diff --git a/src/etc/lldb_lookup.py b/src/etc/lldb_lookup.py
index abbd802dcdd12..f4ea904b7f50b 100644
--- a/src/etc/lldb_lookup.py
+++ b/src/etc/lldb_lookup.py
@@ -5,11 +5,11 @@
 
 
 # BACKCOMPAT: rust 1.35
-def is_hashbrown_hashmap(hash_map):
+def is_hashbrown_hashmap(hash_map: lldb.SBValue) -> bool:
     return len(hash_map.type.fields) == 1
 
 
-def classify_rust_type(type):
+def classify_rust_type(type: lldb.SBType) -> str:
     type_class = type.GetTypeClass()
     if type_class == lldb.eTypeClassStruct:
         return classify_struct(type.name, type.fields)
@@ -19,106 +19,104 @@ def classify_rust_type(type):
     return RustType.OTHER
 
 
-def summary_lookup(valobj, dict):
-    # type: (SBValue, dict) -> str
+def summary_lookup(valobj: lldb.SBValue, _dict: LLDBOpaque) -> str:
     """Returns the summary provider for the given value"""
     rust_type = classify_rust_type(valobj.GetType())
 
     if rust_type == RustType.STD_STRING:
-        return StdStringSummaryProvider(valobj, dict)
+        return StdStringSummaryProvider(valobj, _dict)
     if rust_type == RustType.STD_OS_STRING:
-        return StdOsStringSummaryProvider(valobj, dict)
+        return StdOsStringSummaryProvider(valobj, _dict)
     if rust_type == RustType.STD_STR:
-        return StdStrSummaryProvider(valobj, dict)
+        return StdStrSummaryProvider(valobj, _dict)
 
     if rust_type == RustType.STD_VEC:
-        return SizeSummaryProvider(valobj, dict)
+        return SizeSummaryProvider(valobj, _dict)
     if rust_type == RustType.STD_VEC_DEQUE:
-        return SizeSummaryProvider(valobj, dict)
+        return SizeSummaryProvider(valobj, _dict)
     if rust_type == RustType.STD_SLICE:
-        return SizeSummaryProvider(valobj, dict)
+        return SizeSummaryProvider(valobj, _dict)
 
     if rust_type == RustType.STD_HASH_MAP:
-        return SizeSummaryProvider(valobj, dict)
+        return SizeSummaryProvider(valobj, _dict)
     if rust_type == RustType.STD_HASH_SET:
-        return SizeSummaryProvider(valobj, dict)
+        return SizeSummaryProvider(valobj, _dict)
 
     if rust_type == RustType.STD_RC:
-        return StdRcSummaryProvider(valobj, dict)
+        return StdRcSummaryProvider(valobj, _dict)
     if rust_type == RustType.STD_ARC:
-        return StdRcSummaryProvider(valobj, dict)
+        return StdRcSummaryProvider(valobj, _dict)
 
     if rust_type == RustType.STD_REF:
-        return StdRefSummaryProvider(valobj, dict)
+        return StdRefSummaryProvider(valobj, _dict)
     if rust_type == RustType.STD_REF_MUT:
-        return StdRefSummaryProvider(valobj, dict)
+        return StdRefSummaryProvider(valobj, _dict)
     if rust_type == RustType.STD_REF_CELL:
-        return StdRefSummaryProvider(valobj, dict)
+        return StdRefSummaryProvider(valobj, _dict)
 
     if rust_type == RustType.STD_NONZERO_NUMBER:
-        return StdNonZeroNumberSummaryProvider(valobj, dict)
+        return StdNonZeroNumberSummaryProvider(valobj, _dict)
 
     if rust_type == RustType.STD_PATHBUF:
-        return StdPathBufSummaryProvider(valobj, dict)
+        return StdPathBufSummaryProvider(valobj, _dict)
     if rust_type == RustType.STD_PATH:
-        return StdPathSummaryProvider(valobj, dict)
+        return StdPathSummaryProvider(valobj, _dict)
 
     return ""
 
 
-def synthetic_lookup(valobj, dict):
-    # type: (SBValue, dict) -> object
+def synthetic_lookup(valobj: lldb.SBValue, _dict: LLDBOpaque) -> object:
     """Returns the synthetic provider for the given value"""
     rust_type = classify_rust_type(valobj.GetType())
 
     if rust_type == RustType.STRUCT:
-        return StructSyntheticProvider(valobj, dict)
+        return StructSyntheticProvider(valobj, _dict)
     if rust_type == RustType.STRUCT_VARIANT:
-        return StructSyntheticProvider(valobj, dict, is_variant=True)
+        return StructSyntheticProvider(valobj, _dict, is_variant=True)
     if rust_type == RustType.TUPLE:
-        return TupleSyntheticProvider(valobj, dict)
+        return TupleSyntheticProvider(valobj, _dict)
     if rust_type == RustType.TUPLE_VARIANT:
-        return TupleSyntheticProvider(valobj, dict, is_variant=True)
+        return TupleSyntheticProvider(valobj, _dict, is_variant=True)
     if rust_type == RustType.EMPTY:
-        return EmptySyntheticProvider(valobj, dict)
+        return EmptySyntheticProvider(valobj, _dict)
     if rust_type == RustType.REGULAR_ENUM:
         discriminant = valobj.GetChildAtIndex(0).GetChildAtIndex(0).GetValueAsUnsigned()
-        return synthetic_lookup(valobj.GetChildAtIndex(discriminant), dict)
+        return synthetic_lookup(valobj.GetChildAtIndex(discriminant), _dict)
     if rust_type == RustType.SINGLETON_ENUM:
-        return synthetic_lookup(valobj.GetChildAtIndex(0), dict)
+        return synthetic_lookup(valobj.GetChildAtIndex(0), _dict)
     if rust_type == RustType.ENUM:
-        return ClangEncodedEnumProvider(valobj, dict)
+        return ClangEncodedEnumProvider(valobj, _dict)
     if rust_type == RustType.STD_VEC:
-        return StdVecSyntheticProvider(valobj, dict)
+        return StdVecSyntheticProvider(valobj, _dict)
     if rust_type == RustType.STD_VEC_DEQUE:
-        return StdVecDequeSyntheticProvider(valobj, dict)
+        return StdVecDequeSyntheticProvider(valobj, _dict)
     if rust_type == RustType.STD_SLICE or rust_type == RustType.STD_STR:
-        return StdSliceSyntheticProvider(valobj, dict)
+        return StdSliceSyntheticProvider(valobj, _dict)
 
