Detect incorrect number of lang item generics

3 files changed, 199 insertions, 239 deletions

diff --git a/compiler/rustc_error_codes/src/error_codes/E0152.md b/compiler/rustc_error_codes/src/error_codes/E0152.md
index 120c96b4211..ef17b8b4c75 100644
--- a/compiler/rustc_error_codes/src/error_codes/E0152.md
+++ b/compiler/rustc_error_codes/src/error_codes/E0152.md
@@ -6,7 +6,7 @@ Erroneous code example:
 #![feature(lang_items)]
 
 #[lang = "owned_box"]
-struct Foo; // error: duplicate lang item found: `owned_box`
+struct Foo<T>(T); // error: duplicate lang item found: `owned_box`
 ```
 
 Lang items are already implemented in the standard library. Unless you are
diff --git a/compiler/rustc_hir/src/lang_items.rs b/compiler/rustc_hir/src/lang_items.rs
index 55000ae7e59..b85ed0cb4bb 100644
--- a/compiler/rustc_hir/src/lang_items.rs
+++ b/compiler/rustc_hir/src/lang_items.rs
@@ -38,7 +38,7 @@ macro_rules! expand_group {
 // So you probably just want to nip down to the end.
 macro_rules! language_item_table {
     (
-        $( $(#[$attr:meta])* $variant:ident $($group:expr)?, $module:ident :: $name:ident, $method:ident, $target:expr; )*
+        $( $(#[$attr:meta])* $variant:ident $($group:expr)?, $module:ident :: $name:ident, $method:ident, $target:expr, $generics:expr; )*
     ) => {
 
         enum_from_u32! {
@@ -72,6 +72,12 @@ macro_rules! language_item_table {
                     $( LangItem::$variant => expand_group!($($group)*), )*
                 }
             }
+
+            pub fn required_generics(&self) -> GenericRequirement {
+                match self {
+                    $( LangItem::$variant => $generics, )*
+                }
+            }
         }
 
         /// All of the language items, defined or not.
@@ -165,108 +171,108 @@ where
 }
 
 language_item_table! {
-//  Variant name,            Name,                     Method name,                Target;
-    Bool,                    sym::bool,                bool_impl,                  Target::Impl;
-    Char,                    sym::char,                char_impl,                  Target::Impl;
-    Str,                     sym::str,                 str_impl,                   Target::Impl;
-    Array,                   sym::array,               array_impl,                 Target::Impl;
-    Slice,                   sym::slice,               slice_impl,                 Target::Impl;
-    SliceU8,                 sym::slice_u8,            slice_u8_impl,              Target::Impl;
-    StrAlloc,                sym::str_alloc,           str_alloc_impl,             Target::Impl;
-    SliceAlloc,              sym::slice_alloc,         slice_alloc_impl,           Target::Impl;
-    SliceU8Alloc,            sym::slice_u8_alloc,      slice_u8_alloc_impl,        Target::Impl;
-    ConstPtr,                sym::const_ptr,           const_ptr_impl,             Target::Impl;
-    MutPtr,                  sym::mut_ptr,             mut_ptr_impl,               Target::Impl;
-    ConstSlicePtr,           sym::const_slice_ptr,     const_slice_ptr_impl,       Target::Impl;
-    MutSlicePtr,             sym::mut_slice_ptr,       mut_slice_ptr_impl,         Target::Impl;
-    I8,                      sym::i8,                  i8_impl,                    Target::Impl;
-    I16,                     sym::i16,                 i16_impl,                   Target::Impl;
-    I32,                     sym::i32,                 i32_impl,                   Target::Impl;
-    I64,                     sym::i64,                 i64_impl,                   Target::Impl;
-    I128,                    sym::i128,                i128_impl,                  Target::Impl;
-    Isize,                   sym::isize,               isize_impl,                 Target::Impl;
-    U8,                      sym::u8,                  u8_impl,                    Target::Impl;
-    U16,                     sym::u16,                 u16_impl,                   Target::Impl;
-    U32,                     sym::u32,                 u32_impl,                   Target::Impl;
-    U64,                     sym::u64,                 u64_impl,                   Target::Impl;
-    U128,                    sym::u128,                u128_impl,                  Target::Impl;
-    Usize,                   sym::usize,               usize_impl,                 Target::Impl;
-    F32,                     sym::f32,                 f32_impl,                   Target::Impl;
-    F64,                     sym::f64,                 f64_impl,                   Target::Impl;
-    F32Runtime,              sym::f32_runtime,         f32_runtime_impl,           Target::Impl;
-    F64Runtime,              sym::f64_runtime,         f64_runtime_impl,           Target::Impl;
-
-    Sized,                   sym::sized,               sized_trait,                Target::Trait;
-    Unsize,                  sym::unsize,              unsize_trait,               Target::Trait;
+//  Variant name,            Name,                     Method name,                Target                  Generic requirements;
+    Bool,                    sym::bool,                bool_impl,                  Target::Impl,           GenericRequirement::None;
+    Char,                    sym::char,                char_impl,                  Target::Impl,           GenericRequirement::None;
+    Str,                     sym::str,                 str_impl,                   Target::Impl,           GenericRequirement::None;
