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MaxSagebaumMaxSagebaum
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Fix for downcast to parent. (#501)
* Fix for downcast to parent. * Regression tests for down and upcast in class hierarchy.
1 parent 5a252cc commit 92aa71e

7 files changed

+276
-4
lines changed

‎include/cpp2util.h

Lines changed: 16 additions & 4 deletions
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@@ -975,9 +975,15 @@ auto as( X const& x ) -> decltype(auto) {
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return x;
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}
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template< typename C, typename X >
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requires std::is_same_v<C, X>
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auto as( X& x ) -> decltype(auto) {
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return x;
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}
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template< typename C, typename X >
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auto as( X const& x ) -> auto
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requires (!std::is_same_v<C, X> && requires { C{x}; })
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requires (!std::is_same_v<C, X> && !std::is_base_of_v<C, X> && requires { C{x}; })
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{
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// Experiment: Recognize the nested `::value_type` pattern for some dynamic library types
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// like std::optional, and try to prevent accidental narrowing conversions even when
@@ -991,9 +997,15 @@ auto as( X const& x ) -> auto
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}
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template< typename C, typename X >
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requires std::is_base_of_v<C, X>
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auto as( X&& x ) -> C&& {
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return CPP2_FORWARD(x);
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requires (std::is_base_of_v<C, X> && !std::is_same_v<C, X>)
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auto as( X& x ) -> C& {
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return x;
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}
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template< typename C, typename X >
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requires (std::is_base_of_v<C, X> && !std::is_same_v<C, X>)
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auto as( X const& x ) -> C const& {
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return x;
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}
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template< typename C, typename X >

‎regression-tests/pure2-types-down-upcast.cpp2

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A: type = {
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public i: int = 0;
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const_foo: (virtual this) = { std::cout << "const foo \n"; }
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mut_foo: (inout this) = { std::cout << "foo \n"; }
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}
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B: type = {
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this: A = ();
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public d: double = 0.0;
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}
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func_mut: (inout a: A) -> void = { std::cout << "Call A mut: (a.i)$" << std::endl; }
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func_mut: (inout b: B) -> void = { std::cout << "Call B mut: (b.d)$" << std::endl; }
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func_const: (a: A) -> void = { std::cout << "Call A const: (a.i)$" << std::endl; }
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func_const: (b: B) -> void = { std::cout << "Call B const: (b.d)$" << std::endl; }
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test_const_foo: () = {
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s: A =();
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sC: *const A = s&;
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s.const_foo();
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sC*.const_foo();
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(s as A).const_foo();
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(sC* as A).const_foo();
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_ = s;
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_ = sC;
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}
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test_mut_foo: () = {
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s: A =();
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s.mut_foo();
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(s as A).mut_foo();
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_ = s;
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}
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test_up: () = {
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b: B = ();
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bC: *const B = b&;
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func_const(b);
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func_const(b as B);
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func_const(b as A);
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func_const(bC*);
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func_const(bC* as B);
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func_const(bC* as A);
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func_mut(b);
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func_mut(b as B);
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func_mut(b as A);
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_ = b;
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_ = bC;
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}
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test_down: () = {
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b: B = ();
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bC: *const B = b&;
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a: *A = (b as A)&;
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aC: *const A = (b as A)&;
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func_const(a*);
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func_const(a* as B);
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func_const(a* as A);
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func_const(aC*);
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func_const(aC* as B);
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func_const(aC* as A);
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func_mut(a*);
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func_mut(a* as B);
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func_mut(a* as A);
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_ = b;
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_ = bC;
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_ = a;
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_ = aC;
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}
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main: () -> int = {
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test_const_foo();
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test_mut_foo();
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test_up();
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test_down();
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return 0;
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}

‎regression-tests/test-results/gcc-10/pure2-types-down-upcast.cpp.execution

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const foo
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const foo
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const foo
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const foo
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foo
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foo
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Call B const: 0.000000
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Call B const: 0.000000
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Call A const: 0
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Call B const: 0.000000
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Call B const: 0.000000
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Call A const: 0
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Call B mut: 0.000000
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Call B mut: 0.000000
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Call A mut: 0
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Call A const: 0
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Call B const: 0.000000
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Call A const: 0
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Call A const: 0
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Call B const: 0.000000
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Call A const: 0
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Call A mut: 0
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Call B mut: 0.000000
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Call A mut: 0

‎regression-tests/test-results/gcc-10/pure2-types-down-upcast.cpp.output

Whitespace-only changes.

