diff options
Diffstat (limited to 'src/cmd/compile/internal/types2/testdata/examples/constraints.go2')
| -rw-r--r-- | src/cmd/compile/internal/types2/testdata/examples/constraints.go2 | 41 |
1 files changed, 36 insertions, 5 deletions
diff --git a/src/cmd/compile/internal/types2/testdata/examples/constraints.go2 b/src/cmd/compile/internal/types2/testdata/examples/constraints.go2 index 28aa19bb12..f40d18c63e 100644 --- a/src/cmd/compile/internal/types2/testdata/examples/constraints.go2 +++ b/src/cmd/compile/internal/types2/testdata/examples/constraints.go2 @@ -18,18 +18,25 @@ type ( } ) +type MyInt int + type ( // Arbitrary types may be embedded like interfaces. _ interface{int} _ interface{~int} // Types may be combined into a union. - _ interface{int|~string} + union interface{int|~string} - // Union terms must be unique independent of whether they are ~ or not. - _ interface{int|int /* ERROR duplicate term int */ } - _ interface{int|~ /* ERROR duplicate term int */ int } - _ interface{~int|~ /* ERROR duplicate term int */ int } + // Union terms must describe disjoint (non-overlapping) type sets. + _ interface{int|int /* ERROR overlapping terms int */ } + _ interface{int|~ /* ERROR overlapping terms ~int */ int } + _ interface{~int|~ /* ERROR overlapping terms ~int */ int } + _ interface{~int|MyInt /* ERROR overlapping terms p.MyInt and ~int */ } + _ interface{int|interface{}} + _ interface{int|~string|union} + _ interface{int|~string|interface{int}} + _ interface{union|union /* ERROR overlapping terms p.union and p.union */ } // For now we do not permit interfaces with methods in unions. _ interface{~ /* ERROR invalid use of ~ */ interface{}} @@ -45,6 +52,15 @@ type ( _ interface{~ /* ERROR invalid use of ~ */ bar } ) +// Stand-alone type parameters are not permitted as elements or terms in unions. +type ( + _[T interface{ *T } ] struct{} // ok + _[T interface{ int | *T } ] struct{} // ok + _[T interface{ T /* ERROR cannot embed a type parameter */ } ] struct{} + _[T interface{ ~T /* ERROR cannot embed a type parameter */ } ] struct{} + _[T interface{ int|T /* ERROR cannot embed a type parameter */ }] struct{} +) + // Multiple embedded union elements are intersected. The order in which they // appear in the interface doesn't matter since intersection is a symmetric // operation. @@ -58,3 +74,18 @@ func _[T interface{ ~int; myInt1|myInt2 }]() T { return T(0) } // Here the intersections are empty - there's no type that's in the type set of T. func _[T interface{ myInt1|myInt2; int }]() T { return T(0 /* ERROR cannot convert */ ) } func _[T interface{ int; myInt1|myInt2 }]() T { return T(0 /* ERROR cannot convert */ ) } + +// Union elements may be interfaces as long as they don't define +// any methods or embed comparable. + +type ( + Integer interface{ ~int|~int8|~int16|~int32|~int64 } + Unsigned interface{ ~uint|~uint8|~uint16|~uint32|~uint64 } + Floats interface{ ~float32|~float64 } + Complex interface{ ~complex64|~complex128 } + Number interface{ Integer|Unsigned|Floats|Complex } + Ordered interface{ Integer|Unsigned|Floats|~string } + + _ interface{ Number | error /* ERROR cannot use error in union */ } + _ interface{ Ordered | comparable /* ERROR cannot use comparable in union */ } +) |