Auto merge of #51880 - varkor:generics-hir-generalisation-followup, r…

…=eddyb The Great Generics Generalisation: HIR Followup Addresses the final comments in #48149. r? @eddyb, but there are a few things I have yet to clean up. Making the PR now to more easily see when things break. cc @yodaldevoid
rust-lang · Aug 20, 2018 · 1558ae7 · 1558ae7
2 parents bf1e461 + ee9bd0f
commit 1558ae7
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diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs
@@ -401,6 +401,13 @@ impl GenericArg {
             GenericArg::Type(t) => t.span,
         }
     }
+
+    pub fn id(&self) -> NodeId {
+        match self {
+            GenericArg::Lifetime(l) => l.id,
+            GenericArg::Type(t) => t.id,
+        }
+    }
 }
 
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
@@ -445,6 +452,22 @@ impl GenericArgs {
         }
         bug!("GenericArgs::inputs: not a `Fn(T) -> U`");
     }
+
+    pub fn own_counts(&self) -> GenericParamCount {
+        // We could cache this as a property of `GenericParamCount`, but
+        // the aim is to refactor this away entirely eventually and the
+        // presence of this method will be a constant reminder.
+        let mut own_counts: GenericParamCount = Default::default();
+
+        for arg in &self.args {
+            match arg {
+                GenericArg::Lifetime(_) => own_counts.lifetimes += 1,
+                GenericArg::Type(_) => own_counts.types += 1,
+            };
+        }
+
+        own_counts
+    }
 }
 
 /// A modifier on a bound, currently this is only used for `?Sized`, where the
@@ -503,6 +526,7 @@ pub struct GenericParam {
     pub kind: GenericParamKind,
 }
 
+#[derive(Default)]
 pub struct GenericParamCount {
     pub lifetimes: usize,
     pub types: usize,
@@ -533,10 +557,7 @@ impl Generics {
         // We could cache this as a property of `GenericParamCount`, but
         // the aim is to refactor this away entirely eventually and the
         // presence of this method will be a constant reminder.
-        let mut own_counts = GenericParamCount {
-            lifetimes: 0,
-            types: 0,
-        };
+        let mut own_counts: GenericParamCount = Default::default();
 
         for param in &self.params {
             match param.kind {

diff --git a/src/librustc/middle/reachable.rs b/src/librustc/middle/reachable.rs
@@ -20,7 +20,7 @@ use hir::map as hir_map;
 use hir::def::Def;
 use hir::def_id::{DefId, CrateNum};
 use rustc_data_structures::sync::Lrc;
-use ty::{self, TyCtxt, GenericParamDefKind};
+use ty::{self, TyCtxt};
 use ty::query::Providers;
 use middle::privacy;
 use session::config;
@@ -34,18 +34,6 @@ use hir::intravisit::{Visitor, NestedVisitorMap};
 use hir::itemlikevisit::ItemLikeVisitor;
 use hir::intravisit;
 