     if rust_type == RustType.STD_HASH_MAP:
         if is_hashbrown_hashmap(valobj):
-            return StdHashMapSyntheticProvider(valobj, dict)
+            return StdHashMapSyntheticProvider(valobj, _dict)
         else:
-            return StdOldHashMapSyntheticProvider(valobj, dict)
+            return StdOldHashMapSyntheticProvider(valobj, _dict)
     if rust_type == RustType.STD_HASH_SET:
         hash_map = valobj.GetChildAtIndex(0)
         if is_hashbrown_hashmap(hash_map):
-            return StdHashMapSyntheticProvider(valobj, dict, show_values=False)
+            return StdHashMapSyntheticProvider(valobj, _dict, show_values=False)
         else:
-            return StdOldHashMapSyntheticProvider(hash_map, dict, show_values=False)
+            return StdOldHashMapSyntheticProvider(hash_map, _dict, show_values=False)
 
     if rust_type == RustType.STD_RC:
-        return StdRcSyntheticProvider(valobj, dict)
+        return StdRcSyntheticProvider(valobj, _dict)
     if rust_type == RustType.STD_ARC:
-        return StdRcSyntheticProvider(valobj, dict, is_atomic=True)
+        return StdRcSyntheticProvider(valobj, _dict, is_atomic=True)
 
     if rust_type == RustType.STD_CELL:
-        return StdCellSyntheticProvider(valobj, dict)
+        return StdCellSyntheticProvider(valobj, _dict)
     if rust_type == RustType.STD_REF:
-        return StdRefSyntheticProvider(valobj, dict)
+        return StdRefSyntheticProvider(valobj, _dict)
     if rust_type == RustType.STD_REF_MUT:
-        return StdRefSyntheticProvider(valobj, dict)
+        return StdRefSyntheticProvider(valobj, _dict)
     if rust_type == RustType.STD_REF_CELL:
-        return StdRefSyntheticProvider(valobj, dict, is_cell=True)
+        return StdRefSyntheticProvider(valobj, _dict, is_cell=True)
 
-    return DefaultSyntheticProvider(valobj, dict)
+    return DefaultSyntheticProvider(valobj, _dict)
diff --git a/src/etc/lldb_providers.py b/src/etc/lldb_providers.py
index c24ec8ab31091..2f32ed833af1e 100644
--- a/src/etc/lldb_providers.py
+++ b/src/etc/lldb_providers.py
@@ -3,6 +3,7 @@
 from lldb import (
     SBData,
     SBError,
+    SBValue,
     eBasicTypeLong,
     eBasicTypeUnsignedLong,
     eBasicTypeUnsignedChar,
@@ -44,24 +45,28 @@
 PY3 = sys.version_info[0] == 3
 
 
+class LLDBOpaque:
+    """
+    An marker type for use in type hints to denote LLDB bookkeeping variables. Values marked with
+    this type should never be used except when passing as an argument to an LLDB function.
+    """
+
+
 class ValueBuilder:
-    def __init__(self, valobj):
-        # type: (SBValue) -> ValueBuilder
+    def __init__(self, valobj: SBValue):
         self.valobj = valobj
         process = valobj.GetProcess()
         self.endianness = process.GetByteOrder()
         self.pointer_size = process.GetAddressByteSize()
 
-    def from_int(self, name, value):
-        # type: (str, int) -> SBValue
+    def from_int(self, name: str, value: int) -> SBValue:
         type = self.valobj.GetType().GetBasicType(eBasicTypeLong)
         data = SBData.CreateDataFromSInt64Array(
             self.endianness, self.pointer_size, [value]
         )
         return self.valobj.CreateValueFromData(name, data, type)
 
-    def from_uint(self, name, value):
-        # type: (str, int) -> SBValue
+    def from_uint(self, name: str, value: int) -> SBValue:
         type = self.valobj.GetType().GetBasicType(eBasicTypeUnsignedLong)
         data = SBData.CreateDataFromUInt64Array(
             self.endianness, self.pointer_size, [value]
@@ -69,7 +74,7 @@ def from_uint(self, name, value):
         return self.valobj.CreateValueFromData(name, data, type)
 
 
-def unwrap_unique_or_non_null(unique_or_nonnull):
+def unwrap_unique_or_non_null(unique_or_nonnull: SBValue) -> SBValue:
     # BACKCOMPAT: rust 1.32
     # https://github.com/rust-lang/rust/commit/7a0911528058e87d22ea305695f4047572c5e067
     # BACKCOMPAT: rust 1.60
@@ -79,67 +84,54 @@ def unwrap_unique_or_non_null(unique_or_nonnull):
 
 
 class DefaultSyntheticProvider:
-    def __init__(self, valobj, dict):
-        # type: (SBValue, dict) -> DefaultSyntheticProvider
+    def __init__(self, valobj: SBValue, _dict: LLDBOpaque):
         # logger = Logger.Logger()
         # logger >> "Default synthetic provider for " + str(valobj.GetName())
         self.valobj = valobj
 
-    def num_children(self):
-        # type: () -> int
+    def num_children(self) -> int:
         return self.valobj.GetNumChildren()
 
-    def get_child_index(self, name):
-        # type: (str) -> int
+    def get_child_index(self, name: str) -> int:
         return self.valobj.GetIndexOfChildWithName(name)
 
-    def get_child_at_index(self, index):
-        # type: (int) -> SBValue
+    def get_child_at_index(self, index: int) -> SBValue:
         return self.valobj.GetChildAtIndex(index)
 
     def update(self):
-        # type: () -> None
         pass
 
-    def has_children(self):
-        # type: () -> bool
+    def has_children(self) -> bool:
         return self.valobj.MightHaveChildren()
 
 
 class EmptySyntheticProvider:
-    def __init__(self, valobj, dict):
-        # type: (SBValue, dict) -> EmptySyntheticProvider
+    def __init__(self, valobj: SBValue, _dict: LLDBOpaque):
         # logger = Logger.Logger()
         # logger >> "[EmptySyntheticProvider] for " + str(valobj.GetName())
         self.valobj = valobj
 
