fix some t-functions on PartialTuple arguments (#31014)

base/compiler/tfuncs.jl

@@ -299,6 +299,8 @@ function sizeof_nothrow(@nospecialize(x))
  x = x.val
  elseif isa(x, Conditional)
  return true
+ else
+ x = widenconst(x)
  end
  isconstType(x) && (x = x.parameters[1])
  if isa(x, Union)
@@ -325,13 +327,15 @@ function sizeof_tfunc(@nospecialize(x),)
  isa(x, Const) && return _const_sizeof(x.val)
  isa(x, Conditional) && return _const_sizeof(Bool)
  isconstType(x) && return _const_sizeof(x.parameters[1])
+ x = widenconst(x)
  x !== DataType && isconcretetype(x) && return _const_sizeof(x)
  return Int
 end
 add_tfunc(Core.sizeof, 1, 1, sizeof_tfunc, 0)
 function nfields_tfunc(@nospecialize(x))
  isa(x, Const) && return Const(nfields(x.val))
  isa(x, Conditional) && return Const(0)
+ x = widenconst(x)
  if isa(x, DataType) && !x.abstract && !(x.name === Tuple.name && isvatuple(x))
  if !(x.name === _NAMEDTUPLE_NAME && !isconcretetype(x))
  return Const(length(x.types))
@@ -470,12 +474,14 @@ function isa_tfunc(@nospecialize(v), @nospecialize(tt))
  if isexact && isnotbrokensubtype(v, t)
  return Const(true)
  end
- elseif isa(v, Const) || isa(v, Conditional) || isdispatchelem(v)
- # this tests for knowledge of a leaftype appearing on the LHS
- # (ensuring the isa is precise)
- return Const(false)
  else
+ if isa(v, Const) || isa(v, Conditional)
+ # this and the `isdispatchelem` below test for knowledge of a
+ # leaftype appearing on the LHS (ensuring the isa is precise)
+ return Const(false)
+ end
  v = widenconst(v)
+ isdispatchelem(v) && return Const(false)
  if typeintersect(v, t) === Bottom
  # similar to `isnotbrokensubtype` check above, `typeintersect(v, t)`
  # can't be trusted for kind types so we do an extra check here

test/compiler/inference.jl

@@ -1338,6 +1338,13 @@ let egal_tfunc
  @test egal_tfunc(Union{Int64, Float64}, AbstractArray) === Const(false)
 end
 
+using Core.Compiler: PartialTuple, nfields_tfunc, sizeof_tfunc, sizeof_nothrow
+let PT = PartialTuple(Tuple{Int64,UInt64}, Any[Const(10, false), UInt64])
+ @test sizeof_tfunc(PT) === Const(16, false)
+ @test nfields_tfunc(PT) === Const(2, false)
+ @test sizeof_nothrow(PT) === true
+end
+
 function f23024(::Type{T}, ::Int) where T
  1 + 1
 end