Fix generics type parameter handling in miri

src/librustc/infer/anon_types/mod.rs

@@ -616,10 +616,9 @@ impl<'cx, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for ReverseMapper<'cx, 'gcx, 'tcx>
                 // during trans.
 
                 let generics = self.tcx.generics_of(def_id);
-                let parent_len = generics.parent_count();
                 let substs = self.tcx.mk_substs(substs.substs.iter().enumerate().map(
                     |(index, &kind)| {
-                        if index < parent_len {
+                        if index < generics.parent_count {
                             // Accommodate missing regions in the parent kinds...
                             self.fold_kind_mapping_missing_regions_to_empty(kind)
                         } else {

src/librustc/ty/subst.rs

@@ -252,7 +252,6 @@ impl<'a, 'gcx, 'tcx> Substs<'tcx> {
         }
 
         for def in &defs.params {
-            assert_eq!(def.index() as usize, substs.len());
             let param = match def {
                 ty::GenericParam::Lifetime(ref lt) => {
                     mk_region(lt, substs).into()
@@ -265,6 +264,7 @@ impl<'a, 'gcx, 'tcx> Substs<'tcx> {
                     mk_type(ty, substs).into()
                 }
             };
+            assert_eq!(def.index() as usize, substs.len());
             substs.push(param);
         }
     }

src/librustc_mir/transform/const_prop.rs

@@ -184,7 +184,7 @@ impl<'b, 'a, 'tcx:'b> ConstPropagator<'b, 'a, 'tcx> {
             // evaluate the promoted and replace the constant with the evaluated result
             Literal::Promoted { index } => {
                 let generics = self.tcx.generics_of(self.source.def_id);
-                if generics.parent_types as usize + generics.types.len() > 0 {
+                if generics.has_type_parameters(self.tcx) {
                     // FIXME: can't handle code with generics
                     return None;
                 }
@@ -295,7 +295,7 @@ impl<'b, 'a, 'tcx:'b> ConstPropagator<'b, 'a, 'tcx> {
                     self.source.def_id
                 };
                 let generics = self.tcx.generics_of(def_id);
-                if generics.parent_types as usize + generics.types.len() > 0 {
+                if generics.has_type_parameters(self.tcx) {
                     // FIXME: can't handle code with generics
                     return None;
                 }
@@ -317,8 +317,7 @@ impl<'b, 'a, 'tcx:'b> ConstPropagator<'b, 'a, 'tcx> {
                     self.source.def_id
                 };
                 let generics = self.tcx.generics_of(def_id);
-                let has_generics = generics.parent_types as usize + generics.types.len() > 0;
-                if has_generics {
+                if generics.has_type_parameters(self.tcx) {
                     // FIXME: can't handle code with generics
                     return None;
                 }

src/librustc_traits/dropck_outlives.rs

@@ -280,7 +280,8 @@ crate fn adt_dtorck_constraint<'a, 'tcx>(
     if def.is_phantom_data() {
         let result = DtorckConstraint {
             outlives: vec![],
-            dtorck_types: vec![tcx.mk_param_from_def(&tcx.generics_of(def_id).types[0])],
+            dtorck_types: vec![tcx.mk_param_from_def(&tcx.generics_of(def_id).types().next()
+                .expect("should be at least one type parameter"))],
             overflows: vec![],
         };
         debug!("dtorck_constraint: {:?} => {:?}", def, result);

src/librustc_trans/back/symbol_export.rs

@@ -117,7 +117,7 @@ fn reachable_non_generics_provider<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 }) => {
                     let def_id = tcx.hir.local_def_id(node_id);
                     let generics = tcx.generics_of(def_id);
-                    if (generics.parent_types == 0 && generics.types.is_empty()) &&
+                    if !generics.has_type_parameters(tcx) &&
                         // Functions marked with #[inline] are only ever translated
                         // with "internal" linkage and are never exported.
                         !Instance::mono(tcx, def_id).def.requires_local(tcx) {

src/librustc_typeck/check/wfcheck.rs

@@ -369,13 +369,13 @@ fn check_where_clauses<'a, 'gcx, 'fcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'gcx>,
 
     let generics = tcx.generics_of(def_id);
     let is_our_default = |def: &ty::TypeParameterDef|
-                            def.has_default && def.index >= generics.parent_count() as u32;
+                            def.has_default && def.index >= generics.parent_count as u32;
 
     // Check that concrete defaults are well-formed. See test `type-check-defaults.rs`.
     // For example this forbids the declaration:
     // struct Foo<T = Vec<[u32]>> { .. }
     // Here the default `Vec<[u32]>` is not WF because `[u32]: Sized` does not hold.
-    for d in generics.types.iter().cloned().filter(is_our_default).map(|p| p.def_id) {
+    for d in generics.types().cloned().filter(is_our_default).map(|p| p.def_id) {
         let ty = fcx.tcx.type_of(d);
         // ignore dependent defaults -- that is, where the default of one type
         // parameter includes another (e.g., <T, U = T>). In those cases, we can't

src/librustc_typeck/collect.rs

@@ -970,10 +970,8 @@ fn generics_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                    .map(|param| (param.def_id, param.index))
                                    .collect();
 
-    let lifetimes: Vec<ty::GenericParam> =
-        regions.into_iter().map(|lt| ty::GenericParam::Lifetime(lt));
-    let types: Vec<ty::GenericParam> =
-        types.into_iter().map(|ty| ty::GenericParam::Type(ty));
+    let lifetimes = regions.into_iter().map(|lt| ty::GenericParam::Lifetime(lt));
+    let types = types.into_iter().map(|ty| ty::GenericParam::Type(ty));
     let params = lifetimes.chain(types).collect();
 
     tcx.alloc_generics(ty::Generics {