-    def num_children(self):
-        # type: () -> int
+    def num_children(self) -> int:
         return 0
 
-    def get_child_index(self, name):
-        # type: (str) -> int
-        return None
+    def get_child_index(self, name: str) -> int:
+        return -1
 
-    def get_child_at_index(self, index):
-        # type: (int) -> SBValue
+    def get_child_at_index(self, index: int) -> SBValue:
         return None
 
     def update(self):
-        # type: () -> None
         pass
 
-    def has_children(self):
-        # type: () -> bool
+    def has_children(self) -> bool:
         return False
 
 
-def SizeSummaryProvider(valobj, dict):
-    # type: (SBValue, dict) -> str
+def SizeSummaryProvider(valobj: SBValue, _dict: LLDBOpaque) -> str:
     return "size=" + str(valobj.GetNumChildren())
 
 
-def vec_to_string(vec):
+def vec_to_string(vec: SBValue) -> str:
     length = vec.GetNumChildren()
     chars = [vec.GetChildAtIndex(i).GetValueAsUnsigned() for i in range(length)]
     return (
@@ -149,16 +141,14 @@ def vec_to_string(vec):
     )
 
 
-def StdStringSummaryProvider(valobj, dict):
-    # type: (SBValue, dict) -> str
+def StdStringSummaryProvider(valobj: SBValue, _dict: LLDBOpaque) -> str:
     # logger = Logger.Logger()
     # logger >> "[StdStringSummaryProvider] for " + str(valobj.GetName())
     vec = valobj.GetChildAtIndex(0)
     return '"%s"' % vec_to_string(vec)
 
 
-def StdOsStringSummaryProvider(valobj, dict):
-    # type: (SBValue, dict) -> str
+def StdOsStringSummaryProvider(valobj: SBValue, _dict: LLDBOpaque) -> str:
     # logger = Logger.Logger()
     # logger >> "[StdOsStringSummaryProvider] for " + str(valobj.GetName())
     buf = valobj.GetChildAtIndex(0).GetChildAtIndex(0)
@@ -167,8 +157,7 @@ def StdOsStringSummaryProvider(valobj, dict):
     return '"%s"' % vec_to_string(vec)
 
 
-def StdStrSummaryProvider(valobj, dict):
-    # type: (SBValue, dict) -> str
+def StdStrSummaryProvider(valobj: SBValue, _dict: LLDBOpaque) -> str:
     # logger = Logger.Logger()
     # logger >> "[StdStrSummaryProvider] for " + str(valobj.GetName())
 
@@ -189,15 +178,13 @@ def StdStrSummaryProvider(valobj, dict):
     return '"%s"' % data
 
 
-def StdPathBufSummaryProvider(valobj, dict):
-    # type: (SBValue, dict) -> str
+def StdPathBufSummaryProvider(valobj: SBValue, _dict: LLDBOpaque) -> str:
     # logger = Logger.Logger()
     # logger >> "[StdPathBufSummaryProvider] for " + str(valobj.GetName())
-    return StdOsStringSummaryProvider(valobj.GetChildMemberWithName("inner"), dict)
+    return StdOsStringSummaryProvider(valobj.GetChildMemberWithName("inner"), _dict)
 
 
-def StdPathSummaryProvider(valobj, dict):
-    # type: (SBValue, dict) -> str
+def StdPathSummaryProvider(valobj: SBValue, _dict: LLDBOpaque) -> str:
     # logger = Logger.Logger()
     # logger >> "[StdPathSummaryProvider] for " + str(valobj.GetName())
     length = valobj.GetChildMemberWithName("length").GetValueAsUnsigned()
@@ -221,8 +208,7 @@ def StdPathSummaryProvider(valobj, dict):
 class StructSyntheticProvider:
     """Pretty-printer for structs and struct enum variants"""
 
-    def __init__(self, valobj, dict, is_variant=False):
-        # type: (SBValue, dict, bool) -> StructSyntheticProvider
+    def __init__(self, valobj: SBValue, _dict: LLDBOpaque, is_variant: bool = False):
         # logger = Logger.Logger()
         self.valobj = valobj
         self.is_variant = is_variant
@@ -239,16 +225,13 @@ def __init__(self, valobj, dict, is_variant=False):
         for number, field in enumerate(real_fields):
             self.fields[field.name] = number
 
-    def num_children(self):
-        # type: () -> int
+    def num_children(self) -> int:
         return self.fields_count
 
-    def get_child_index(self, name):
-        # type: (str) -> int
+    def get_child_index(self, name: str) -> int:
         return self.fields.get(name, -1)
 
-    def get_child_at_index(self, index):
-        # type: (int) -> SBValue
+    def get_child_at_index(self, index: int) -> SBValue:
         if self.is_variant:
             field = self.type.GetFieldAtIndex(index + 1)
         else:
@@ -259,8 +242,7 @@ def update(self):
         # type: () -> None
         pass
 
-    def has_children(self):
-        # type: () -> bool
+    def has_children(self) -> bool:
         return True
 
 
@@ -270,26 +252,26 @@ class ClangEncodedEnumProvider:
     DISCRIMINANT_MEMBER_NAME = "$discr$"
     VALUE_MEMBER_NAME = "value"
 
-    def __init__(self, valobj, dict):
+    def __init__(self, valobj: SBValue, _dict: LLDBOpaque):
         self.valobj = valobj
         self.update()
 
-    def has_children(self):
+    def has_children(self) -> bool:
         return True
 
-    def num_children(self):
+    def num_children(self) -> int:
         if self.is_default:
             return 1
         return 2
 
-    def get_child_index(self, name):
+    def get_child_index(self, name: str) -> int:
         if name == ClangEncodedEnumProvider.VALUE_MEMBER_NAME:
             return 0
         if name == ClangEncodedEnumProvider.DISCRIMINANT_MEMBER_NAME:
             return 1
         return -1
 
-    def get_child_at_index(self, index):
+    def get_child_at_index(self, index: int) -> SBValue:
         if index == 0:
             return self.variant.GetChildMemberWithName(
                 ClangEncodedEnumProvider.VALUE_MEMBER_NAME
@@ -310,7 +292,7 @@ def update(self):
             == -1
         )
 