+    Array,                   sym::array,               array_impl,                 Target::Impl,           GenericRequirement::None;
+    Slice,                   sym::slice,               slice_impl,                 Target::Impl,           GenericRequirement::None;
+    SliceU8,                 sym::slice_u8,            slice_u8_impl,              Target::Impl,           GenericRequirement::None;
+    StrAlloc,                sym::str_alloc,           str_alloc_impl,             Target::Impl,           GenericRequirement::None;
+    SliceAlloc,              sym::slice_alloc,         slice_alloc_impl,           Target::Impl,           GenericRequirement::None;
+    SliceU8Alloc,            sym::slice_u8_alloc,      slice_u8_alloc_impl,        Target::Impl,           GenericRequirement::None;
+    ConstPtr,                sym::const_ptr,           const_ptr_impl,             Target::Impl,           GenericRequirement::None;
+    MutPtr,                  sym::mut_ptr,             mut_ptr_impl,               Target::Impl,           GenericRequirement::None;
+    ConstSlicePtr,           sym::const_slice_ptr,     const_slice_ptr_impl,       Target::Impl,           GenericRequirement::None;
+    MutSlicePtr,             sym::mut_slice_ptr,       mut_slice_ptr_impl,         Target::Impl,           GenericRequirement::None;
+    I8,                      sym::i8,                  i8_impl,                    Target::Impl,           GenericRequirement::None;
+    I16,                     sym::i16,                 i16_impl,                   Target::Impl,           GenericRequirement::None;
+    I32,                     sym::i32,                 i32_impl,                   Target::Impl,           GenericRequirement::None;
+    I64,                     sym::i64,                 i64_impl,                   Target::Impl,           GenericRequirement::None;
+    I128,                    sym::i128,                i128_impl,                  Target::Impl,           GenericRequirement::None;
+    Isize,                   sym::isize,               isize_impl,                 Target::Impl,           GenericRequirement::None;
+    U8,                      sym::u8,                  u8_impl,                    Target::Impl,           GenericRequirement::None;
+    U16,                     sym::u16,                 u16_impl,                   Target::Impl,           GenericRequirement::None;
+    U32,                     sym::u32,                 u32_impl,                   Target::Impl,           GenericRequirement::None;
+    U64,                     sym::u64,                 u64_impl,                   Target::Impl,           GenericRequirement::None;
+    U128,                    sym::u128,                u128_impl,                  Target::Impl,           GenericRequirement::None;
+    Usize,                   sym::usize,               usize_impl,                 Target::Impl,           GenericRequirement::None;
+    F32,                     sym::f32,                 f32_impl,                   Target::Impl,           GenericRequirement::None;
+    F64,                     sym::f64,                 f64_impl,                   Target::Impl,           GenericRequirement::None;
+    F32Runtime,              sym::f32_runtime,         f32_runtime_impl,           Target::Impl,           GenericRequirement::None;
+    F64Runtime,              sym::f64_runtime,         f64_runtime_impl,           Target::Impl,           GenericRequirement::None;
+
+    Sized,                   sym::sized,               sized_trait,                Target::Trait,          GenericRequirement::Exact(0);
+    Unsize,                  sym::unsize,              unsize_trait,               Target::Trait,          GenericRequirement::Minimum(1);
     /// Trait injected by `#[derive(PartialEq)]`, (i.e. "Partial EQ").
-    StructuralPeq,           sym::structural_peq,      structural_peq_trait,       Target::Trait;
+    StructuralPeq,           sym::structural_peq,      structural_peq_trait,       Target::Trait,          GenericRequirement::None;
     /// Trait injected by `#[derive(Eq)]`, (i.e. "Total EQ"; no, I will not apologize).
-    StructuralTeq,           sym::structural_teq,      structural_teq_trait,       Target::Trait;
-    Copy,                    sym::copy,                copy_trait,                 Target::Trait;
-    Clone,                   sym::clone,               clone_trait,                Target::Trait;
-    Sync,                    sym::sync,                sync_trait,                 Target::Trait;
-    DiscriminantKind,        sym::discriminant_kind,   discriminant_kind_trait,    Target::Trait;
+    StructuralTeq,           sym::structural_teq,      structural_teq_trait,       Target::Trait,          GenericRequirement::None;
+    Copy,                    sym::copy,                copy_trait,                 Target::Trait,          GenericRequirement::Exact(0);
+    Clone,                   sym::clone,               clone_trait,                Target::Trait,          GenericRequirement::None;
+    Sync,                    sym::sync,                sync_trait,                 Target::Trait,          GenericRequirement::Exact(0);
+    DiscriminantKind,        sym::discriminant_kind,   discriminant_kind_trait,    Target::Trait,          GenericRequirement::None;
     /// The associated item of the [`DiscriminantKind`] trait.