-// Returns true if the given set of generics implies that the item it's
-// associated with must be inlined.
-fn generics_require_inlining(generics: &ty::Generics) -> bool {
-    for param in &generics.params {
-        match param.kind {
-            GenericParamDefKind::Lifetime { .. } => {}
-            GenericParamDefKind::Type { .. } => return true,
-        }
-    }
-    false
-}
-
 // Returns true if the given item must be inlined because it may be
 // monomorphized or it was marked with `#[inline]`. This will only return
 // true for functions.
@@ -60,7 +48,7 @@ fn item_might_be_inlined(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         hir::ItemKind::Impl(..) |
         hir::ItemKind::Fn(..) => {
             let generics = tcx.generics_of(tcx.hir.local_def_id(item.id));
-            generics_require_inlining(generics)
+            generics.requires_monomorphization(tcx)
         }
         _ => false,
     }
@@ -71,7 +59,7 @@ fn method_might_be_inlined<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                      impl_src: DefId) -> bool {
     let codegen_fn_attrs = tcx.codegen_fn_attrs(impl_item.hir_id.owner_def_id());
     let generics = tcx.generics_of(tcx.hir.local_def_id(impl_item.id));
-    if codegen_fn_attrs.requests_inline() || generics_require_inlining(generics) {
+    if codegen_fn_attrs.requests_inline() || generics.requires_monomorphization(tcx) {
         return true
     }
     if let Some(impl_node_id) = tcx.hir.as_local_node_id(impl_src) {
@@ -189,8 +177,7 @@ impl<'a, 'tcx> ReachableContext<'a, 'tcx> {
                     hir::ImplItemKind::Method(..) => {
                         let attrs = self.tcx.codegen_fn_attrs(def_id);
                         let generics = self.tcx.generics_of(def_id);
-                        if generics_require_inlining(&generics) ||
-                                attrs.requests_inline() {
+                        if generics.requires_monomorphization(self.tcx) || attrs.requests_inline() {
                             true
                         } else {
                             let impl_did = self.tcx
@@ -203,7 +190,7 @@ impl<'a, 'tcx> ReachableContext<'a, 'tcx> {
                             match self.tcx.hir.expect_item(impl_node_id).node {
                                 hir::ItemKind::Impl(..) => {
                                     let generics = self.tcx.generics_of(impl_did);
-                                    generics_require_inlining(&generics)
+                                    generics.requires_monomorphization(self.tcx)
                                 }
                                 _ => false
                             }

diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
@@ -881,6 +881,7 @@ impl GenericParamDef {
     }
 }
 
+#[derive(Default)]
 pub struct GenericParamCount {
     pub lifetimes: usize,
     pub types: usize,
@@ -913,15 +914,12 @@ impl<'a, 'gcx, 'tcx> Generics {
         // We could cache this as a property of `GenericParamCount`, but
         // the aim is to refactor this away entirely eventually and the
         // presence of this method will be a constant reminder.
-        let mut own_counts = GenericParamCount {
-            lifetimes: 0,
-            types: 0,
-        };
+        let mut own_counts: GenericParamCount = Default::default();
 
         for param in &self.params {
             match param.kind {
                 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
-                GenericParamDefKind::Type {..} => own_counts.types += 1,
+                GenericParamDefKind::Type { .. } => own_counts.types += 1,
             };
         }
 
@@ -931,7 +929,7 @@ impl<'a, 'gcx, 'tcx> Generics {
     pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
         for param in &self.params {
             match param.kind {
-                GenericParamDefKind::Type {..} => return true,
+                GenericParamDefKind::Type { .. } => return true,
                 GenericParamDefKind::Lifetime => {}
             }
         }

diff --git a/src/librustc/ty/subst.rs b/src/librustc/ty/subst.rs
@@ -231,7 +231,6 @@ impl<'a, 'gcx, 'tcx> Substs<'tcx> {
                     mk_kind: &mut F)
     where F: FnMut(&ty::GenericParamDef, &[Kind<'tcx>]) -> Kind<'tcx>
     {
-
         if let Some(def_id) = defs.parent {
             let parent_defs = tcx.generics_of(def_id);
             Substs::fill_item(substs, tcx, parent_defs, mk_kind);

diff --git a/src/librustc/util/ppaux.rs b/src/librustc/util/ppaux.rs
@@ -262,10 +262,7 @@ impl PrintContext {
         let verbose = self.is_verbose;
         let mut num_supplied_defaults = 0;
         let mut has_self = false;
-        let mut own_counts = GenericParamCount {
-            lifetimes: 0,
-            types: 0,
-        };
+        let mut own_counts: GenericParamCount = Default::default();
         let mut is_value_path = false;
         let fn_trait_kind = ty::tls::with(|tcx| {
             // Unfortunately, some kinds of items (e.g., closures) don't have

