Revert "Rollup merge of #72389 - Aaron1011:feature/move-fn-self-msg, …

…r=nikomatsakis" This reverts commit 372cb9b, reversing changes made to 5c61a8d.
rust-lang · Manishearth · Jun 18, 2020 · Jun 20, 2020 · Apr 29, 2020 · Jun 20, 2020
commit 20866c5cf74f0524f82f053c963bd008ff3898a9
diff --git a/src/librustc_ast_lowering/expr.rs b/src/librustc_ast_lowering/expr.rs
@@ -9,7 +9,7 @@ use rustc_data_structures::thin_vec::ThinVec;
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::def::Res;
-use rustc_span::source_map::{respan, DesugaringKind, ForLoopLoc, Span, Spanned};
+use rustc_span::source_map::{respan, DesugaringKind, Span, Spanned};
 use rustc_span::symbol::{sym, Ident, Symbol};
 use rustc_target::asm;
 use std::collections::hash_map::Entry;
@@ -25,7 +25,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     pub(super) fn lower_expr_mut(&mut self, e: &Expr) -> hir::Expr<'hir> {
-        let mut span = e.span;
         ensure_sufficient_stack(|| {
             let kind = match e.kind {
                 ExprKind::Box(ref inner) => hir::ExprKind::Box(self.lower_expr(inner)),
@@ -54,7 +53,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     hir::ExprKind::MethodCall(hir_seg, seg.ident.span, args, span)
                 }
                 ExprKind::Binary(binop, ref lhs, ref rhs) => {
-                    span = self.mark_span_with_reason(DesugaringKind::Operator, e.span, None);
                     let binop = self.lower_binop(binop);
                     let lhs = self.lower_expr(lhs);
                     let rhs = self.lower_expr(rhs);
@@ -224,7 +222,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             hir::Expr {
                 hir_id: self.lower_node_id(e.id),
                 kind,
-                span,
+                span: e.span,
                 attrs: e.attrs.iter().map(|a| self.lower_attr(a)).collect::<Vec<_>>().into(),
             }
         })
@@ -239,7 +237,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     fn lower_binop(&mut self, b: BinOp) -> hir::BinOp {
-        let span = self.mark_span_with_reason(DesugaringKind::Operator, b.span, None);
         Spanned {
             node: match b.node {
                 BinOpKind::Add => hir::BinOpKind::Add,
@@ -261,7 +258,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 BinOpKind::Ge => hir::BinOpKind::Ge,
                 BinOpKind::Gt => hir::BinOpKind::Gt,
             },
-            span,
+            span: b.span,
         }
     }
 
@@ -1363,14 +1360,9 @@ impl<'hir> LoweringContext<'_, 'hir> {
         body: &Block,
         opt_label: Option<Label>,
     ) -> hir::Expr<'hir> {
-        let orig_head_span = head.span;
         // expand <head>
         let mut head = self.lower_expr_mut(head);
-        let desugared_span = self.mark_span_with_reason(
-            DesugaringKind::ForLoop(ForLoopLoc::Head),
-            orig_head_span,
-            None,
-        );
+        let desugared_span = self.mark_span_with_reason(DesugaringKind::ForLoop, head.span, None);
         head.span = desugared_span;
 
         let iter = Ident::with_dummy_span(sym::iter);
@@ -1465,16 +1457,10 @@ impl<'hir> LoweringContext<'_, 'hir> {
         // `mut iter => { ... }`
         let iter_arm = self.arm(iter_pat, loop_expr);
 
-        let into_iter_span = self.mark_span_with_reason(
-            DesugaringKind::ForLoop(ForLoopLoc::IntoIter),
-            orig_head_span,
-            None,
-        );
-
         // `match ::std::iter::IntoIterator::into_iter(<head>) { ... }`
         let into_iter_expr = {
             let into_iter_path = &[sym::iter, sym::IntoIterator, sym::into_iter];
-            self.expr_call_std_path(into_iter_span, into_iter_path, arena_vec![self; head])
+            self.expr_call_std_path(desugared_span, into_iter_path, arena_vec![self; head])
         };
 
