libgo: update to go1.9

[official-gcc.git] / libgo / go / go / types / api_test.go

// Copyright 2013 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.

package types_test

import (
        "bytes"
        "fmt"
        "go/ast"
        "go/importer"
        "go/parser"
        "go/token"
        "internal/testenv"
        "reflect"
        "regexp"
        "strings"
        "testing"

        . "go/types"
)

func pkgFor(path, source string, info *Info) (*Package, error) {
        fset := token.NewFileSet()
        f, err := parser.ParseFile(fset, path, source, 0)
        if err != nil {
                return nil, err
        }

        conf := Config{Importer: importer.Default()}
        return conf.Check(f.Name.Name, fset, []*ast.File{f}, info)
}

func mustTypecheck(t *testing.T, path, source string, info *Info) string {
        t.Skip("skipping for gccgo--no importer")
        pkg, err := pkgFor(path, source, info)
        if err != nil {
                name := path
                if pkg != nil {
                        name = "package " + pkg.Name()
                }
                t.Fatalf("%s: didn't type-check (%s)", name, err)
        }
        return pkg.Name()
}

func TestValuesInfo(t *testing.T) {
        var tests = []struct {
                src  string
                expr string // constant expression
                typ  string // constant type
                val  string // constant value
        }{
                {`package a0; const _ = false`, `false`, `untyped bool`, `false`},
                {`package a1; const _ = 0`, `0`, `untyped int`, `0`},
                {`package a2; const _ = 'A'`, `'A'`, `untyped rune`, `65`},
                {`package a3; const _ = 0.`, `0.`, `untyped float`, `0`},
                {`package a4; const _ = 0i`, `0i`, `untyped complex`, `(0 + 0i)`},
                {`package a5; const _ = "foo"`, `"foo"`, `untyped string`, `"foo"`},

                {`package b0; var _ = false`, `false`, `bool`, `false`},
                {`package b1; var _ = 0`, `0`, `int`, `0`},
                {`package b2; var _ = 'A'`, `'A'`, `rune`, `65`},
                {`package b3; var _ = 0.`, `0.`, `float64`, `0`},
                {`package b4; var _ = 0i`, `0i`, `complex128`, `(0 + 0i)`},
                {`package b5; var _ = "foo"`, `"foo"`, `string`, `"foo"`},

                {`package c0a; var _ = bool(false)`, `false`, `bool`, `false`},
                {`package c0b; var _ = bool(false)`, `bool(false)`, `bool`, `false`},
                {`package c0c; type T bool; var _ = T(false)`, `T(false)`, `c0c.T`, `false`},

                {`package c1a; var _ = int(0)`, `0`, `int`, `0`},
                {`package c1b; var _ = int(0)`, `int(0)`, `int`, `0`},
                {`package c1c; type T int; var _ = T(0)`, `T(0)`, `c1c.T`, `0`},

                {`package c2a; var _ = rune('A')`, `'A'`, `rune`, `65`},
                {`package c2b; var _ = rune('A')`, `rune('A')`, `rune`, `65`},
                {`package c2c; type T rune; var _ = T('A')`, `T('A')`, `c2c.T`, `65`},

                {`package c3a; var _ = float32(0.)`, `0.`, `float32`, `0`},
                {`package c3b; var _ = float32(0.)`, `float32(0.)`, `float32`, `0`},
                {`package c3c; type T float32; var _ = T(0.)`, `T(0.)`, `c3c.T`, `0`},

                {`package c4a; var _ = complex64(0i)`, `0i`, `complex64`, `(0 + 0i)`},
                {`package c4b; var _ = complex64(0i)`, `complex64(0i)`, `complex64`, `(0 + 0i)`},
                {`package c4c; type T complex64; var _ = T(0i)`, `T(0i)`, `c4c.T`, `(0 + 0i)`},