-    Discriminant,            sym::discriminant_type,   discriminant_type,          Target::AssocTy;
-
-    PointeeTrait,            sym::pointee_trait,       pointee_trait,              Target::Trait;
-    Metadata,                sym::metadata_type,       metadata_type,              Target::AssocTy;
-    DynMetadata,             sym::dyn_metadata,        dyn_metadata,               Target::Struct;
-
-    Freeze,                  sym::freeze,              freeze_trait,               Target::Trait;
-
-    Drop,                    sym::drop,                drop_trait,                 Target::Trait;
-
-    CoerceUnsized,           sym::coerce_unsized,      coerce_unsized_trait,       Target::Trait;
-    DispatchFromDyn,         sym::dispatch_from_dyn,   dispatch_from_dyn_trait,    Target::Trait;
-
-    Add(Op),                 sym::add,                 add_trait,                  Target::Trait;
-    Sub(Op),                 sym::sub,                 sub_trait,                  Target::Trait;
-    Mul(Op),                 sym::mul,                 mul_trait,                  Target::Trait;
-    Div(Op),                 sym::div,                 div_trait,                  Target::Trait;
-    Rem(Op),                 sym::rem,                 rem_trait,                  Target::Trait;
-    Neg(Op),                 sym::neg,                 neg_trait,                  Target::Trait;
-    Not(Op),                 sym::not,                 not_trait,                  Target::Trait;
-    BitXor(Op),              sym::bitxor,              bitxor_trait,               Target::Trait;
-    BitAnd(Op),              sym::bitand,              bitand_trait,               Target::Trait;
-    BitOr(Op),               sym::bitor,               bitor_trait,                Target::Trait;
-    Shl(Op),                 sym::shl,                 shl_trait,                  Target::Trait;
-    Shr(Op),                 sym::shr,                 shr_trait,                  Target::Trait;
-    AddAssign(Op),           sym::add_assign,          add_assign_trait,           Target::Trait;
-    SubAssign(Op),           sym::sub_assign,          sub_assign_trait,           Target::Trait;
-    MulAssign(Op),           sym::mul_assign,          mul_assign_trait,           Target::Trait;
-    DivAssign(Op),           sym::div_assign,          div_assign_trait,           Target::Trait;
-    RemAssign(Op),           sym::rem_assign,          rem_assign_trait,           Target::Trait;
-    BitXorAssign(Op),        sym::bitxor_assign,       bitxor_assign_trait,        Target::Trait;
-    BitAndAssign(Op),        sym::bitand_assign,       bitand_assign_trait,        Target::Trait;
-    BitOrAssign(Op),         sym::bitor_assign,        bitor_assign_trait,         Target::Trait;
-    ShlAssign(Op),           sym::shl_assign,          shl_assign_trait,           Target::Trait;
-    ShrAssign(Op),           sym::shr_assign,          shr_assign_trait,           Target::Trait;
-    Index(Op),               sym::index,               index_trait,                Target::Trait;
-    IndexMut(Op),            sym::index_mut,           index_mut_trait,            Target::Trait;
-
-    UnsafeCell,              sym::unsafe_cell,         unsafe_cell_type,           Target::Struct;
-    VaList,                  sym::va_list,             va_list,                    Target::Struct;
-
-    Deref,                   sym::deref,               deref_trait,                Target::Trait;
-    DerefMut,                sym::deref_mut,           deref_mut_trait,            Target::Trait;
-    DerefTarget,             sym::deref_target,        deref_target,               Target::AssocTy;
-    Receiver,                sym::receiver,            receiver_trait,             Target::Trait;
-
-    Fn,                      kw::Fn,                   fn_trait,                   Target::Trait;
-    FnMut,                   sym::fn_mut,              fn_mut_trait,               Target::Trait;
-    FnOnce,                  sym::fn_once,             fn_once_trait,              Target::Trait;
-
-    FnOnceOutput,            sym::fn_once_output,      fn_once_output,             Target::AssocTy;
-
-    Future,                  sym::future_trait,        future_trait,               Target::Trait;
-    GeneratorState,          sym::generator_state,     gen_state,                  Target::Enum;
-    Generator,               sym::generator,           gen_trait,                  Target::Trait;
-    Unpin,                   sym::unpin,               unpin_trait,                Target::Trait;
-    Pin,                     sym::pin,                 pin_type,                   Target::Struct;
-
-    PartialEq,               sym::eq,                  eq_trait,                   Target::Trait;
-    PartialOrd,              sym::partial_ord,         partial_ord_trait,          Target::Trait;
+    Discriminant,            sym::discriminant_type,   discriminant_type,          Target::AssocTy,        GenericRequirement::None;
+
+    PointeeTrait,            sym::pointee_trait,       pointee_trait,              Target::Trait,          GenericRequirement::None;
+    Metadata,                sym::metadata_type,       metadata_type,              Target::AssocTy,        GenericRequirement::None;