         let match_expr = self.arena.alloc(self.expr_match(

diff --git a/src/librustc_infer/infer/error_reporting/need_type_info.rs b/src/librustc_infer/infer/error_reporting/need_type_info.rs
@@ -468,7 +468,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             let msg = if let Some(simple_ident) = pattern.simple_ident() {
                 match pattern.span.desugaring_kind() {
                     None => format!("consider giving `{}` {}", simple_ident, suffix),
-                    Some(DesugaringKind::ForLoop(_)) => {
+                    Some(DesugaringKind::ForLoop) => {
                         "the element type for this iterator is not specified".to_string()
                     }
                     _ => format!("this needs {}", suffix),

diff --git a/src/librustc_metadata/rmeta/decoder.rs b/src/librustc_metadata/rmeta/decoder.rs
@@ -1318,13 +1318,13 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
         }
     }
 
-    fn get_fn_param_names(&self, tcx: TyCtxt<'tcx>, id: DefIndex) -> &'tcx [Ident] {
+    fn get_fn_param_names(&self, tcx: TyCtxt<'tcx>, id: DefIndex) -> &'tcx [Symbol] {
         let param_names = match self.kind(id) {
             EntryKind::Fn(data) | EntryKind::ForeignFn(data) => data.decode(self).param_names,
             EntryKind::AssocFn(data) => data.decode(self).fn_data.param_names,
             _ => Lazy::empty(),
         };
-        tcx.arena.alloc_from_iter(param_names.decode((self, tcx)))
+        tcx.arena.alloc_from_iter(param_names.decode(self))
     }
 
     fn exported_symbols(

diff --git a/src/librustc_metadata/rmeta/encoder.rs b/src/librustc_metadata/rmeta/encoder.rs
@@ -30,7 +30,7 @@ use rustc_middle::ty::{self, SymbolName, Ty, TyCtxt};
 use rustc_serialize::{opaque, Encodable, Encoder, SpecializedEncoder, UseSpecializedEncodable};
 use rustc_session::config::CrateType;
 use rustc_span::source_map::Spanned;
-use rustc_span::symbol::{sym, Ident, Symbol};
+use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{self, ExternalSource, FileName, SourceFile, Span};
 use rustc_target::abi::VariantIdx;
 use std::hash::Hash;
@@ -1009,12 +1009,18 @@ impl EncodeContext<'tcx> {
         }
     }
 
-    fn encode_fn_param_names_for_body(&mut self, body_id: hir::BodyId) -> Lazy<[Ident]> {
-        self.tcx.dep_graph.with_ignore(|| self.lazy(self.tcx.hir().body_param_names(body_id)))
+    fn encode_fn_param_names_for_body(&mut self, body_id: hir::BodyId) -> Lazy<[Symbol]> {
+        self.tcx.dep_graph.with_ignore(|| {
+            let body = self.tcx.hir().body(body_id);
+            self.lazy(body.params.iter().map(|arg| match arg.pat.kind {
+                hir::PatKind::Binding(_, _, ident, _) => ident.name,
+                _ => kw::Invalid,
+            }))
+        })
     }
 
-    fn encode_fn_param_names(&mut self, param_names: &[Ident]) -> Lazy<[Ident]> {
-        self.lazy(param_names.iter())
+    fn encode_fn_param_names(&mut self, param_names: &[Ident]) -> Lazy<[Symbol]> {
+        self.lazy(param_names.iter().map(|ident| ident.name))
     }
 
     fn encode_optimized_mir(&mut self, def_id: LocalDefId) {

diff --git a/src/librustc_metadata/rmeta/mod.rs b/src/librustc_metadata/rmeta/mod.rs
@@ -19,7 +19,7 @@ use rustc_serialize::opaque::Encoder;
 use rustc_session::config::SymbolManglingVersion;
 use rustc_session::CrateDisambiguator;
 use rustc_span::edition::Edition;
-use rustc_span::symbol::{Ident, Symbol};
+use rustc_span::symbol::Symbol;
 use rustc_span::{self, Span};
 use rustc_target::spec::{PanicStrategy, TargetTriple};
 
@@ -327,7 +327,7 @@ struct ModData {
 struct FnData {
     asyncness: hir::IsAsync,
     constness: hir::Constness,
-    param_names: Lazy<[Ident]>,
+    param_names: Lazy<[Symbol]>,
 }
 