                {`package c5a; var _ = string("foo")`, `"foo"`, `string`, `"foo"`},
                {`package c5b; var _ = string("foo")`, `string("foo")`, `string`, `"foo"`},
                {`package c5c; type T string; var _ = T("foo")`, `T("foo")`, `c5c.T`, `"foo"`},

                {`package d0; var _ = []byte("foo")`, `"foo"`, `string`, `"foo"`},
                {`package d1; var _ = []byte(string("foo"))`, `"foo"`, `string`, `"foo"`},
                {`package d2; var _ = []byte(string("foo"))`, `string("foo")`, `string`, `"foo"`},
                {`package d3; type T []byte; var _ = T("foo")`, `"foo"`, `string`, `"foo"`},

                {`package e0; const _ = float32( 1e-200)`, `float32(1e-200)`, `float32`, `0`},
                {`package e1; const _ = float32(-1e-200)`, `float32(-1e-200)`, `float32`, `0`},
                {`package e2; const _ = float64( 1e-2000)`, `float64(1e-2000)`, `float64`, `0`},
                {`package e3; const _ = float64(-1e-2000)`, `float64(-1e-2000)`, `float64`, `0`},
                {`package e4; const _ = complex64( 1e-200)`, `complex64(1e-200)`, `complex64`, `(0 + 0i)`},
                {`package e5; const _ = complex64(-1e-200)`, `complex64(-1e-200)`, `complex64`, `(0 + 0i)`},
                {`package e6; const _ = complex128( 1e-2000)`, `complex128(1e-2000)`, `complex128`, `(0 + 0i)`},
                {`package e7; const _ = complex128(-1e-2000)`, `complex128(-1e-2000)`, `complex128`, `(0 + 0i)`},

                {`package f0 ; var _ float32 =  1e-200`, `1e-200`, `float32`, `0`},
                {`package f1 ; var _ float32 = -1e-200`, `-1e-200`, `float32`, `0`},
                {`package f2a; var _ float64 =  1e-2000`, `1e-2000`, `float64`, `0`},
                {`package f3a; var _ float64 = -1e-2000`, `-1e-2000`, `float64`, `0`},
                {`package f2b; var _         =  1e-2000`, `1e-2000`, `float64`, `0`},
                {`package f3b; var _         = -1e-2000`, `-1e-2000`, `float64`, `0`},
                {`package f4 ; var _ complex64  =  1e-200 `, `1e-200`, `complex64`, `(0 + 0i)`},
                {`package f5 ; var _ complex64  = -1e-200 `, `-1e-200`, `complex64`, `(0 + 0i)`},
                {`package f6a; var _ complex128 =  1e-2000i`, `1e-2000i`, `complex128`, `(0 + 0i)`},
                {`package f7a; var _ complex128 = -1e-2000i`, `-1e-2000i`, `complex128`, `(0 + 0i)`},
                {`package f6b; var _            =  1e-2000i`, `1e-2000i`, `complex128`, `(0 + 0i)`},
                {`package f7b; var _            = -1e-2000i`, `-1e-2000i`, `complex128`, `(0 + 0i)`},
        }

        for _, test := range tests {
                info := Info{
                        Types: make(map[ast.Expr]TypeAndValue),
                }
                name := mustTypecheck(t, "ValuesInfo", test.src, &info)

                // look for constant expression
                var expr ast.Expr
                for e := range info.Types {
                        if ExprString(e) == test.expr {
                                expr = e
                                break
                        }
                }
                if expr == nil {
                        t.Errorf("package %s: no expression found for %s", name, test.expr)
                        continue
                }
                tv := info.Types[expr]

                // check that type is correct
                if got := tv.Type.String(); got != test.typ {
                        t.Errorf("package %s: got type %s; want %s", name, got, test.typ)
                        continue
                }

