prevent stack overflows from user-defined constructor methods: strings#60876
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adienes merged 1 commit intoJuliaLang:masterfrom Jan 30, 2026
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Due to issue JuliaLang#42372, it can not be assumed that a constructor call will return a value of the requested type. Enforce that assumption in code where it matters. Example stack overflows that this change prevents: ```julia struct FaultyInt <: Integer end # new `Int`-like function Base.Int(x::FaultyInt) x end # invalid constructor iterate("", FaultyInt()) # overflows the stack isvalid("", FaultyInt()) # overflows the stack struct MyString <: AbstractString # valid new subtype of `AbstractString` str::String end isvalid(MyString(""), FaultyInt()) # overflows the stack codeunit(MyString(""), FaultyInt()) # overflows the stack ``` Follow up on PR JuliaLang#59506.
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Due to issue #42372, it can not be assumed that a constructor call will return a value of the requested type. Enforce that assumption in code where it matters.
Example stack overflows that this change prevents:
Follow up on PR #59506.