-    def _getCurrentVariantIndex(self, all_variants):
+    def _getCurrentVariantIndex(self, all_variants: SBValue) -> int:
         default_index = 0
         for i in range(all_variants.GetNumChildren()):
             variant = all_variants.GetChildAtIndex(i)
@@ -329,8 +311,7 @@ def _getCurrentVariantIndex(self, all_variants):
 class TupleSyntheticProvider:
     """Pretty-printer for tuples and tuple enum variants"""
 
-    def __init__(self, valobj, dict, is_variant=False):
-        # type: (SBValue, dict, bool) -> TupleSyntheticProvider
+    def __init__(self, valobj: SBValue, _dict: LLDBOpaque, is_variant: bool = False):
         # logger = Logger.Logger()
         self.valobj = valobj
         self.is_variant = is_variant
@@ -341,19 +322,16 @@ def __init__(self, valobj, dict, is_variant=False):
         else:
             self.size = self.type.GetNumberOfFields()
 
-    def num_children(self):
-        # type: () -> int
+    def num_children(self) -> int:
         return self.size
 
-    def get_child_index(self, name):
-        # type: (str) -> int
+    def get_child_index(self, name: str) -> int:
         if name.isdigit():
             return int(name)
         else:
             return -1
 
-    def get_child_at_index(self, index):
-        # type: (int) -> SBValue
+    def get_child_at_index(self, index: int) -> SBValue:
         if self.is_variant:
             field = self.type.GetFieldAtIndex(index + 1)
         else:
@@ -364,11 +342,9 @@ def get_child_at_index(self, index):
         )
 
     def update(self):
-        # type: () -> None
         pass
 
-    def has_children(self):
-        # type: () -> bool
+    def has_children(self) -> bool:
         return True
 
 
@@ -385,27 +361,23 @@ class StdVecSyntheticProvider:
     struct NonNull<T> { pointer: *const T }
     """
 
-    def __init__(self, valobj, dict):
-        # type: (SBValue, dict) -> StdVecSyntheticProvider
+    def __init__(self, valobj: SBValue, _dict: LLDBOpaque):
         # logger = Logger.Logger()
         # logger >> "[StdVecSyntheticProvider] for " + str(valobj.GetName())
         self.valobj = valobj
         self.update()
 
-    def num_children(self):
-        # type: () -> int
+    def num_children(self) -> int:
         return self.length
 
-    def get_child_index(self, name):
-        # type: (str) -> int
+    def get_child_index(self, name: str) -> int:
         index = name.lstrip("[").rstrip("]")
         if index.isdigit():
             return int(index)
         else:
             return -1
 
-    def get_child_at_index(self, index):
-        # type: (int) -> SBValue
+    def get_child_at_index(self, index: int) -> SBValue:
         start = self.data_ptr.GetValueAsUnsigned()
         address = start + index * self.element_type_size
         element = self.data_ptr.CreateValueFromAddress(
@@ -414,7 +386,6 @@ def get_child_at_index(self, index):
         return element
 
     def update(self):
-        # type: () -> None
         self.length = self.valobj.GetChildMemberWithName("len").GetValueAsUnsigned()
         self.buf = self.valobj.GetChildMemberWithName("buf").GetChildMemberWithName(
             "inner"
@@ -427,30 +398,26 @@ def update(self):
         self.element_type = self.valobj.GetType().GetTemplateArgumentType(0)
         self.element_type_size = self.element_type.GetByteSize()
 
-    def has_children(self):
-        # type: () -> bool
+    def has_children(self) -> bool:
         return True
 
 
 class StdSliceSyntheticProvider:
-    def __init__(self, valobj, dict):
+    def __init__(self, valobj: SBValue, _dict: LLDBOpaque):
         self.valobj = valobj
         self.update()
 
-    def num_children(self):
-        # type: () -> int
+    def num_children(self) -> int:
         return self.length
 
-    def get_child_index(self, name):
-        # type: (str) -> int
+    def get_child_index(self, name: str) -> int:
         index = name.lstrip("[").rstrip("]")
         if index.isdigit():
             return int(index)
         else:
             return -1
 
-    def get_child_at_index(self, index):
-        # type: (int) -> SBValue
+    def get_child_at_index(self, index: int) -> SBValue:
         start = self.data_ptr.GetValueAsUnsigned()
         address = start + index * self.element_type_size
         element = self.data_ptr.CreateValueFromAddress(
@@ -459,15 +426,13 @@ def get_child_at_index(self, index):
         return element
 
     def update(self):
-        # type: () -> None
         self.length = self.valobj.GetChildMemberWithName("length").GetValueAsUnsigned()
         self.data_ptr = self.valobj.GetChildMemberWithName("data_ptr")
 
         self.element_type = self.data_ptr.GetType().GetPointeeType()
         self.element_type_size = self.element_type.GetByteSize()
 
-    def has_children(self):
-        # type: () -> bool
+    def has_children(self) -> bool:
         return True
 
 
@@ -477,27 +442,23 @@ class StdVecDequeSyntheticProvider:
     struct VecDeque<T> { head: usize, len: usize, buf: RawVec<T> }
     """
 
-    def __init__(self, valobj, dict):
-        # type: (SBValue, dict) -> StdVecDequeSyntheticProvider
+    def __init__(self, valobj: SBValue, _dict: LLDBOpaque):
         # logger = Logger.Logger()
         # logger >> "[StdVecDequeSyntheticProvider] for " + str(valobj.GetName())
         self.valobj = valobj
         self.update()
 
-    def num_children(self):
-        # type: () -> int
+    def num_children(self) -> int:
         return self.size
 
-    def get_child_index(self, name):
-        # type: (str) -> int
+    def get_child_index(self, name: str) -> int:
         index = name.lstrip("[").rstrip("]")
         if index.isdigit() and int(index) < self.size:
             return int(index)
         else:
             return -1
 
-    def get_child_at_index(self, index):
-        # type: (int) -> SBValue
+    def get_child_at_index(self, index: int) -> SBValue:
         start = self.data_ptr.GetValueAsUnsigned()
         address = start + ((index + self.head) % self.cap) * self.element_type_size
         element = self.data_ptr.CreateValueFromAddress(
@@ -506,7 +467,6 @@ def get_child_at_index(self, index):
         return element
 
     def update(self):
-        # type: () -> None
         self.head = self.valobj.GetChildMemberWithName("head").GetValueAsUnsigned()
         self.size = self.valobj.GetChildMemberWithName("len").GetValueAsUnsigned()
         self.buf = self.valobj.GetChildMemberWithName("buf").GetChildMemberWithName(
@@ -524,8 +484,7 @@ def update(self):
         self.element_type = self.valobj.GetType().GetTemplateArgumentType(0)
         self.element_type_size = self.element_type.GetByteSize()
 