+    DynMetadata,             sym::dyn_metadata,        dyn_metadata,               Target::Struct,         GenericRequirement::None;
+
+    Freeze,                  sym::freeze,              freeze_trait,               Target::Trait,          GenericRequirement::Exact(0);
+
+    Drop,                    sym::drop,                drop_trait,                 Target::Trait,          GenericRequirement::None;
+
+    CoerceUnsized,           sym::coerce_unsized,      coerce_unsized_trait,       Target::Trait,          GenericRequirement::Minimum(1);
+    DispatchFromDyn,         sym::dispatch_from_dyn,   dispatch_from_dyn_trait,    Target::Trait,          GenericRequirement::Minimum(1);
+
+    Add(Op),                 sym::add,                 add_trait,                  Target::Trait,          GenericRequirement::Exact(1);
+    Sub(Op),                 sym::sub,                 sub_trait,                  Target::Trait,          GenericRequirement::Exact(1);
+    Mul(Op),                 sym::mul,                 mul_trait,                  Target::Trait,          GenericRequirement::Exact(1);
+    Div(Op),                 sym::div,                 div_trait,                  Target::Trait,          GenericRequirement::Exact(1);
+    Rem(Op),                 sym::rem,                 rem_trait,                  Target::Trait,          GenericRequirement::Exact(1);
+    Neg(Op),                 sym::neg,                 neg_trait,                  Target::Trait,          GenericRequirement::Exact(0);
+    Not(Op),                 sym::not,                 not_trait,                  Target::Trait,          GenericRequirement::Exact(0);
+    BitXor(Op),              sym::bitxor,              bitxor_trait,               Target::Trait,          GenericRequirement::Exact(1);
+    BitAnd(Op),              sym::bitand,              bitand_trait,               Target::Trait,          GenericRequirement::Exact(1);
+    BitOr(Op),               sym::bitor,               bitor_trait,                Target::Trait,          GenericRequirement::Exact(1);
+    Shl(Op),                 sym::shl,                 shl_trait,                  Target::Trait,          GenericRequirement::Exact(1);
+    Shr(Op),                 sym::shr,                 shr_trait,                  Target::Trait,          GenericRequirement::Exact(1);
+    AddAssign(Op),           sym::add_assign,          add_assign_trait,           Target::Trait,          GenericRequirement::Exact(1);
+    SubAssign(Op),           sym::sub_assign,          sub_assign_trait,           Target::Trait,          GenericRequirement::Exact(1);
+    MulAssign(Op),           sym::mul_assign,          mul_assign_trait,           Target::Trait,          GenericRequirement::Exact(1);
+    DivAssign(Op),           sym::div_assign,          div_assign_trait,           Target::Trait,          GenericRequirement::Exact(1);
+    RemAssign(Op),           sym::rem_assign,          rem_assign_trait,           Target::Trait,          GenericRequirement::Exact(1);
+    BitXorAssign(Op),        sym::bitxor_assign,       bitxor_assign_trait,        Target::Trait,          GenericRequirement::Exact(1);
+    BitAndAssign(Op),        sym::bitand_assign,       bitand_assign_trait,        Target::Trait,          GenericRequirement::Exact(1);
+    BitOrAssign(Op),         sym::bitor_assign,        bitor_assign_trait,         Target::Trait,          GenericRequirement::Exact(1);
+    ShlAssign(Op),           sym::shl_assign,          shl_assign_trait,           Target::Trait,          GenericRequirement::Exact(1);
+    ShrAssign(Op),           sym::shr_assign,          shr_assign_trait,           Target::Trait,          GenericRequirement::Exact(1);
+    Index(Op),               sym::index,               index_trait,                Target::Trait,          GenericRequirement::Exact(1);
+    IndexMut(Op),            sym::index_mut,           index_mut_trait,            Target::Trait,          GenericRequirement::Exact(1);
+
+    UnsafeCell,              sym::unsafe_cell,         unsafe_cell_type,           Target::Struct,         GenericRequirement::None;
+    VaList,                  sym::va_list,             va_list,                    Target::Struct,         GenericRequirement::None;
+
+    Deref,                   sym::deref,               deref_trait,                Target::Trait,          GenericRequirement::Exact(0);
+    DerefMut,                sym::deref_mut,           deref_mut_trait,            Target::Trait,          GenericRequirement::Exact(0);
+    DerefTarget,             sym::deref_target,        deref_target,               Target::AssocTy,        GenericRequirement::None;
+    Receiver,                sym::receiver,            receiver_trait,             Target::Trait,          GenericRequirement::None;
+
+    Fn,                      kw::Fn,                   fn_trait,                   Target::Trait,          GenericRequirement::Exact(1);
+    FnMut,                   sym::fn_mut,              fn_mut_trait,               Target::Trait,          GenericRequirement::Exact(1);
+    FnOnce,                  sym::fn_once,             fn_once_trait,              Target::Trait,          GenericRequirement::Exact(1);
+
