improve the effects of Base._tuple_unique_fieldtypes

Discovered during inspecting #48097.
JuliaLang · Jan 4, 2023 · 69f41e1 · 69f41e1
1 parent 52af407
commit 69f41e1
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Showing 2 changed files with 8 additions and 6 deletions.
diff --git a/base/essentials.jl b/base/essentials.jl
@@ -386,8 +386,10 @@ function isvatuple(@nospecialize(t))
     return false
 end
 
-unwrapva(t::Core.TypeofVararg) = isdefined(t, :T) ? t.T : Any
-unwrapva(@nospecialize(t)) = t
+function unwrapva(@nospecialize(t))
+    isa(t, Core.TypeofVararg) || return t
+    return isdefined(t, :T) ? t.T : Any
+end
 
 function unconstrain_vararg_length(va::Core.TypeofVararg)
     # construct a new Vararg type where its length is unconstrained,

diff --git a/base/tuple.jl b/base/tuple.jl
@@ -208,15 +208,15 @@ eltype(t::Type{<:Tuple}) = _compute_eltype(t)
 function _tuple_unique_fieldtypes(@nospecialize t)
     @_total_meta
     types = IdSet()
-    t´ = unwrap_unionall(t)
     # Given t = Tuple{Vararg{S}} where S<:Real, the various
     # unwrapping/wrapping/va-handling here will return Real
     if t isa Union
-        union!(types, _tuple_unique_fieldtypes(rewrap_unionall(t´.a, t)))
-        union!(types, _tuple_unique_fieldtypes(rewrap_unionall(t´.b, t)))
+        union!(types, _tuple_unique_fieldtypes(rewrap_unionall(t.a, t)))
+        union!(types, _tuple_unique_fieldtypes(rewrap_unionall(t.b, t)))
     else
         r = Union{}
-        for ti in (t´::DataType).parameters
+        t´ = unwrap_unionall(t)::DataType
+        for ti in t´.parameters
             r = push!(types, rewrap_unionall(unwrapva(ti), t))
         end
     end