-    def has_children(self):
-        # type: () -> bool
+    def has_children(self) -> bool:
         return True
 
 
@@ -537,26 +496,22 @@ class StdOldHashMapSyntheticProvider:
     struct RawTable<K, V> { capacity_mask: usize, size: usize, hashes: TaggedHashUintPtr, ... }
     """
 
-    def __init__(self, valobj, dict, show_values=True):
-        # type: (SBValue, dict, bool) -> StdOldHashMapSyntheticProvider
+    def __init__(self, valobj: SBValue, _dict: LLDBOpaque, show_values: bool = True):
         self.valobj = valobj
         self.show_values = show_values
         self.update()
 
-    def num_children(self):
-        # type: () -> int
+    def num_children(self) -> int:
         return self.size
 
-    def get_child_index(self, name):
-        # type: (str) -> int
+    def get_child_index(self, name: str) -> int:
         index = name.lstrip("[").rstrip("]")
         if index.isdigit():
             return int(index)
         else:
             return -1
 
-    def get_child_at_index(self, index):
-        # type: (int) -> SBValue
+    def get_child_at_index(self, index: int) -> SBValue:
         # logger = Logger.Logger()
         start = self.data_ptr.GetValueAsUnsigned() & ~1
 
@@ -592,7 +547,6 @@ def get_child_at_index(self, index):
             )
 
     def update(self):
-        # type: () -> None
         # logger = Logger.Logger()
 
         self.table = self.valobj.GetChildMemberWithName("table")  # type: SBValue
@@ -624,34 +578,29 @@ def update(self):
 
         # logger >> "Valid indices: {}".format(str(self.valid_indices))
 
-    def has_children(self):
-        # type: () -> bool
+    def has_children(self) -> bool:
         return True
 
 
 class StdHashMapSyntheticProvider:
     """Pretty-printer for hashbrown's HashMap"""
 
-    def __init__(self, valobj, dict, show_values=True):
-        # type: (SBValue, dict, bool) -> StdHashMapSyntheticProvider
+    def __init__(self, valobj: SBValue, _dict: LLDBOpaque, show_values: bool = True):
         self.valobj = valobj
         self.show_values = show_values
         self.update()
 
-    def num_children(self):
-        # type: () -> int
+    def num_children(self) -> int:
         return self.size
 
-    def get_child_index(self, name):
-        # type: (str) -> int
+    def get_child_index(self, name: str) -> int:
         index = name.lstrip("[").rstrip("]")
         if index.isdigit():
             return int(index)
         else:
             return -1
 
-    def get_child_at_index(self, index):
-        # type: (int) -> SBValue
+    def get_child_at_index(self, index: int) -> SBValue:
         pairs_start = self.data_ptr.GetValueAsUnsigned()
         idx = self.valid_indices[index]
         if self.new_layout:
@@ -669,7 +618,6 @@ def get_child_at_index(self, index):
             )
 
     def update(self):
-        # type: () -> None
         table = self.table()
         inner_table = table.GetChildMemberWithName("table")
 
@@ -707,8 +655,7 @@ def update(self):
             if is_present:
                 self.valid_indices.append(idx)
 
-    def table(self):
-        # type: () -> SBValue
+    def table(self) -> SBValue:
         if self.show_values:
             hashbrown_hashmap = self.valobj.GetChildMemberWithName("base")
         else:
@@ -718,13 +665,11 @@ def table(self):
             hashbrown_hashmap = self.valobj.GetChildAtIndex(0).GetChildAtIndex(0)
         return hashbrown_hashmap.GetChildMemberWithName("table")
 
-    def has_children(self):
-        # type: () -> bool
+    def has_children(self) -> bool:
         return True
 
 
-def StdRcSummaryProvider(valobj, dict):
-    # type: (SBValue, dict) -> str
+def StdRcSummaryProvider(valobj: SBValue, _dict: LLDBOpaque) -> str:
     strong = valobj.GetChildMemberWithName("strong").GetValueAsUnsigned()
     weak = valobj.GetChildMemberWithName("weak").GetValueAsUnsigned()
     return "strong={}, weak={}".format(strong, weak)
@@ -746,8 +691,7 @@ class StdRcSyntheticProvider:
     struct AtomicUsize { v: UnsafeCell<usize> }
     """
 
-    def __init__(self, valobj, dict, is_atomic=False):
-        # type: (SBValue, dict, bool) -> StdRcSyntheticProvider
+    def __init__(self, valobj: SBValue, _dict: LLDBOpaque, is_atomic: bool = False):
         self.valobj = valobj
 
         self.ptr = unwrap_unique_or_non_null(self.valobj.GetChildMemberWithName("ptr"))
@@ -769,13 +713,11 @@ def __init__(self, valobj, dict, is_atomic=False):
 
         self.update()
 
-    def num_children(self):
-        # type: () -> int
+    def num_children(self) -> int:
         # Actually there are 3 children, but only the `value` should be shown as a child
         return 1
 
-    def get_child_index(self, name):
-        # type: (str) -> int
+    def get_child_index(self, name: str) -> int:
         if name == "value":
             return 0
         if name == "strong":
@@ -784,8 +726,7 @@ def get_child_index(self, name):
             return 2
         return -1
 
-    def get_child_at_index(self, index):
-        # type: (int) -> SBValue
+    def get_child_at_index(self, index: int) -> SBValue:
         if index == 0:
             return self.value
         if index == 1:
@@ -796,50 +737,41 @@ def get_child_at_index(self, index):
         return None
 
     def update(self):
-        # type: () -> None
         self.strong_count = self.strong.GetValueAsUnsigned()
         self.weak_count = self.weak.GetValueAsUnsigned() - 1
 
-    def has_children(self):
-        # type: () -> bool
+    def has_children(self) -> bool:
         return True
 
 
 class StdCellSyntheticProvider:
     """Pretty-printer for std::cell::Cell"""
 
