inference: clean up getfield_tfunc subroutines [NFC]

Author: aviatesk

base/compiler/tfuncs.jl

@@ -881,8 +881,7 @@ end
 getfield_tfunc(@nospecialize(s00), @nospecialize(name)) = _getfield_tfunc(fallback_lattice, s00, name, false)
 getfield_tfunc(@specialize(lattice::AbstractLattice), @nospecialize(s00), @nospecialize(name)) = _getfield_tfunc(lattice, s00, name, false)
 
-
-function _getfield_fieldindex(@nospecialize(s), name::Const)
+function _getfield_fieldindex(s::DataType, name::Const)
     nv = name.val
     if isa(nv, Symbol)
         nv = fieldindex(s, nv, false)
@@ -893,19 +892,17 @@ function _getfield_fieldindex(@nospecialize(s), name::Const)
     return nothing
 end
 
-function _getfield_tfunc_const(@nospecialize(sv), name::Const, setfield::Bool)
-    if isa(name, Const)
-        nv = _getfield_fieldindex(typeof(sv), name)
-        nv === nothing && return Bottom
-        if isa(sv, DataType) && nv == DATATYPE_TYPES_FIELDINDEX && isdefined(sv, nv)
+function _getfield_tfunc_const(@nospecialize(sv), name::Const)
+    nv = _getfield_fieldindex(typeof(sv), name)
+    nv === nothing && return Bottom
+    if isa(sv, DataType) && nv == DATATYPE_TYPES_FIELDINDEX && isdefined(sv, nv)
+        return Const(getfield(sv, nv))
+    end
+    if isconst(typeof(sv), nv)
+        if isdefined(sv, nv)
             return Const(getfield(sv, nv))
         end
-        if isconst(typeof(sv), nv)
-            if isdefined(sv, nv)
-                return Const(getfield(sv, nv))
-            end
-            return Union{}
-        end
+        return Bottom
     end
     return nothing
 end
@@ -960,7 +957,7 @@ function _getfield_tfunc(lattice::ConstsLattice, @nospecialize(s00), @nospeciali
                 end
                 return Bottom
             end
-            r = _getfield_tfunc_const(sv, name, setfield)
+            r = _getfield_tfunc_const(sv, name)
             r !== nothing && return r
         end
         s00 = widenconst(s00)
@@ -976,9 +973,9 @@ function _getfield_tfunc(lattice::JLTypeLattice, @nospecialize(s00), @nospeciali
     end
     if isType(s)
         if isconstType(s)
-            sv = s00.parameters[1]
+            sv = (s00::DataType).parameters[1]
             if isa(name, Const)
-                r = _getfield_tfunc_const(sv, name, setfield)
+                r = _getfield_tfunc_const(sv, name)
                 r !== nothing && return r
             end
             s = typeof(sv)

base/compiler/typeutils.jl

@@ -24,12 +24,12 @@ function hasuniquerep(@nospecialize t)
 end
 
 """
-    isTypeDataType(@nospecialize t)
+    isTypeDataType(@nospecialize t) -> Bool
 
 For a type `t` test whether ∀S s.t. `isa(S, rewrap_unionall(Type{t}, ...))`,
 we have `isa(S, DataType)`. In particular, if a statement is typed as `Type{t}`
-(potentially wrapped in some UnionAll), then we are guaranteed that this statement
-will be a DataType at runtime (and not e.g. a Union or UnionAll typeequal to it).
+(potentially wrapped in some `UnionAll`), then we are guaranteed that this statement
+will be a `DataType` at runtime (and not e.g. a `Union` or `UnionAll` typeequal to it).
 """
 function isTypeDataType(@nospecialize t)
     isa(t, DataType) || return false
@@ -41,7 +41,7 @@ function isTypeDataType(@nospecialize t)
         # e.g. `Tuple{Union{Int, Float64}, Int}` is a DataType, but
         # `Union{Tuple{Int, Int}, Tuple{Float64, Int}}` is typeequal to it and
         # is not.
-        return _all(isTypeDataType, t.parameters)
+        return all(isTypeDataType, t.parameters)
     end
     return true
 end