‎regression-tests/test-results/pure2-types-down-upcast.cpp

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#define CPP2_USE_MODULES Yes
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//=== Cpp2 type declarations ====================================================
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#include "cpp2util.h"
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#line 1 "pure2-types-down-upcast.cpp2"
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class A;
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#line 8 "pure2-types-down-upcast.cpp2"
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class B;
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//=== Cpp2 type definitions and function declarations ===========================
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#line 1 "pure2-types-down-upcast.cpp2"
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class A {
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public: int i {0};
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public: virtual auto const_foo() const -> void;
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public: auto mut_foo() -> void;
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public: A() = default;
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public: A(A const&) = delete; /* No 'that' constructor, suppress copy */
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public: auto operator=(A const&) -> void = delete;
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#line 6 "pure2-types-down-upcast.cpp2"
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};
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class B: public A {
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public: double d {0.0};
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public: B() = default;
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public: B(B const&) = delete; /* No 'that' constructor, suppress copy */
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public: auto operator=(B const&) -> void = delete;
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#line 11 "pure2-types-down-upcast.cpp2"
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};
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auto func_mut(A& a) -> void;
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auto func_mut(B& b) -> void;
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auto func_const(cpp2::in<A> a) -> void;
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auto func_const(cpp2::in<B> b) -> void;
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auto test_const_foo() -> void;
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#line 29 "pure2-types-down-upcast.cpp2"
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auto test_mut_foo() -> void;
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#line 36 "pure2-types-down-upcast.cpp2"
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auto test_up() -> void;
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#line 55 "pure2-types-down-upcast.cpp2"
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auto test_down() -> void;
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#line 77 "pure2-types-down-upcast.cpp2"
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[[nodiscard]] auto main() -> int;
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//=== Cpp2 function definitions =================================================
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#line 4 "pure2-types-down-upcast.cpp2"
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auto A::const_foo() const -> void{std::cout << "const foo \n"; }
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auto A::mut_foo() -> void{std::cout << "foo \n"; }
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#line 13 "pure2-types-down-upcast.cpp2"
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auto func_mut(A& a) -> void {std::cout << "Call A mut: " + cpp2::to_string(a.i) << std::endl;}
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auto func_mut(B& b) -> void {std::cout << "Call B mut: " + cpp2::to_string(b.d) << std::endl;}
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auto func_const(cpp2::in<A> a) -> void{std::cout << "Call A const: " + cpp2::to_string(a.i) << std::endl;}
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auto func_const(cpp2::in<B> b) -> void{std::cout << "Call B const: " + cpp2::to_string(b.d) << std::endl;}
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auto test_const_foo() -> void{
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A s {};
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A const* sC {&s};
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CPP2_UFCS_0(const_foo, s);
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CPP2_UFCS_0(const_foo, (*cpp2::assert_not_null(sC)));
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CPP2_UFCS_0(const_foo, (cpp2::as_<A>(s)));
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CPP2_UFCS_0(const_foo, (cpp2::as_<A>(*cpp2::assert_not_null(sC))));
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(void) std::move(s);
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(void) std::move(sC);
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}
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auto test_mut_foo() -> void{
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A s {};
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CPP2_UFCS_0(mut_foo, s);
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CPP2_UFCS_0(mut_foo, (cpp2::as_<A>(s)));
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(void) std::move(s);
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}
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auto test_up() -> void{
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B b {};
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B const* bC {&b};
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func_const(b);
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func_const(cpp2::as_<B>(b));
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func_const(cpp2::as_<A>(b));
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func_const(*cpp2::assert_not_null(bC));
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func_const(cpp2::as_<B>(*cpp2::assert_not_null(bC)));
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func_const(cpp2::as_<A>(*cpp2::assert_not_null(bC)));
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func_mut(b);
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func_mut(cpp2::as_<B>(b));
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func_mut(cpp2::as_<A>(b));
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(void) std::move(b);
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(void) std::move(bC);
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}
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auto test_down() -> void{
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B b {};
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B const* bC {&b};
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A* a {&(cpp2::as_<A>(b))};
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A const* aC {&(cpp2::as_<A>(b))};
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func_const(*cpp2::assert_not_null(a));
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func_const(cpp2::as_<B>(*cpp2::assert_not_null(a)));
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func_const(cpp2::as_<A>(*cpp2::assert_not_null(a)));
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func_const(*cpp2::assert_not_null(aC));
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func_const(cpp2::as_<B>(*cpp2::assert_not_null(aC)));
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func_const(cpp2::as_<A>(*cpp2::assert_not_null(aC)));
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func_mut(*cpp2::assert_not_null(a));
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func_mut(cpp2::as_<B>(*cpp2::assert_not_null(a)));
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func_mut(cpp2::as_<A>(*cpp2::assert_not_null(a)));
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(void) std::move(b);
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(void) std::move(bC);
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(void) std::move(a);
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(void) std::move(aC);
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}
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[[nodiscard]] auto main() -> int{
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test_const_foo();
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test_mut_foo();
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test_up();
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test_down();
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return 0;
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}
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‎regression-tests/test-results/pure2-types-down-upcast.cpp2

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pure2-types-down-upcast.cpp2... ok (all Cpp2, passes safety checks)
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‎regression-tests/test-results/pure2-types-down-upcast.cpp2.output

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pure2-types-down-upcast.cpp2... ok (all Cpp2, passes safety checks)
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