-    def __init__(self, valobj, dict):
-        # type: (SBValue, dict) -> StdCellSyntheticProvider
+    def __init__(self, valobj: SBValue, _dict: LLDBOpaque):
         self.valobj = valobj
         self.value = valobj.GetChildMemberWithName("value").GetChildAtIndex(0)
 
-    def num_children(self):
-        # type: () -> int
+    def num_children(self) -> int:
         return 1
 
-    def get_child_index(self, name):
-        # type: (str) -> int
+    def get_child_index(self, name: str) -> int:
         if name == "value":
             return 0
         return -1
 
-    def get_child_at_index(self, index):
-        # type: (int) -> SBValue
+    def get_child_at_index(self, index: int) -> SBValue:
         if index == 0:
             return self.value
         return None
 
     def update(self):
-        # type: () -> None
         pass
 
-    def has_children(self):
-        # type: () -> bool
+    def has_children(self) -> bool:
         return True
 
 
-def StdRefSummaryProvider(valobj, dict):
-    # type: (SBValue, dict) -> str
+def StdRefSummaryProvider(valobj: SBValue, _dict: LLDBOpaque) -> str:
     borrow = valobj.GetChildMemberWithName("borrow").GetValueAsSigned()
     return (
         "borrow={}".format(borrow) if borrow >= 0 else "borrow_mut={}".format(-borrow)
@@ -849,8 +781,7 @@ def StdRefSummaryProvider(valobj, dict):
 class StdRefSyntheticProvider:
     """Pretty-printer for std::cell::Ref, std::cell::RefMut, and std::cell::RefCell"""
 
-    def __init__(self, valobj, dict, is_cell=False):
-        # type: (SBValue, dict, bool) -> StdRefSyntheticProvider
+    def __init__(self, valobj: SBValue, _dict: LLDBOpaque, is_cell: bool = False):
         self.valobj = valobj
 
         borrow = valobj.GetChildMemberWithName("borrow")
@@ -872,20 +803,18 @@ def __init__(self, valobj, dict, is_cell=False):
 
         self.update()
 
-    def num_children(self):
-        # type: () -> int
+    def num_children(self) -> int:
         # Actually there are 2 children, but only the `value` should be shown as a child
         return 1
 
-    def get_child_index(self, name):
+    def get_child_index(self, name: str) -> int:
         if name == "value":
             return 0
         if name == "borrow":
             return 1
         return -1
 
-    def get_child_at_index(self, index):
-        # type: (int) -> SBValue
+    def get_child_at_index(self, index: int) -> SBValue:
         if index == 0:
             return self.value
         if index == 1:
@@ -893,16 +822,13 @@ def get_child_at_index(self, index):
         return None
 
     def update(self):
-        # type: () -> None
         self.borrow_count = self.borrow.GetValueAsSigned()
 
-    def has_children(self):
-        # type: () -> bool
+    def has_children(self) -> bool:
         return True
 
 
-def StdNonZeroNumberSummaryProvider(valobj, _dict):
-    # type: (SBValue, dict) -> str
+def StdNonZeroNumberSummaryProvider(valobj: SBValue, _dict: LLDBOpaque) -> str:
     inner = valobj.GetChildAtIndex(0)
     inner_inner = inner.GetChildAtIndex(0)
 
diff --git a/src/etc/rust_types.py b/src/etc/rust_types.py
index 42ec9bed9bdc3..af03e8ede9c3f 100644
--- a/src/etc/rust_types.py
+++ b/src/etc/rust_types.py
@@ -1,3 +1,4 @@
+from typing import List
 import re
 
 
@@ -85,12 +86,11 @@ class RustType(object):
 }
 
 
-def is_tuple_fields(fields):
-    # type: (list) -> bool
+def is_tuple_fields(fields: List) -> bool:
     return all(TUPLE_ITEM_REGEX.match(str(field.name)) for field in fields)
 
 
-def classify_struct(name, fields):
+def classify_struct(name: str, fields: List) -> str:
     if len(fields) == 0:
         return RustType.EMPTY
 
@@ -111,7 +111,7 @@ def classify_struct(name, fields):
     return RustType.STRUCT
 
 
-def classify_union(fields):
+def classify_union(fields: List) -> str:
     if len(fields) == 0:
         return RustType.EMPTY
 
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 3c9e0914b59d7..0f84b43866290 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -1844,8 +1844,8 @@ pub(crate) fn clean_ty<'tcx>(ty: &hir::Ty<'tcx>, cx: &mut DocContext<'tcx>) -> T
             DynTrait(bounds, lifetime)
         }
         TyKind::BareFn(barefn) => BareFunction(Box::new(clean_bare_fn_ty(barefn, cx))),
-        TyKind::UnsafeBinder(..) => {
-            unimplemented!("unsafe binders are not supported yet")
+        TyKind::UnsafeBinder(unsafe_binder_ty) => {
+            UnsafeBinder(Box::new(clean_unsafe_binder_ty(unsafe_binder_ty, cx)))
         }
         // Rustdoc handles `TyKind::Err`s by turning them into `Type::Infer`s.
         TyKind::Infer
@@ -2075,6 +2075,11 @@ pub(crate) fn clean_middle_ty<'tcx>(
                 abi: sig.abi(),
             }))
         }
+        ty::UnsafeBinder(inner) => {
+            let generic_params = clean_bound_vars(inner.bound_vars());
+            let ty = clean_middle_ty(inner.into(), cx, None, None);
+            UnsafeBinder(Box::new(UnsafeBinderTy { generic_params, ty }))
+        }
         ty::Adt(def, args) => {
             let did = def.did();
             let kind = match def.adt_kind() {
@@ -2253,7 +2258,6 @@ pub(crate) fn clean_middle_ty<'tcx>(
             }
         }
 
-        ty::UnsafeBinder(_) => todo!("FIXME(unsafe_binders)"),
         ty::Closure(..) => panic!("Closure"),
         ty::CoroutineClosure(..) => panic!("CoroutineClosure"),
         ty::Coroutine(..) => panic!("Coroutine"),
@@ -2564,6 +2568,21 @@ fn clean_bare_fn_ty<'tcx>(
     BareFunctionDecl { safety: bare_fn.safety, abi: bare_fn.abi, decl, generic_params }
 }
 
