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Diffstat (limited to 'test/typeparam/nested.go')
-rw-r--r-- | test/typeparam/nested.go | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/test/typeparam/nested.go b/test/typeparam/nested.go new file mode 100644 index 0000000..cdb8bfb --- /dev/null +++ b/test/typeparam/nested.go @@ -0,0 +1,134 @@ +// run + +// Copyright 2021 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// This test case stress tests a number of subtle cases involving +// nested type-parameterized declarations. At a high-level, it +// declares a generic function that contains a generic type +// declaration: +// +// func F[A intish]() { +// type T[B intish] struct{} +// +// // store reflect.Type tuple (A, B, F[A].T[B]) in tests +// } +// +// It then instantiates this function with a variety of type arguments +// for A and B. Particularly tricky things like shadowed types. +// +// From this data it tests two things: +// +// 1. Given tuples (A, B, F[A].T[B]) and (A', B', F[A'].T[B']), +// F[A].T[B] should be identical to F[A'].T[B'] iff (A, B) is +// identical to (A', B'). +// +// 2. A few of the instantiations are constructed to be identical, and +// it tests that exactly these pairs are duplicated (by golden +// output comparison to nested.out). +// +// In both cases, we're effectively using the compiler's existing +// runtime.Type handling (which is well tested) of type identity of A +// and B as a way to help bootstrap testing and validate its new +// runtime.Type handling of F[A].T[B]. +// +// This isn't perfect, but it smoked out a handful of issues in +// gotypes2 and unified IR. + +package main + +import ( + "fmt" + "reflect" +) + +type test struct { + TArgs [2]reflect.Type + Instance reflect.Type +} + +var tests []test + +type intish interface{ ~int } + +type Int int +type GlobalInt = Int // allow access to global Int, even when shadowed + +func F[A intish]() { + add := func(B, T interface{}) { + tests = append(tests, test{ + TArgs: [2]reflect.Type{ + reflect.TypeOf(A(0)), + reflect.TypeOf(B), + }, + Instance: reflect.TypeOf(T), + }) + } + + type Int int + + type T[B intish] struct{} + + add(int(0), T[int]{}) + add(Int(0), T[Int]{}) + add(GlobalInt(0), T[GlobalInt]{}) + add(A(0), T[A]{}) // NOTE: intentionally dups with int and GlobalInt + + type U[_ any] int + type V U[int] + type W V + + add(U[int](0), T[U[int]]{}) + add(U[Int](0), T[U[Int]]{}) + add(U[GlobalInt](0), T[U[GlobalInt]]{}) + add(U[A](0), T[U[A]]{}) // NOTE: intentionally dups with U[int] and U[GlobalInt] + add(V(0), T[V]{}) + add(W(0), T[W]{}) +} + +func main() { + type Int int + + F[int]() + F[Int]() + F[GlobalInt]() + + type U[_ any] int + type V U[int] + type W V + + F[U[int]]() + F[U[Int]]() + F[U[GlobalInt]]() + F[V]() + F[W]() + + type X[A any] U[X[A]] + + F[X[int]]() + F[X[Int]]() + F[X[GlobalInt]]() + + for j, tj := range tests { + for i, ti := range tests[:j+1] { + if (ti.TArgs == tj.TArgs) != (ti.Instance == tj.Instance) { + fmt.Printf("FAIL: %d,%d: %s, but %s\n", i, j, eq(ti.TArgs, tj.TArgs), eq(ti.Instance, tj.Instance)) + } + + // The test is constructed so we should see a few identical types. + // See "NOTE" comments above. + if i != j && ti.Instance == tj.Instance { + fmt.Printf("%d,%d: %v\n", i, j, ti.Instance) + } + } + } +} + +func eq(a, b interface{}) string { + op := "==" + if a != b { + op = "!=" + } + return fmt.Sprintf("%v %s %v", a, op, b) +} |