diff --git a/base/compiler/abstractinterpretation.jl b/base/compiler/abstractinterpretation.jl
index 4ebe377e091e6..8275c2e6865da 100644
--- a/base/compiler/abstractinterpretation.jl
+++ b/base/compiler/abstractinterpretation.jl
@@ -2044,6 +2044,7 @@ function form_partially_defined_struct(@nospecialize(obj), @nospecialize(name))
     name isa Const || return nothing
     objt0 = widenconst(obj)
     objt = unwrap_unionall(objt0)
+    objt isa DataType || return nothing
     isabstracttype(objt) && return nothing
     fldidx = try_compute_fieldidx(objt, name.val)
     fldidx === nothing && return nothing
@@ -3109,7 +3110,8 @@ end
 @nospecializeinfer function widenreturn_partials(𝕃ᵢ::PartialsLattice, @nospecialize(rt), info::BestguessInfo)
     if isa(rt, PartialStruct)
         fields = copy(rt.fields)
-        anyrefine = !isvarargtype(rt.fields[end]) && length(rt.fields) > datatype_min_ninitialized(rt.typ)
+        anyrefine = !isvarargtype(rt.fields[end]) &&
+            length(rt.fields) > datatype_min_ninitialized(unwrap_unionall(rt.typ))
         𝕃 = typeinf_lattice(info.interp)
         ⊏ = strictpartialorder(𝕃)
         for i in 1:length(fields)
diff --git a/base/compiler/tfuncs.jl b/base/compiler/tfuncs.jl
index 2af729ceec473..f1e3b550f67db 100644
--- a/base/compiler/tfuncs.jl
+++ b/base/compiler/tfuncs.jl
@@ -1005,7 +1005,7 @@ end
             nflds = nfields(sv)
             ismod = sv isa Module
         elseif isa(s00, PartialStruct)
-            sty = s00.typ
+            sty = unwrap_unionall(s00.typ)
             nflds = fieldcount_noerror(sty)
             ismod = false
         else
diff --git a/test/tuple.jl b/test/tuple.jl
index 59897c8adfdb2..f7481cc4f5150 100644
--- a/test/tuple.jl
+++ b/test/tuple.jl
@@ -533,7 +533,7 @@ end
         @test ntuple(identity, Val(n)) == ntuple(identity, n)
     end
 
-    @test Core.Compiler.return_type(ntuple, Tuple{typeof(identity), Val}) == Tuple{Vararg{Int}}
+    @test Base.infer_return_type(ntuple, Tuple{typeof(identity), Val}) == Tuple{Vararg{Int}}
 end
 
 struct A_15703{N}
@@ -835,8 +835,8 @@ end
     @test @inferred(Base.circshift(t3, 7)) == ('b', 'c', 'd', 'a')
     @test @inferred(Base.circshift(t3, -1)) == ('b', 'c', 'd', 'a')
     @test_throws MethodError circshift(t1, 'a')
-    @test Core.Compiler.return_type(circshift, Tuple{Tuple,Integer}) <: Tuple
-    @test Core.Compiler.return_type(circshift, Tuple{Tuple{Vararg{Any,10}},Integer}) <: Tuple{Vararg{Any,10}}
+    @test Base.infer_return_type(circshift, Tuple{Tuple,Integer}) <: Tuple
+    @test Base.infer_return_type(circshift, Tuple{Tuple{Vararg{Any,10}},Integer}) <: Tuple{Vararg{Any,10}}
     for len ∈ 0:5
         v = 1:len
         t = Tuple(v)
@@ -847,8 +847,8 @@ end
 end
 
 @testset "abstract return type inference for homogeneous tuples" begin
-    @test NTuple == Core.Compiler.return_type(Base.tail, Tuple{NTuple})
-    @test NTuple == Core.Compiler.return_type(Base.front, Tuple{NTuple})
-    @test NTuple == Core.Compiler.return_type(reverse, Tuple{NTuple})
-    @test NTuple == Core.Compiler.return_type(circshift, Tuple{NTuple,Int})
+    @test NTuple == Base.infer_return_type(Base.tail, Tuple{NTuple})
+    @test NTuple == Base.infer_return_type(Base.front, Tuple{NTuple})
+    @test NTuple == Base.infer_return_type(reverse, Tuple{NTuple})
+    @test NTuple == Base.infer_return_type(circshift, Tuple{NTuple,Int})
 end