diff --git a/src/librustc_lint/types.rs b/src/librustc_lint/types.rs
@@ -819,14 +819,6 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for VariantSizeDifferences {
     fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
         if let hir::ItemKind::Enum(ref enum_definition, _) = it.node {
             let item_def_id = cx.tcx.hir.local_def_id(it.id);
-            let generics = cx.tcx.generics_of(item_def_id);
-            for param in &generics.params {
-                match param.kind {
-                    ty::GenericParamDefKind::Lifetime { .. } => {},
-                    ty::GenericParamDefKind::Type { .. } => return,
-                }
-            }
-            // Sizes only make sense for non-generic types.
             let t = cx.tcx.type_of(item_def_id);
             let ty = cx.tcx.erase_regions(&t);
             match cx.layout_of(ty) {

diff --git a/src/librustc_metadata/encoder.rs b/src/librustc_metadata/encoder.rs
@@ -1262,12 +1262,9 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
                 hir::ItemKind::Const(..) => self.encode_optimized_mir(def_id),
                 hir::ItemKind::Fn(_, header, ..) => {
                     let generics = tcx.generics_of(def_id);
-                    let has_types = generics.params.iter().any(|param| match param.kind {
-                        ty::GenericParamDefKind::Type { .. } => true,
-                        _ => false,
-                    });
                     let needs_inline =
-                        (has_types || tcx.codegen_fn_attrs(def_id).requests_inline()) &&
+                        (generics.requires_monomorphization(tcx) ||
+                         tcx.codegen_fn_attrs(def_id).requests_inline()) &&
                             !self.metadata_output_only();
                     let always_encode_mir = self.tcx.sess.opts.debugging_opts.always_encode_mir;
                     if needs_inline
@@ -1683,15 +1680,17 @@ impl<'a, 'b, 'tcx> IndexBuilder<'a, 'b, 'tcx> {
     }
 
     fn encode_info_for_generics(&mut self, generics: &hir::Generics) {
-        generics.params.iter().for_each(|param| match param.kind {
-            hir::GenericParamKind::Lifetime { .. } => {}
-            hir::GenericParamKind::Type { ref default, .. } => {
-                let def_id = self.tcx.hir.local_def_id(param.id);
-                let has_default = Untracked(default.is_some());
-                let encode_info = IsolatedEncoder::encode_info_for_ty_param;
-                self.record(def_id, encode_info, (def_id, has_default));
+        for param in &generics.params {
+            match param.kind {
+                hir::GenericParamKind::Lifetime { .. } => {}
+                hir::GenericParamKind::Type { ref default, .. } => {
+                    let def_id = self.tcx.hir.local_def_id(param.id);
+                    let has_default = Untracked(default.is_some());
+                    let encode_info = IsolatedEncoder::encode_info_for_ty_param;
+                    self.record(def_id, encode_info, (def_id, has_default));
+                }
             }
-        });
+        }
     }
 
     fn encode_info_for_ty(&mut self, ty: &hir::Ty) {

diff --git a/src/librustc_passes/ast_validation.rs b/src/librustc_passes/ast_validation.rs
@@ -539,10 +539,9 @@ impl<'a> Visitor<'a> for NestedImplTraitVisitor<'a> {
     fn visit_generic_args(&mut self, _: Span, generic_args: &'a GenericArgs) {
         match *generic_args {
             GenericArgs::AngleBracketed(ref data) => {
-                data.args.iter().for_each(|arg| match arg {
-                    GenericArg::Type(ty) => self.visit_ty(ty),
-                    _ => {}
-                });
+                for arg in &data.args {
+                    self.visit_generic_arg(arg)
+                }
                 for type_binding in &data.bindings {
                     // Type bindings such as `Item=impl Debug` in `Iterator<Item=Debug>`
                     // are allowed to contain nested `impl Trait`.