+    FnOnceOutput,            sym::fn_once_output,      fn_once_output,             Target::AssocTy,        GenericRequirement::None;
+
+    Future,                  sym::future_trait,        future_trait,               Target::Trait,          GenericRequirement::Exact(0);
+    GeneratorState,          sym::generator_state,     gen_state,                  Target::Enum,           GenericRequirement::None;
+    Generator,               sym::generator,           gen_trait,                  Target::Trait,          GenericRequirement::Minimum(1);
+    Unpin,                   sym::unpin,               unpin_trait,                Target::Trait,          GenericRequirement::None;
+    Pin,                     sym::pin,                 pin_type,                   Target::Struct,         GenericRequirement::None;
+
+    PartialEq,               sym::eq,                  eq_trait,                   Target::Trait,          GenericRequirement::Exact(1);
+    PartialOrd,              sym::partial_ord,         partial_ord_trait,          Target::Trait,          GenericRequirement::Exact(1);
 
     // A number of panic-related lang items. The `panic` item corresponds to divide-by-zero and
     // various panic cases with `match`. The `panic_bounds_check` item is for indexing arrays.
@@ -275,80 +281,86 @@ language_item_table! {
     // in the sense that a crate is not required to have it defined to use it, but a final product
     // is required to define it somewhere. Additionally, there are restrictions on crates that use
     // a weak lang item, but do not have it defined.
-    Panic,                   sym::panic,               panic_fn,                   Target::Fn;
-    PanicFmt,                sym::panic_fmt,           panic_fmt,                  Target::Fn;
-    PanicStr,                sym::panic_str,           panic_str,                  Target::Fn;
-    ConstPanicFmt,           sym::const_panic_fmt,     const_panic_fmt,            Target::Fn;
-    PanicBoundsCheck,        sym::panic_bounds_check,  panic_bounds_check_fn,      Target::Fn;
-    PanicInfo,               sym::panic_info,          panic_info,                 Target::Struct;
-    PanicLocation,           sym::panic_location,      panic_location,             Target::Struct;
-    PanicImpl,               sym::panic_impl,          panic_impl,                 Target::Fn;
+    Panic,                   sym::panic,               panic_fn,                   Target::Fn,             GenericRequirement::None;
+    PanicFmt,                sym::panic_fmt,           panic_fmt,                  Target::Fn,             GenericRequirement::None;
+    PanicStr,                sym::panic_str,           panic_str,                  Target::Fn,             GenericRequirement::None;
+    ConstPanicFmt,           sym::const_panic_fmt,     const_panic_fmt,            Target::Fn,             GenericRequirement::None;
+    PanicBoundsCheck,        sym::panic_bounds_check,  panic_bounds_check_fn,      Target::Fn,             GenericRequirement::None;
+    PanicInfo,               sym::panic_info,          panic_info,                 Target::Struct,         GenericRequirement::None;
+    PanicLocation,           sym::panic_location,      panic_location,             Target::Struct,         GenericRequirement::None;
+    PanicImpl,               sym::panic_impl,          panic_impl,                 Target::Fn,             GenericRequirement::None;
     /// libstd panic entry point. Necessary for const eval to be able to catch it
-    BeginPanic,              sym::begin_panic,         begin_panic_fn,             Target::Fn;
-    BeginPanicFmt,           sym::begin_panic_fmt,     begin_panic_fmt,            Target::Fn;
+    BeginPanic,              sym::begin_panic,         begin_panic_fn,             Target::Fn,             GenericRequirement::None;
+    BeginPanicFmt,           sym::begin_panic_fmt,     begin_panic_fmt,            Target::Fn,             GenericRequirement::None;
 
-    ExchangeMalloc,          sym::exchange_malloc,     exchange_malloc_fn,         Target::Fn;
-    BoxFree,                 sym::box_free,            box_free_fn,                Target::Fn;
-    DropInPlace,             sym::drop_in_place,       drop_in_place_fn,           Target::Fn;
-    Oom,                     sym::oom,                 oom,                        Target::Fn;
-    AllocLayout,             sym::alloc_layout,        alloc_layout,               Target::Struct;
+    ExchangeMalloc,          sym::exchange_malloc,     exchange_malloc_fn,         Target::Fn,             GenericRequirement::None;
+    BoxFree,                 sym::box_free,            box_free_fn,                Target::Fn,             GenericRequirement::Minimum(1);
+    DropInPlace,             sym::drop_in_place,       drop_in_place_fn,           Target::Fn,             GenericRequirement::Minimum(1);
+    Oom,                     sym::oom,                 oom,                        Target::Fn,             GenericRequirement::None;
+    AllocLayout,             sym::alloc_layout,        alloc_layout,               Target::Struct,         GenericRequirement::None;
 
-    Start,                   sym::start,               start_fn,                   Target::Fn;
+    Start,                   sym::start,               start_fn,                   Target::Fn,             GenericRequirement::None;
 