 #[derive(RustcEncodable, RustcDecodable)]

diff --git a/src/librustc_middle/hir/map/mod.rs b/src/librustc_middle/hir/map/mod.rs
@@ -14,7 +14,7 @@ use rustc_hir::*;
 use rustc_index::vec::IndexVec;
 use rustc_span::hygiene::MacroKind;
 use rustc_span::source_map::Spanned;
-use rustc_span::symbol::{kw, Ident, Symbol};
+use rustc_span::symbol::{kw, Symbol};
 use rustc_span::Span;
 use rustc_target::spec::abi::Abi;
 
@@ -374,13 +374,6 @@ impl<'hir> Map<'hir> {
         })
     }
 
-    pub fn body_param_names(&self, id: BodyId) -> impl Iterator<Item = Ident> + 'hir {
-        self.body(id).params.iter().map(|arg| match arg.pat.kind {
-            PatKind::Binding(_, _, ident, _) => ident,
-            _ => Ident::new(kw::Invalid, rustc_span::DUMMY_SP),
-        })
-    }
-
     /// Returns the `BodyOwnerKind` of this `LocalDefId`.
     ///
     /// Panics if `LocalDefId` does not have an associated body.

diff --git a/src/librustc_middle/hir/mod.rs b/src/librustc_middle/hir/mod.rs
@@ -12,7 +12,10 @@ use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_hir::def_id::{LocalDefId, LOCAL_CRATE};
-use rustc_hir::*;
+use rustc_hir::Body;
+use rustc_hir::HirId;
+use rustc_hir::ItemLocalId;
+use rustc_hir::Node;
 use rustc_index::vec::IndexVec;
 
 pub struct Owner<'tcx> {
@@ -76,20 +79,5 @@ pub fn provide(providers: &mut Providers<'_>) {
     };
     providers.hir_owner = |tcx, id| tcx.index_hir(LOCAL_CRATE).map[id].signature;
     providers.hir_owner_nodes = |tcx, id| tcx.index_hir(LOCAL_CRATE).map[id].with_bodies.as_deref();
-    providers.fn_arg_names = |tcx, id| {
-        let hir = tcx.hir();
-        let hir_id = hir.as_local_hir_id(id.expect_local());
-        if let Some(body_id) = hir.maybe_body_owned_by(hir_id) {
-            tcx.arena.alloc_from_iter(hir.body_param_names(body_id))
-        } else if let Node::TraitItem(&TraitItem {
-            kind: TraitItemKind::Fn(_, TraitFn::Required(idents)),
-            ..
-        }) = hir.get(hir_id)
-        {
-            tcx.arena.alloc_slice(idents)
-        } else {
-            span_bug!(hir.span(hir_id), "fn_arg_names: unexpected item {:?}", id);
-        }
-    };
     map::provide(providers);
 }
diff --git a/src/librustc_middle/lint.rs b/src/librustc_middle/lint.rs
@@ -339,9 +339,7 @@ pub fn struct_lint_level<'s, 'd>(
 pub fn in_external_macro(sess: &Session, span: Span) -> bool {
     let expn_data = span.ctxt().outer_expn_data();
     match expn_data.kind {
-        ExpnKind::Root
-        | ExpnKind::Desugaring(DesugaringKind::ForLoop(_))
-        | ExpnKind::Desugaring(DesugaringKind::Operator) => false,
+        ExpnKind::Root | ExpnKind::Desugaring(DesugaringKind::ForLoop) => false,
         ExpnKind::AstPass(_) | ExpnKind::Desugaring(_) => true, // well, it's "external"
         ExpnKind::Macro(MacroKind::Bang, _) => {
             // Dummy span for the `def_site` means it's an external macro.

diff --git a/src/librustc_middle/query/mod.rs b/src/librustc_middle/query/mod.rs
@@ -723,7 +723,7 @@ rustc_queries! {
     }
 
     Other {
-        query fn_arg_names(def_id: DefId) -> &'tcx [rustc_span::symbol::Ident] {
+        query fn_arg_names(def_id: DefId) -> &'tcx [Symbol] {
             desc { |tcx| "looking up function parameter names for `{}`", tcx.def_path_str(def_id) }
         }
         /// Gets the rendered value of the specified constant or associated constant.