+fn clean_unsafe_binder_ty<'tcx>(
+    unsafe_binder_ty: &hir::UnsafeBinderTy<'tcx>,
+    cx: &mut DocContext<'tcx>,
+) -> UnsafeBinderTy {
+    // NOTE: generics must be cleaned before args
+    let generic_params = unsafe_binder_ty
+        .generic_params
+        .iter()
+        .filter(|p| !is_elided_lifetime(p))
+        .map(|x| clean_generic_param(cx, None, x))
+        .collect();
+    let ty = clean_ty(unsafe_binder_ty.inner_ty, cx);
+    UnsafeBinderTy { generic_params, ty }
+}
+
 pub(crate) fn reexport_chain(
     tcx: TyCtxt<'_>,
     import_def_id: LocalDefId,
diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
index 8c7ab925577df..3c4fad4bca97e 100644
--- a/src/librustdoc/clean/types.rs
+++ b/src/librustdoc/clean/types.rs
@@ -32,7 +32,7 @@ use {rustc_ast as ast, rustc_hir as hir};
 pub(crate) use self::ItemKind::*;
 pub(crate) use self::Type::{
     Array, BareFunction, BorrowedRef, DynTrait, Generic, ImplTrait, Infer, Primitive, QPath,
-    RawPointer, SelfTy, Slice, Tuple,
+    RawPointer, SelfTy, Slice, Tuple, UnsafeBinder,
 };
 use crate::clean::cfg::Cfg;
 use crate::clean::clean_middle_path;
@@ -1511,6 +1511,8 @@ pub(crate) enum Type {
 
     /// An `impl Trait`: `impl TraitA + TraitB + ...`
     ImplTrait(Vec<GenericBound>),
+
+    UnsafeBinder(Box<UnsafeBinderTy>),
 }
 
 impl Type {
@@ -1703,7 +1705,7 @@ impl Type {
             Type::Pat(..) => PrimitiveType::Pat,
             RawPointer(..) => PrimitiveType::RawPointer,
             QPath(box QPathData { ref self_type, .. }) => return self_type.def_id(cache),
-            Generic(_) | SelfTy | Infer | ImplTrait(_) => return None,
+            Generic(_) | SelfTy | Infer | ImplTrait(_) | UnsafeBinder(_) => return None,
         };
         Primitive(t).def_id(cache)
     }
@@ -2343,6 +2345,12 @@ pub(crate) struct BareFunctionDecl {
     pub(crate) abi: ExternAbi,
 }
 
+#[derive(Clone, PartialEq, Eq, Debug, Hash)]
+pub(crate) struct UnsafeBinderTy {
+    pub(crate) generic_params: Vec<GenericParamDef>,
+    pub(crate) ty: Type,
+}
+
 #[derive(Clone, Debug)]
 pub(crate) struct Static {
     pub(crate) type_: Box<Type>,
diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index 136002b8e155b..621abd535010f 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -282,7 +282,8 @@ pub(crate) fn print_where_clause<'a, 'tcx: 'a>(
 
                     match pred {
                         clean::WherePredicate::BoundPredicate { ty, bounds, bound_params } => {
-                            print_higher_ranked_params_with_space(bound_params, cx).fmt(f)?;
+                            print_higher_ranked_params_with_space(bound_params, cx, "for")
+                                .fmt(f)?;
                             ty.print(cx).fmt(f)?;
                             f.write_str(":")?;
                             if !bounds.is_empty() {
@@ -386,7 +387,7 @@ impl clean::ConstantKind {
 impl clean::PolyTrait {
     fn print<'a, 'tcx: 'a>(&'a self, cx: &'a Context<'tcx>) -> impl Display + 'a + Captures<'tcx> {
         display_fn(move |f| {
-            print_higher_ranked_params_with_space(&self.generic_params, cx).fmt(f)?;
+            print_higher_ranked_params_with_space(&self.generic_params, cx, "for").fmt(f)?;
             self.trait_.print(cx).fmt(f)
         })
     }
@@ -968,10 +969,12 @@ fn tybounds<'a, 'tcx: 'a>(
 fn print_higher_ranked_params_with_space<'a, 'tcx: 'a>(
     params: &'a [clean::GenericParamDef],
     cx: &'a Context<'tcx>,
+    keyword: &'static str,
 ) -> impl Display + 'a + Captures<'tcx> {
     display_fn(move |f| {
         if !params.is_empty() {
-            f.write_str(if f.alternate() { "for<" } else { "for&lt;" })?;
+            f.write_str(keyword)?;
+            f.write_str(if f.alternate() { "<" } else { "&lt;" })?;
             comma_sep(params.iter().map(|lt| lt.print(cx)), true).fmt(f)?;
             f.write_str(if f.alternate() { "> " } else { "&gt; " })?;
         }
@@ -1027,7 +1030,7 @@ fn fmt_type(
             primitive_link(f, prim, format_args!("{}", prim.as_sym().as_str()), cx)
         }
         clean::BareFunction(ref decl) => {
-            print_higher_ranked_params_with_space(&decl.generic_params, cx).fmt(f)?;
+            print_higher_ranked_params_with_space(&decl.generic_params, cx, "for").fmt(f)?;
             decl.safety.print_with_space().fmt(f)?;
             print_abi_with_space(decl.abi).fmt(f)?;
             if f.alternate() {
@@ -1037,6 +1040,10 @@ fn fmt_type(
             }
             decl.decl.print(cx).fmt(f)
         }
+        clean::UnsafeBinder(ref binder) => {
+            print_higher_ranked_params_with_space(&binder.generic_params, cx, "unsafe").fmt(f)?;
+            binder.ty.print(cx).fmt(f)
+        }
         clean::Tuple(ref typs) => match &typs[..] {
             &[] => primitive_link(f, PrimitiveType::Unit, format_args!("()"), cx),
             [one] => {
@@ -1354,7 +1361,7 @@ impl clean::Impl {
             // Hardcoded anchor library/core/src/primitive_docs.rs
             // Link should match `# Trait implementations`
 