diff --git a/src/librustc_privacy/lib.rs b/src/librustc_privacy/lib.rs
@@ -23,7 +23,7 @@ extern crate rustc_typeck;
 extern crate syntax_pos;
 extern crate rustc_data_structures;
 
-use rustc::hir::{self, GenericParamKind, PatKind};
+use rustc::hir::{self, PatKind};
 use rustc::hir::def::Def;
 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, CrateNum, DefId};
 use rustc::hir::intravisit::{self, Visitor, NestedVisitorMap};
@@ -1270,14 +1270,11 @@ impl<'a, 'tcx> Visitor<'tcx> for ObsoleteVisiblePrivateTypesVisitor<'a, 'tcx> {
     }
 
     fn visit_generics(&mut self, generics: &'tcx hir::Generics) {
-        generics.params.iter().for_each(|param| match param.kind {
-            GenericParamKind::Lifetime { .. } => {}
-            GenericParamKind::Type { .. } => {
-                for bound in &param.bounds {
-                    self.check_generic_bound(bound);
-                }
+        for param in &generics.params {
+            for bound in &param.bounds {
+                self.check_generic_bound(bound);
             }
-        });
+        }
         for predicate in &generics.where_clause.predicates {
             match predicate {
                 &hir::WherePredicate::BoundPredicate(ref bound_pred) => {

diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
@@ -822,11 +822,12 @@ impl<'a, 'tcx, 'cl> Visitor<'tcx> for Resolver<'a, 'cl> {
             .filter_map(|param| match param.kind {
                 GenericParamKind::Lifetime { .. } => None,
                 GenericParamKind::Type { ref default, .. } => {
-                    if found_default || default.is_some() {
-                        found_default = true;
-                        return Some((Ident::with_empty_ctxt(param.ident.name), Def::Err));
+                    found_default |= default.is_some();
+                    if found_default {
+                        Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
+                    } else {
+                        None
                     }
-                    None
                 }
             }));
 
@@ -2339,28 +2340,30 @@ impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
             HasTypeParameters(generics, rib_kind) => {
                 let mut function_type_rib = Rib::new(rib_kind);
                 let mut seen_bindings = FxHashMap();
-                generics.params.iter().for_each(|param| match param.kind {
-                    GenericParamKind::Lifetime { .. } => {}
-                    GenericParamKind::Type { .. } => {
-                        let ident = param.ident.modern();
-                        debug!("with_type_parameter_rib: {}", param.id);
-
-                        if seen_bindings.contains_key(&ident) {
-                            let span = seen_bindings.get(&ident).unwrap();
-                            let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
-                                ident.name,
-                                span,
-                            );
-                            resolve_error(self, param.ident.span, err);
-                        }
-                        seen_bindings.entry(ident).or_insert(param.ident.span);
+                for param in &generics.params {
+                    match param.kind {
+                        GenericParamKind::Lifetime { .. } => {}
+                        GenericParamKind::Type { .. } => {
+                            let ident = param.ident.modern();
+                            debug!("with_type_parameter_rib: {}", param.id);
+
+                            if seen_bindings.contains_key(&ident) {
+                                let span = seen_bindings.get(&ident).unwrap();
+                                let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
+                                    ident.name,
+                                    span,
+                                );
+                                resolve_error(self, param.ident.span, err);
+                            }
+                            seen_bindings.entry(ident).or_insert(param.ident.span);
 
-                    // Plain insert (no renaming).
-                    let def = Def::TyParam(self.definitions.local_def_id(param.id));
-                        function_type_rib.bindings.insert(ident, def);
-                        self.record_def(param.id, PathResolution::new(def));
+                        // Plain insert (no renaming).
+                        let def = Def::TyParam(self.definitions.local_def_id(param.id));
+                            function_type_rib.bindings.insert(ident, def);
+                            self.record_def(param.id, PathResolution::new(def));
+                        }
                     }
-                });
+                }
                 self.ribs[TypeNS].push(function_type_rib);
             }