-    EhPersonality,           sym::eh_personality,      eh_personality,             Target::Fn;
-    EhCatchTypeinfo,         sym::eh_catch_typeinfo,   eh_catch_typeinfo,          Target::Static;
+    EhPersonality,           sym::eh_personality,      eh_personality,             Target::Fn,             GenericRequirement::None;
+    EhCatchTypeinfo,         sym::eh_catch_typeinfo,   eh_catch_typeinfo,          Target::Static,         GenericRequirement::None;
 
-    OwnedBox,                sym::owned_box,           owned_box,                  Target::Struct;
+    OwnedBox,                sym::owned_box,           owned_box,                  Target::Struct,         GenericRequirement::Minimum(1);
 
-    PhantomData,             sym::phantom_data,        phantom_data,               Target::Struct;
+    PhantomData,             sym::phantom_data,        phantom_data,               Target::Struct,         GenericRequirement::Exact(1);
 
-    ManuallyDrop,            sym::manually_drop,       manually_drop,              Target::Struct;
+    ManuallyDrop,            sym::manually_drop,       manually_drop,              Target::Struct,         GenericRequirement::None;
 
-    MaybeUninit,             sym::maybe_uninit,        maybe_uninit,               Target::Union;
+    MaybeUninit,             sym::maybe_uninit,        maybe_uninit,               Target::Union,          GenericRequirement::None;
 
     /// Align offset for stride != 1; must not panic.
-    AlignOffset,             sym::align_offset,        align_offset_fn,            Target::Fn;
+    AlignOffset,             sym::align_offset,        align_offset_fn,            Target::Fn,             GenericRequirement::None;
 
-    Termination,             sym::termination,         termination,                Target::Trait;
+    Termination,             sym::termination,         termination,                Target::Trait,          GenericRequirement::None;
 
-    Try,                     sym::Try,                 try_trait,                  Target::Trait;
+    Try,                     sym::Try,                 try_trait,                  Target::Trait,          GenericRequirement::None;
 
-    SliceLen,                sym::slice_len_fn,        slice_len_fn,               Target::Method(MethodKind::Inherent);
+    SliceLen,                sym::slice_len_fn,        slice_len_fn,               Target::Method(MethodKind::Inherent), GenericRequirement::None;
 
     // Language items from AST lowering
-    TryTraitFromResidual,    sym::from_residual,       from_residual_fn,           Target::Method(MethodKind::Trait { body: false });
-    TryTraitFromOutput,      sym::from_output,         from_output_fn,             Target::Method(MethodKind::Trait { body: false });
-    TryTraitBranch,          sym::branch,              branch_fn,                  Target::Method(MethodKind::Trait { body: false });
+    TryTraitFromResidual,    sym::from_residual,       from_residual_fn,           Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
+    TryTraitFromOutput,      sym::from_output,         from_output_fn,             Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
+    TryTraitBranch,          sym::branch,              branch_fn,                  Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
+
+    PollReady,               sym::Ready,               poll_ready_variant,         Target::Variant,        GenericRequirement::None;
+    PollPending,             sym::Pending,             poll_pending_variant,       Target::Variant,        GenericRequirement::None;
 
-    PollReady,               sym::Ready,               poll_ready_variant,         Target::Variant;
-    PollPending,             sym::Pending,             poll_pending_variant,       Target::Variant;
+    FromGenerator,           sym::from_generator,      from_generator_fn,          Target::Fn,             GenericRequirement::None;
+    GetContext,              sym::get_context,         get_context_fn,             Target::Fn,             GenericRequirement::None;
 
-    FromGenerator,           sym::from_generator,      from_generator_fn,          Target::Fn;
-    GetContext,              sym::get_context,         get_context_fn,             Target::Fn;
+    FuturePoll,              sym::poll,                future_poll_fn,             Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
 
-    FuturePoll,              sym::poll,                future_poll_fn,             Target::Method(MethodKind::Trait { body: false });
+    FromFrom,                sym::from,                from_fn,                    Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
 
-    FromFrom,                sym::from,                from_fn,                    Target::Method(MethodKind::Trait { body: false });
+    OptionSome,              sym::Some,                option_some_variant,        Target::Variant,        GenericRequirement::None;
+    OptionNone,              sym::None,                option_none_variant,        Target::Variant,        GenericRequirement::None;
 
-    OptionSome,              sym::Some,                option_some_variant,        Target::Variant;
-    OptionNone,              sym::None,                option_none_variant,        Target::Variant;