-            print_higher_ranked_params_with_space(&bare_fn.generic_params, cx).fmt(f)?;
+            print_higher_ranked_params_with_space(&bare_fn.generic_params, cx, "for").fmt(f)?;
             bare_fn.safety.print_with_space().fmt(f)?;
             print_abi_with_space(bare_fn.abi).fmt(f)?;
             let ellipsis = if bare_fn.decl.c_variadic { ", ..." } else { "" };
diff --git a/src/librustdoc/html/render/search_index.rs b/src/librustdoc/html/render/search_index.rs
index fe2e155c9ba7a..66c52bec4bad7 100644
--- a/src/librustdoc/html/render/search_index.rs
+++ b/src/librustdoc/html/render/search_index.rs
@@ -900,7 +900,8 @@ fn get_index_type_id(
         | clean::Generic(_)
         | clean::SelfTy
         | clean::ImplTrait(_)
-        | clean::Infer => None,
+        | clean::Infer
+        | clean::UnsafeBinder(_) => None,
     }
 }
 
diff --git a/src/librustdoc/json/conversions.rs b/src/librustdoc/json/conversions.rs
index 7f072aa7e2fc4..7fcdfe3fb22ea 100644
--- a/src/librustdoc/json/conversions.rs
+++ b/src/librustdoc/json/conversions.rs
@@ -573,7 +573,7 @@ impl FromClean<clean::Type> for Type {
     fn from_clean(ty: clean::Type, renderer: &JsonRenderer<'_>) -> Self {
         use clean::Type::{
             Array, BareFunction, BorrowedRef, Generic, ImplTrait, Infer, Primitive, QPath,
-            RawPointer, SelfTy, Slice, Tuple,
+            RawPointer, SelfTy, Slice, Tuple, UnsafeBinder,
         };
 
         match ty {
@@ -613,6 +613,8 @@ impl FromClean<clean::Type> for Type {
                 self_type: Box::new(self_type.into_json(renderer)),
                 trait_: trait_.map(|trait_| trait_.into_json(renderer)),
             },
+            // FIXME(unsafe_binder): Implement rustdoc-json.
+            UnsafeBinder(_) => todo!(),
         }
     }
 }
diff --git a/tests/rustdoc-ui/doctest/non-local-defs-impl.rs b/tests/rustdoc-ui/doctest/non-local-defs-impl.rs
index 04fdd2855067d..f2540574f15ae 100644
--- a/tests/rustdoc-ui/doctest/non-local-defs-impl.rs
+++ b/tests/rustdoc-ui/doctest/non-local-defs-impl.rs
@@ -21,7 +21,7 @@
 /// }
 /// ```
 ///
-/// But this shoudln't produce a warning:
+/// But this shouldn't produce a warning:
 /// ```rust,no_run
 /// # extern crate pub_trait;
 /// # use pub_trait::Trait;
diff --git a/tests/rustdoc/auxiliary/unsafe-binder-dep.rs b/tests/rustdoc/auxiliary/unsafe-binder-dep.rs
new file mode 100644
index 0000000000000..65aa9032fed19
--- /dev/null
+++ b/tests/rustdoc/auxiliary/unsafe-binder-dep.rs
@@ -0,0 +1,4 @@
+#![feature(unsafe_binders)]
+#![allow(incomplete_features)]
+
+pub fn woof() -> unsafe<'a> &'a str { todo!() }
diff --git a/tests/rustdoc/unsafe-binder.rs b/tests/rustdoc/unsafe-binder.rs
new file mode 100644
index 0000000000000..621c3dadc72ee
--- /dev/null
+++ b/tests/rustdoc/unsafe-binder.rs
@@ -0,0 +1,15 @@
+//@ aux-build:unsafe-binder-dep.rs
+
+#![feature(unsafe_binders)]
+#![allow(incomplete_features)]
+
+extern crate unsafe_binder_dep;
+
+//@ has 'unsafe_binder/fn.woof.html' //pre "fn woof() -> unsafe<'a> &'a str"
+pub use unsafe_binder_dep::woof;
+
+//@ has 'unsafe_binder/fn.meow.html' //pre "fn meow() -> unsafe<'a> &'a str"
+pub fn meow() -> unsafe<'a> &'a str { todo!() }
+
+//@ has 'unsafe_binder/fn.meow_squared.html' //pre "fn meow_squared() -> unsafe<'b, 'a> &'a &'b str"
+pub fn meow_squared() -> unsafe<'b, 'a> &'a &'b str { todo!() }
diff --git a/tests/ui/closures/2229_closure_analysis/issue-118144.rs b/tests/ui/closures/2229_closure_analysis/issue-118144.rs
index 3e5d9f9739a59..5747cc75e98af 100644
--- a/tests/ui/closures/2229_closure_analysis/issue-118144.rs
+++ b/tests/ui/closures/2229_closure_analysis/issue-118144.rs
@@ -6,7 +6,7 @@ fn func(func_arg: &mut V) {
     || {
         // Declaring `x` separately instead of using
         // a destructuring binding like `let V(x) = ...`
-        // becaue only `V(x) = ...` triggers the ICE
+        // because only `V(x) = ...` triggers the ICE
         let x;
         V(x) = func_arg; //~ ERROR: mismatched types
         func_arg.0 = 0;
diff --git a/tests/ui/coroutine/issue-53548.rs b/tests/ui/coroutine/issue-53548.rs
index 3b8dff2be28c1..c70f3e5a0d0a1 100644
--- a/tests/ui/coroutine/issue-53548.rs
+++ b/tests/ui/coroutine/issue-53548.rs
@@ -6,7 +6,7 @@
 // to process this `'r` region bound. In particular, to be WF, the
 // region bound must meet the requirements of the trait, and hence we
 // got `for<'r> { 'r: 'static }`. This would ICE because the `Binder`
-// constructor we were using was assering that no higher-ranked
+// constructor we were using was asserting that no higher-ranked
 // regions were involved (because the WF code is supposed to skip
 // those). The error (if debug-asserions were disabled) came because
 // we obviously cannot prove that `'r: 'static` for any region `'r`.
diff --git a/tests/ui/panics/default-backtrace-ice.rs b/tests/ui/panics/default-backtrace-ice.rs
index c47f458f6e97a..9933f54875836 100644
--- a/tests/ui/panics/default-backtrace-ice.rs
+++ b/tests/ui/panics/default-backtrace-ice.rs
@@ -17,7 +17,7 @@
 // `__rust_{begin,end}_short_backtrace` markers, which only appear in full
 // backtraces. The rest of the backtrace is filtered out.
 //
-// Ignored on msvc becaue the `__rust_{begin,end}_short_backtrace` symbols
+// Ignored on msvc because the `__rust_{begin,end}_short_backtrace` symbols
 // aren't reliable.
 
 fn main() { missing_ident; }