89e0a492af
This patch implements P0388R4, Permit conversions to arrays of unknown bound, <http://wg21.link/p0388r4>. CWG 393 allowed references to arrays of unknown bound and this C++20 feature allows conversions like void f(int(&)[]); int arr[1]; void g() { f(arr); } int(&r)[] = arr; The proposal seemed fairly straightforward but it turned out to be quite shifty. I found out that I needed to implement DR 2352 (done), and also DR 1307 (done in this patch). The latter DR added wording for list-initialization ranking of references to arrays which this proposal extends. DR 330 was also implemented in this patch. PR c++/91364 - P0388R4: Permit conversions to arrays of unknown bound. PR c++/69531 - DR 1307: Differently bounded array parameters. PR c++/88128 - DR 330: Qual convs and pointers to arrays of pointers. * call.c (build_array_conv): Build ck_identity at the beginning of the conversion. (standard_conversion): Pass bounds_none to comp_ptr_ttypes_const. (maybe_warn_array_conv): New. (convert_like_real): Call it. Add an error message about converting from arrays of unknown bounds. (conv_get_original_expr): New. (nelts_initialized_by_list_init): New. (conv_binds_to_array_of_unknown_bound): New. (compare_ics): Implement list-initialization ranking based on array sizes, as specified in DR 1307 and P0388R. * cp-tree.h (comp_ptr_ttypes_const): Adjust declaration. (compare_bounds_t): New enum. * typeck.c (comp_array_types): New bool and compare_bounds_t parameters. Use them. (structural_comptypes): Adjust the call to comp_array_types. (similar_type_p): Handle ARRAY_TYPE. (build_const_cast_1): Pass bounds_none to comp_ptr_ttypes_const. (comp_ptr_ttypes_real): Don't check cv-quals of ARRAY_TYPEs. Use comp_array_types to compare array types. Look through arrays as per DR 330. (comp_ptr_ttypes_const): Use comp_array_types to compare array types. Look through arrays as per DR 330. * g++.dg/conversion/qual1.C: New test. * g++.dg/conversion/qual2.C: New test. * g++.dg/conversion/qual3.C: New test. * g++.dg/conversion/ref2.C: New test. * g++.dg/conversion/ref3.C: New test. * g++.dg/cpp0x/initlist-array3.C: Remove dg-error. * g++.dg/cpp0x/initlist-array7.C: New test. * g++.dg/cpp0x/initlist-array8.C: New test. * g++.dg/cpp2a/array-conv1.C: New test. * g++.dg/cpp2a/array-conv10.C: New test. * g++.dg/cpp2a/array-conv11.C: New test. * g++.dg/cpp2a/array-conv12.C: New test. * g++.dg/cpp2a/array-conv13.C: New test. * g++.dg/cpp2a/array-conv14.C: New test. * g++.dg/cpp2a/array-conv15.C: New test. * g++.dg/cpp2a/array-conv16.C: New test. * g++.dg/cpp2a/array-conv17.C: New test. * g++.dg/cpp2a/array-conv2.C: New test. * g++.dg/cpp2a/array-conv3.C: New test. * g++.dg/cpp2a/array-conv4.C: New test. * g++.dg/cpp2a/array-conv5.C: New test. * g++.dg/cpp2a/array-conv6.C: New test. * g++.dg/cpp2a/array-conv7.C: New test. * g++.dg/cpp2a/array-conv8.C: New test. * g++.dg/cpp2a/array-conv9.C: New test. * g++.old-deja/g++.bugs/900321_01.C: Adjust dg-error. * testsuite/23_containers/span/lwg3255.cc: Adjust test to match the post-P0388R4 behavior. From-SVN: r276771
34 lines
1.4 KiB
C
34 lines
1.4 KiB
C
// PR c++/91364 - Implement P0388R4: Permit conversions to arrays of unknown bound.
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// { dg-do compile { target c++17 } }
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// { dg-options "-Wpedantic" }
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// C++17, because that has CWG 393.
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void f(int(&)[]);
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void fp(int(*)[]);
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void f2(int(&)[][10]);
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void fp2(int(*)[][10]);
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int arr[10];
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int arr2[10][10];
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void
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g ()
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{
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f (arr); // { dg-warning "conversions to arrays of unknown bound are only available" "" { target c++17_down } }
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fp (&arr); // { dg-warning "conversions to arrays of unknown bound are only available" "" { target c++17_down } }
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f2 (arr2);// { dg-warning "conversions to arrays of unknown bound are only available" "" { target c++17_down } }
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fp2 (&arr2);// { dg-warning "conversions to arrays of unknown bound are only available" "" { target c++17_down } }
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}
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int(&r1)[] = arr;// { dg-warning "conversions to arrays of unknown bound are only available" "" { target c++17_down } }
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int(&r2)[10] = arr;
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int(&r3)[][10] = arr2;// { dg-warning "conversions to arrays of unknown bound are only available" "" { target c++17_down } }
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/* Note that
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int (&r)[10][] = arr2;
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is invalid. */
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int(&r4)[10][10] = arr2;
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int(*p1)[] = &arr;// { dg-warning "conversions to arrays of unknown bound are only available" "" { target c++17_down } }
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int(*p2)[10] = &arr;
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int(*p3)[][10] = &arr2;// { dg-warning "conversions to arrays of unknown bound are only available" "" { target c++17_down } }
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int(*p4)[10][10] = &arr2;
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