mono_test.go raw

   1  // Copyright 2021 The Go Authors. All rights reserved.
   2  // Use of this source code is governed by a BSD-style
   3  // license that can be found in the LICENSE file.
   4  
   5  package types_test
   6  
   7  import (
   8  	"errors"
   9  	"fmt"
  10  	"go/types"
  11  	"strings"
  12  	"testing"
  13  )
  14  
  15  func checkMono(t *testing.T, body string) error {
  16  	src := "package x; import `unsafe`; var _ unsafe.Pointer;\n" + body
  17  
  18  	var buf strings.Builder
  19  	conf := types.Config{
  20  		Error:    func(err error) { fmt.Fprintln(&buf, err) },
  21  		Importer: defaultImporter(fset), // TODO(adonovan): use same FileSet as typecheck
  22  	}
  23  	typecheck(src, &conf, nil)
  24  	if buf.Len() == 0 {
  25  		return nil
  26  	}
  27  	return errors.New(strings.TrimRight(buf.String(), "\n"))
  28  }
  29  
  30  func TestMonoGood(t *testing.T) {
  31  	for i, good := range goods {
  32  		if err := checkMono(t, good); err != nil {
  33  			t.Errorf("%d: unexpected failure: %v", i, err)
  34  		}
  35  	}
  36  }
  37  
  38  func TestMonoBad(t *testing.T) {
  39  	for i, bad := range bads {
  40  		if err := checkMono(t, bad); err == nil {
  41  			t.Errorf("%d: unexpected success", i)
  42  		} else {
  43  			t.Log(err)
  44  		}
  45  	}
  46  }
  47  
  48  var goods = []string{
  49  	"func F[T any](x T) { F(x) }",
  50  	"func F[T, U, V any]() { F[U, V, T](); F[V, T, U]() }",
  51  	"type Ring[A, B, C any] struct { L *Ring[B, C, A]; R *Ring[C, A, B] }",
  52  	"func F[T any]() { type U[T any] [unsafe.Sizeof(F[*T])]byte }",
  53  	"func F[T any]() { type U[T any] [unsafe.Sizeof(F[*T])]byte; var _ U[int] }",
  54  	"type U[T any] [unsafe.Sizeof(F[*T])]byte; func F[T any]() { var _ U[U[int]] }",
  55  	"func F[T any]() { type A = int; F[A]() }",
  56  }
  57  
  58  // TODO(mdempsky): Validate specific error messages and positioning.
  59  
  60  var bads = []string{
  61  	"func F[T any](x T) { F(&x) }",
  62  	"func F[T any]() { F[*T]() }",
  63  	"func F[T any]() { F[[]T]() }",
  64  	"func F[T any]() { F[[1]T]() }",
  65  	"func F[T any]() { F[chan T]() }",
  66  	"func F[T any]() { F[map[*T]int]() }",
  67  	"func F[T any]() { F[map[error]T]() }",
  68  	"func F[T any]() { F[func(T)]() }",
  69  	"func F[T any]() { F[func() T]() }",
  70  	"func F[T any]() { F[struct{ t T }]() }",
  71  	"func F[T any]() { F[interface{ t() T }]() }",
  72  	"type U[_ any] int; func F[T any]() { F[U[T]]() }",
  73  	"func F[T any]() { type U int; F[U]() }",
  74  	"func F[T any]() { type U int; F[*U]() }",
  75  	"type U[T any] int; func (U[T]) m() { var _ U[*T] }",
  76  	"type U[T any] int; func (*U[T]) m() { var _ U[*T] }",
  77  	"type U[T1 any] [unsafe.Sizeof(F[*T1])]byte; func F[T2 any]() { var _ U[T2] }",
  78  	"func F[A, B, C, D, E any]() { F[B, C, D, E, *A]() }",
  79  	"type U[_ any] int; const X = unsafe.Sizeof(func() { type A[T any] U[A[*T]] })",
  80  	"func F[T any]() { type A = *T; F[A]() }",
  81  	"type A[T any] struct { _ A[*T] }",
  82  }
  83