015(self) -> bool {
         self.edition() == edition::Edition::Edition2015
     }
 
     #[inline]
-    pub fn rust_2018(&self) -> bool {
+    pub fn rust_2018(self) -> bool {
         self.edition() >= edition::Edition::Edition2018
     }
 
     #[inline]
-    pub fn rust_2021(&self) -> bool {
+    pub fn rust_2021(self) -> bool {
         self.edition() >= edition::Edition::Edition2021
     }
 
@@ -712,15 +712,15 @@ impl Span {
     /// Checks if a span is "internal" to a macro in which `#[unstable]`
     /// items can be used (that is, a macro marked with
     /// `#[allow_internal_unstable]`).
-    pub fn allows_unstable(&self, feature: Symbol) -> bool {
+    pub fn allows_unstable(self, feature: Symbol) -> bool {
         self.ctxt()
             .outer_expn_data()
             .allow_internal_unstable
             .map_or(false, |features| features.iter().any(|&f| f == feature))
     }
 
     /// Checks if this span arises from a compiler desugaring of kind `kind`.
-    pub fn is_desugaring(&self, kind: DesugaringKind) -> bool {
+    pub fn is_desugaring(self, kind: DesugaringKind) -> bool {
         match self.ctxt().outer_expn_data().kind {
             ExpnKind::Desugaring(k) => k == kind,
             _ => false,
@@ -729,7 +729,7 @@ impl Span {
 
     /// Returns the compiler desugaring that created this span, or `None`
     /// if this span is not from a desugaring.
-    pub fn desugaring_kind(&self) -> Option<DesugaringKind> {
+    pub fn desugaring_kind(self) -> Option<DesugaringKind> {
         match self.ctxt().outer_expn_data().kind {
             ExpnKind::Desugaring(k) => Some(k),
             _ => None,
@@ -739,7 +739,7 @@ impl Span {
     /// Checks if a span is "internal" to a macro in which `unsafe`
     /// can be used without triggering the `unsafe_code` lint.
     //  (that is, a macro marked with `#[allow_internal_unsafe]`).
-    pub fn allows_unsafe(&self) -> bool {
+    pub fn allows_unsafe(self) -> bool {
         self.ctxt().outer_expn_data().allow_internal_unsafe
     }
 
@@ -752,7 +752,7 @@ impl Span {
                     return None;
                 }
 
-                let is_recursive = expn_data.call_site.source_equal(&prev_span);
+                let is_recursive = expn_data.call_site.source_equal(prev_span);
 
                 prev_span = self;
                 self = expn_data.call_site;
@@ -866,13 +866,13 @@ impl Span {
 
     /// Equivalent of `Span::call_site` from the proc macro API,
     /// except that the location is taken from the `self` span.
-    pub fn with_call_site_ctxt(&self, expn_id: ExpnId) -> Span {
+    pub fn with_call_site_ctxt(self, expn_id: ExpnId) -> Span {
         self.with_ctxt_from_mark(expn_id, Transparency::Transparent)
     }
 
     /// Equivalent of `Span::mixed_site` from the proc macro API,
     /// except that the location is taken from the `self` span.
-    pub fn with_mixed_site_ctxt(&self, expn_id: ExpnId) -> Span {
+    pub fn with_mixed_site_ctxt(self, expn_id: ExpnId) -> Span {
         self.with_ctxt_from_mark(expn_id, Transparency::SemiTransparent)
     }
 

compiler/rustc_span/src/span_encoding.rs

@@ -61,6 +61,15 @@ use rustc_data_structures::fx::FxIndexSet;
 /// using the callback `SPAN_TRACK` to access the query engine.
 ///
 #[derive(Clone, Copy, Eq, PartialEq, Hash)]
+// FIXME(@lcnr): Enable this attribute once the bootstrap
+// compiler knows of `rustc_pass_by_value`.
+//
+// Right now, this lint would only trigger when compiling the
+// stage 2 compiler, which is fairly annoying as there are
+// a lot of places using `&Span` right now. After the next bootstrap bump,
+// the lint will already trigger when using stage 1, which is a lot less annoying.
+//
+// #[cfg_attr(not(bootstrap), rustc_pass_by_value)]
 pub struct Span {
     base_or_index: u32,
     len_or_tag: u16,