753b4679bc
This patch nails down the remaining P0960 case in PR92812:
struct A {
int ar[2];
A(): ar(1, 2) {} // doesn't work without this patch
};
Note that when the target object is not of array type, this already
works:
struct S { int x, y; };
struct A {
S s;
A(): s(1, 2) { } // OK in C++20
};
because build_new_method_call_1 takes care of the P0960 magic.
It proved to be quite hairy. When the ()-list has more than one
element, we can always create a CONSTRUCTOR, because the code was
previously invalid. But when the ()-list has just one element, it
gets all kinds of difficult. As usual, we have to handle a("foo")
so as not to wrap the STRING_CST in a CONSTRUCTOR. Always turning
x(e) into x{e} would run into trouble as in c++/93790. Another
issue was what to do about x({e}): previously, this would trigger
"list-initializer for non-class type must not be parenthesized".
I figured I'd make this work in C++20, so that given
struct S { int x, y; };
you can do
S a[2];
[...]
A(): a({1, 2}) // initialize a[0] with {1, 2} and a[1] with {}
It also turned out that, as an extension, we support compound literals:
F (): m((S[1]) { 1, 2 })
so this has to keep working as before. Moreover, make sure not to trigger
in compiler-generated code, like =default, where array assignment is allowed.
I've factored out a function that turns a TREE_LIST into a CONSTRUCTOR
to simplify handling of P0960.
paren-init35.C also tests this with vector types.
gcc/cp/ChangeLog:
PR c++/92812
* cp-tree.h (do_aggregate_paren_init): Declare.
* decl.c (do_aggregate_paren_init): New.
(grok_reference_init): Use it.
(check_initializer): Likewise.
* init.c (perform_member_init): Handle initializing an array from
a ()-list. Use do_aggregate_paren_init.
gcc/testsuite/ChangeLog:
PR c++/92812
* g++.dg/cpp0x/constexpr-array23.C: Adjust dg-error.
* g++.dg/cpp0x/initlist69.C: Likewise.
* g++.dg/diagnostic/mem-init1.C: Likewise.
* g++.dg/init/array28.C: Likewise.
* g++.dg/cpp2a/paren-init33.C: New test.
* g++.dg/cpp2a/paren-init34.C: New test.
* g++.dg/cpp2a/paren-init35.C: New test.
* g++.old-deja/g++.brendan/crash60.C: Adjust dg-error.
* g++.old-deja/g++.law/init10.C: Likewise.
* g++.old-deja/g++.other/array3.C: Likewise.
25 lines
370 B
C
25 lines
370 B
C
// PR c++/86917
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// { dg-do compile { target c++11 } }
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struct A
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{
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constexpr A () : c (0) {}
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static const A z;
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unsigned c;
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};
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struct B
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{
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typedef A W[4]; // { dg-error "paren" "" { target { ! c++20 } } .+1 }
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constexpr B () : w ({ A::z, A::z, A::z, A::z }) {} // { dg-error "constant|could not convert" }
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W w;
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};
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struct C
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{
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C ();
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B w[1];
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};
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C::C () { }
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