+    ResultOk,                sym::Ok,                  result_ok_variant,          Target::Variant,        GenericRequirement::None;
+    ResultErr,               sym::Err,                 result_err_variant,         Target::Variant,        GenericRequirement::None;
 
-    ResultOk,                sym::Ok,                  result_ok_variant,          Target::Variant;
-    ResultErr,               sym::Err,                 result_err_variant,         Target::Variant;
+    ControlFlowContinue,     sym::Continue,            cf_continue_variant,        Target::Variant,        GenericRequirement::None;
+    ControlFlowBreak,        sym::Break,               cf_break_variant,           Target::Variant,        GenericRequirement::None;
 
-    ControlFlowContinue,     sym::Continue,            cf_continue_variant,        Target::Variant;
-    ControlFlowBreak,        sym::Break,               cf_break_variant,           Target::Variant;
+    IntoIterIntoIter,        sym::into_iter,           into_iter_fn,               Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
+    IteratorNext,            sym::next,                next_fn,                    Target::Method(MethodKind::Trait { body: false}), GenericRequirement::None;
 
-    IntoIterIntoIter,        sym::into_iter,           into_iter_fn,               Target::Method(MethodKind::Trait { body: false });
-    IteratorNext,            sym::next,                next_fn,                    Target::Method(MethodKind::Trait { body: false});
+    PinNewUnchecked,         sym::new_unchecked,       new_unchecked_fn,           Target::Method(MethodKind::Inherent), GenericRequirement::None;
 
-    PinNewUnchecked,         sym::new_unchecked,       new_unchecked_fn,           Target::Method(MethodKind::Inherent);
+    RangeFrom,               sym::RangeFrom,           range_from_struct,          Target::Struct,         GenericRequirement::None;
+    RangeFull,               sym::RangeFull,           range_full_struct,          Target::Struct,         GenericRequirement::None;
+    RangeInclusiveStruct,    sym::RangeInclusive,      range_inclusive_struct,     Target::Struct,         GenericRequirement::None;
+    RangeInclusiveNew,       sym::range_inclusive_new, range_inclusive_new_method, Target::Method(MethodKind::Inherent), GenericRequirement::None;
+    Range,                   sym::Range,               range_struct,               Target::Struct,         GenericRequirement::None;
+    RangeToInclusive,        sym::RangeToInclusive,    range_to_inclusive_struct,  Target::Struct,         GenericRequirement::None;
+    RangeTo,                 sym::RangeTo,             range_to_struct,            Target::Struct,         GenericRequirement::None;
+}
 
-    RangeFrom,               sym::RangeFrom,           range_from_struct,          Target::Struct;
-    RangeFull,               sym::RangeFull,           range_full_struct,          Target::Struct;
-    RangeInclusiveStruct,    sym::RangeInclusive,      range_inclusive_struct,     Target::Struct;
-    RangeInclusiveNew,       sym::range_inclusive_new, range_inclusive_new_method, Target::Method(MethodKind::Inherent);
-    Range,                   sym::Range,               range_struct,               Target::Struct;
-    RangeToInclusive,        sym::RangeToInclusive,    range_to_inclusive_struct,  Target::Struct;
-    RangeTo,                 sym::RangeTo,             range_to_struct,            Target::Struct;
+pub enum GenericRequirement {
+    None,
+    Minimum(usize),
+    Exact(usize),
 }
diff --git a/compiler/rustc_passes/src/lang_items.rs b/compiler/rustc_passes/src/lang_items.rs
index 3a88d1932a8..9d449589b16 100644
--- a/compiler/rustc_passes/src/lang_items.rs
+++ b/compiler/rustc_passes/src/lang_items.rs
@@ -17,7 +17,7 @@ use rustc_errors::{pluralize, struct_span_err};
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_hir::itemlikevisit::ItemLikeVisitor;
-use rustc_hir::lang_items::{extract, ITEM_REFS};
+use rustc_hir::lang_items::{extract, GenericRequirement, ITEM_REFS};
 use rustc_hir::{HirId, LangItem, LanguageItems, Target};
 use rustc_span::Span;
 
@@ -182,97 +182,39 @@ impl LanguageItemCollector<'tcx> {
     }
 
     // Like collect_item() above, but also checks whether the lang item is declared
-    // with the right number of generic arguments if it is a trait.
+    // with the right number of generic arguments.
     fn collect_item_extended(&mut self, item_index: usize, hir_id: HirId, span: Span) {
         let item_def_id = self.tcx.hir().local_def_id(hir_id).to_def_id();
         let lang_item = LangItem::from_u32(item_index as u32).unwrap();
         let name = lang_item.name();
 
-        self.collect_item(item_index, item_def_id);
-
         // Now check whether the lang_item has the expected number of generic
-        // arguments if it is a trait. Generally speaking, binary and indexing
-        // operations have one (for the RHS/index), unary operations have none,
-        // and the rest also have none except for the closure traits (one for
-        // the argument list), generators (one for the resume argument),
-        // ordering/equality relations (one for the RHS), and various conversion
-        // traits.