diff --git a/src/librustc_mir/borrow_check/diagnostics/conflict_errors.rs b/src/librustc_mir/borrow_check/diagnostics/conflict_errors.rs
@@ -24,8 +24,7 @@ use crate::borrow_check::{
 };
 
 use super::{
-    explain_borrow::BorrowExplanation, FnSelfUseKind, IncludingDowncast, RegionName,
-    RegionNameSource, UseSpans,
+    explain_borrow::BorrowExplanation, IncludingDowncast, RegionName, RegionNameSource, UseSpans,
 };
 
 #[derive(Debug)]
@@ -151,70 +150,13 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         format!("value moved{} here, in previous iteration of loop", move_msg),
                     );
                 } else {
-                    if let UseSpans::FnSelfUse { var_span, fn_call_span, fn_span, kind } =
-                        move_spans
-                    {
-                        let place_name = self
-                            .describe_place(moved_place.as_ref())
-                            .map(|n| format!("`{}`", n))
-                            .unwrap_or_else(|| "value".to_owned());
-                        match kind {
-                            FnSelfUseKind::FnOnceCall => {
-                                err.span_label(
-                                    fn_call_span,
-                                    &format!("{} moved due to this call", place_name),
-                                );
-                                err.span_note(
-                                    var_span,
-                                    "this value implements `FnOnce`, which causes it to be moved when called",
-                                );
-                            }
-                            FnSelfUseKind::Operator { self_arg } => {
-                                err.span_label(
-                                    fn_call_span,
-                                    &format!("{} moved due to usage in operator", place_name),
-                                );
-                                if self.fn_self_span_reported.insert(fn_span) {
-                                    err.span_note(
-                                        self_arg.span,
-                                        "calling this operator moves the left-hand side",
-                                    );
-                                }
-                            }
-                            FnSelfUseKind::Normal { self_arg, implicit_into_iter } => {
-                                if implicit_into_iter {
-                                    err.span_label(
-                                        fn_call_span,
-                                        &format!(
-                                            "{} moved due to this implicit call to `.into_iter()`",
-                                            place_name
-                                        ),
-                                    );
-                                } else {
-                                    err.span_label(
-                                        fn_call_span,
-                                        &format!("{} moved due to this method call", place_name),
-                                    );
-                                }
-                                // Avoid pointing to the same function in multiple different
-                                // error messages
-                                if self.fn_self_span_reported.insert(self_arg.span) {
-                                    err.span_note(
-                                        self_arg.span,
-                                        &format!("this function consumes the receiver `self` by taking ownership of it, which moves {}", place_name)
-                                    );
-                                }
-                            }
-                        }
-                    } else {
-                        err.span_label(move_span, format!("value moved{} here", move_msg));
-                        move_spans.var_span_label(
-                            &mut err,
-                            format!("variable moved due to use{}", move_spans.describe()),
-                        );
-                    }
+                    err.span_label(move_span, format!("value moved{} here", move_msg));
+                    move_spans.var_span_label(
+                        &mut err,
+                        format!("variable moved due to use{}", move_spans.describe()),
+                    );
                 }
-                if let Some(DesugaringKind::ForLoop(_)) = move_span.desugaring_kind() {
+                if Some(DesugaringKind::ForLoop) == move_span.desugaring_kind() {
                     let sess = self.infcx.tcx.sess;
                     if let Ok(snippet) = sess.source_map().span_to_snippet(move_span) {
                         err.span_suggestion(

diff --git a/src/librustc_mir/borrow_check/diagnostics/explain_borrow.rs b/src/librustc_mir/borrow_check/diagnostics/explain_borrow.rs
@@ -509,7 +509,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 // Used in a closure.
                 (LaterUseKind::ClosureCapture, var_span)
             }
-            UseSpans::OtherUse(span) | UseSpans::FnSelfUse { var_span: span, .. } => {
+            UseSpans::OtherUse(span) => {
                 let block = &self.body.basic_blocks()[location.block];
 
                 let kind = if let Some(&Statement {