mono_test.go

     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  	"bytes"
     9  	"errors"
    10  	"fmt"
    11  	"go/ast"
    12  	"go/importer"
    13  	"go/parser"
    14  	"go/token"
    15  	"go/types"
    16  	"strings"
    17  	"testing"
    18  )
    19  
    20  func checkMono(t *testing.T, body string) error {
    21  	fset := token.NewFileSet()
    22  	file, err := parser.ParseFile(fset, "x.go", "package x; import `unsafe`; var _ unsafe.Pointer;\n"+body, 0)
    23  	if err != nil {
    24  		t.Fatal(err)
    25  	}
    26  	files := []*ast.File{file}
    27  
    28  	var buf bytes.Buffer
    29  	conf := types.Config{
    30  		Error:    func(err error) { fmt.Fprintln(&buf, err) },
    31  		Importer: importer.Default(),
    32  	}
    33  	conf.Check("x", fset, files, nil)
    34  	if buf.Len() == 0 {
    35  		return nil
    36  	}
    37  	return errors.New(strings.TrimRight(buf.String(), "\n"))
    38  }
    39  
    40  func TestMonoGood(t *testing.T) {
    41  	for i, good := range goods {
    42  		if err := checkMono(t, good); err != nil {
    43  			t.Errorf("%d: unexpected failure: %v", i, err)
    44  		}
    45  	}
    46  }
    47  
    48  func TestMonoBad(t *testing.T) {
    49  	for i, bad := range bads {
    50  		if err := checkMono(t, bad); err == nil {
    51  			t.Errorf("%d: unexpected success", i)
    52  		} else {
    53  			t.Log(err)
    54  		}
    55  	}
    56  }
    57  
    58  var goods = []string{
    59  	"func F[T any](x T) { F(x) }",
    60  	"func F[T, U, V any]() { F[U, V, T](); F[V, T, U]() }",
    61  	"type Ring[A, B, C any] struct { L *Ring[B, C, A]; R *Ring[C, A, B] }",
    62  	"func F[T any]() { type U[T any] [unsafe.Sizeof(F[*T])]byte }",
    63  	"func F[T any]() { type U[T any] [unsafe.Sizeof(F[*T])]byte; var _ U[int] }",
    64  	"type U[T any] [unsafe.Sizeof(F[*T])]byte; func F[T any]() { var _ U[U[int]] }",
    65  	"func F[T any]() { type A = int; F[A]() }",
    66  }
    67  
    68  // TODO(mdempsky): Validate specific error messages and positioning.
    69  
    70  var bads = []string{
    71  	"func F[T any](x T) { F(&x) }",
    72  	"func F[T any]() { F[*T]() }",
    73  	"func F[T any]() { F[[]T]() }",
    74  	"func F[T any]() { F[[1]T]() }",
    75  	"func F[T any]() { F[chan T]() }",
    76  	"func F[T any]() { F[map[*T]int]() }",
    77  	"func F[T any]() { F[map[error]T]() }",
    78  	"func F[T any]() { F[func(T)]() }",
    79  	"func F[T any]() { F[func() T]() }",
    80  	"func F[T any]() { F[struct{ t T }]() }",
    81  	"func F[T any]() { F[interface{ t() T }]() }",
    82  	"type U[_ any] int; func F[T any]() { F[U[T]]() }",
    83  	"func F[T any]() { type U int; F[U]() }",
    84  	"func F[T any]() { type U int; F[*U]() }",
    85  	"type U[T any] int; func (U[T]) m() { var _ U[*T] }",
    86  	"type U[T any] int; func (*U[T]) m() { var _ U[*T] }",
    87  	"type U[T1 any] [unsafe.Sizeof(F[*T1])]byte; func F[T2 any]() { var _ U[T2] }",
    88  	"func F[A, B, C, D, E any]() { F[B, C, D, E, *A]() }",
    89  	"type U[_ any] int; const X = unsafe.Sizeof(func() { type A[T any] U[A[*T]] })",
    90  	"func F[T any]() { type A = *T; F[A]() }",
    91  	"type A[T any] struct { _ A[*T] }",
    92  }
    93
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