-
-        let expected_num = match lang_item {
-            // Binary operations
-            LangItem::Add
-            | LangItem::Sub
-            | LangItem::Mul
-            | LangItem::Div
-            | LangItem::Rem
-            | LangItem::BitXor
-            | LangItem::BitAnd
-            | LangItem::BitOr
-            | LangItem::Shl
-            | LangItem::Shr
-            | LangItem::AddAssign
-            | LangItem::SubAssign
-            | LangItem::MulAssign
-            | LangItem::DivAssign
-            | LangItem::RemAssign
-            | LangItem::BitXorAssign
-            | LangItem::BitAndAssign
-            | LangItem::BitOrAssign
-            | LangItem::ShlAssign
-            | LangItem::ShrAssign
-            | LangItem::Index
-            | LangItem::IndexMut
-
-            // Miscellaneous
-            | LangItem::Unsize
-            | LangItem::CoerceUnsized
-            | LangItem::DispatchFromDyn
-            | LangItem::Fn
-            | LangItem::FnMut
-            | LangItem::FnOnce
-            | LangItem::Generator
-            | LangItem::PartialEq
-            | LangItem::PartialOrd
-                => Some(1),
-
-            // Unary operations
-            LangItem::Neg
-            | LangItem::Not
-
-            // Miscellaneous
-            | LangItem::Deref
-            | LangItem::DerefMut
-            | LangItem::Sized
-            | LangItem::StructuralPeq
-            | LangItem::StructuralTeq
-            | LangItem::Copy
-            | LangItem::Clone
-            | LangItem::Sync
-            | LangItem::DiscriminantKind
-            | LangItem::PointeeTrait
-            | LangItem::Freeze
-            | LangItem::Drop
-            | LangItem::Receiver
-            | LangItem::Future
-            | LangItem::Unpin
-            | LangItem::Termination
-            | LangItem::Try
-                => Some(0),
+        // arguments. Generally speaking, binary and indexing operations have
+        // one (for the RHS/index), unary operations have none, the closure
+        // traits have one for the argument list, generators have one for the
+        // resume argument, and ordering/equality relations have one for the RHS
+        // Some other types like Box and various functions like drop_in_place
+        // have minimum requirements.
 
-            // Not a trait
-            _ => None,
-        };
+        if let hir::Node::Item(hir::Item { kind, span: item_span, .. }) = self.tcx.hir().get(hir_id)
+        {
+            let (actual_num, generics_span) = match kind.generics() {
+                Some(generics) => (generics.params.len(), generics.span),
+                None => (0, *item_span),
+            };
 
-        if let Some(expected_num) = expected_num {
-            let (actual_num, generics_span) = match self.tcx.hir().get(hir_id) {
-                hir::Node::Item(hir::Item {
-                    kind: hir::ItemKind::Trait(_, _, generics, ..),
-                    ..
-                }) => (generics.params.len(), generics.span),
-                _ => bug!("op/index/deref lang item target is not a trait: {:?}", lang_item),
+            let required = match lang_item.required_generics() {
+                GenericRequirement::Exact(num) if num != actual_num => {
+                    Some((format!("{}", num), pluralize!(num)))
+                }
+                GenericRequirement::Minimum(num) if actual_num < num => {
+                    Some((format!("at least {}", num), pluralize!(num)))
+                }
+                // If the number matches, or there is no requirement, handle it normally
+                _ => None,
             };
 
-            if expected_num != actual_num {
+            if let Some((range_str, pluralized)) = required {
                 // We are issuing E0718 "incorrect target" here, because while the
                 // item kind of the target is correct, the target is still wrong
                 // because of the wrong number of generic arguments.
@@ -280,23 +222,29 @@ impl LanguageItemCollector<'tcx> {
                     self.tcx.sess,
                     span,
                     E0718,
-                    "`{}` language item must be applied to a trait with {} generic argument{}",
+                    "`{}` language item must be applied to a {} with {} generic argument{}",
                     name,
-                    expected_num,
-                    pluralize!(expected_num)
+                    kind.descr(),
+                    range_str,
+                    pluralized,
                 )
                 .span_label(
                     generics_span,
                     format!(
-                        "this trait has {} generic argument{}, not {}",
+                        "this {} has {} generic argument{}",
+                        kind.descr(),
                         actual_num,
                         pluralize!(actual_num),
-                        expected_num
                     ),
                 )
                 .emit();
+
+                // return early to not collect the lang item
+                return;
             }
         }
+
+        self.collect_item(item_index, item_def_id);
     }
 }