                // check that value is correct
                if got := tv.Value.ExactString(); got != test.val {
                        t.Errorf("package %s: got value %s; want %s", name, got, test.val)
                }
        }
}

func TestTypesInfo(t *testing.T) {
        var tests = []struct {
                src  string
                expr string // expression
                typ  string // value type
        }{
                // single-valued expressions of untyped constants
                {`package b0; var x interface{} = false`, `false`, `bool`},
                {`package b1; var x interface{} = 0`, `0`, `int`},
                {`package b2; var x interface{} = 0.`, `0.`, `float64`},
                {`package b3; var x interface{} = 0i`, `0i`, `complex128`},
                {`package b4; var x interface{} = "foo"`, `"foo"`, `string`},

                // comma-ok expressions
                {`package p0; var x interface{}; var _, _ = x.(int)`,
                        `x.(int)`,
                        `(int, bool)`,
                },
                {`package p1; var x interface{}; func _() { _, _ = x.(int) }`,
                        `x.(int)`,
                        `(int, bool)`,
                },
                {`package p2a; type mybool bool; var m map[string]complex128; var b mybool; func _() { _, b = m["foo"] }`,
                        `m["foo"]`,
                        `(complex128, p2a.mybool)`,
                },
                {`package p2b; var m map[string]complex128; var b bool; func _() { _, b = m["foo"] }`,
                        `m["foo"]`,
                        `(complex128, bool)`,
                },
                {`package p3; var c chan string; var _, _ = <-c`,
                        `<-c`,
                        `(string, bool)`,
                },

                // issue 6796
                {`package issue6796_a; var x interface{}; var _, _ = (x.(int))`,
                        `x.(int)`,
                        `(int, bool)`,
                },
                {`package issue6796_b; var c chan string; var _, _ = (<-c)`,
                        `(<-c)`,
                        `(string, bool)`,
                },
                {`package issue6796_c; var c chan string; var _, _ = (<-c)`,
                        `<-c`,
                        `(string, bool)`,
                },
                {`package issue6796_d; var c chan string; var _, _ = ((<-c))`,
                        `(<-c)`,
                        `(string, bool)`,
                },
                {`package issue6796_e; func f(c chan string) { _, _ = ((<-c)) }`,
                        `(<-c)`,
                        `(string, bool)`,
                },

                // issue 7060
                {`package issue7060_a; var ( m map[int]string; x, ok = m[0] )`,
                        `m[0]`,
                        `(string, bool)`,
                },
                {`package issue7060_b; var ( m map[int]string; x, ok interface{} = m[0] )`,
                        `m[0]`,
                        `(string, bool)`,
                },
                {`package issue7060_c; func f(x interface{}, ok bool, m map[int]string) { x, ok = m[0] }`,
                        `m[0]`,
                        `(string, bool)`,
                },
                {`package issue7060_d; var ( ch chan string; x, ok = <-ch )`,
                        `<-ch`,
                        `(string, bool)`,
                },
                {`package issue7060_e; var ( ch chan string; x, ok interface{} = <-ch )`,
                        `<-ch`,
                        `(string, bool)`,
                },
                {`package issue7060_f; func f(x interface{}, ok bool, ch chan string) { x, ok = <-ch }`,
                        `<-ch`,
                        `(string, bool)`,
                },
        }

        for _, test := range tests {
                info := Info{Types: make(map[ast.Expr]TypeAndValue)}
                name := mustTypecheck(t, "TypesInfo", test.src, &info)

                // look for expression type
                var typ Type
                for e, tv := range info.Types {
                        if ExprString(e) == test.expr {
                                typ = tv.Type
                                break
                        }
                }
                if typ == nil {
                        t.Errorf("package %s: no type found for %s", name, test.expr)
                        continue
                }

                // check that type is correct
                if got := typ.String(); got != test.typ {
                        t.Errorf("package %s: got %s; want %s", name, got, test.typ)
                }
        }
}

func predString(tv TypeAndValue) string {
        var buf bytes.Buffer
        pred := func(b bool, s string) {
                if b {
                        if buf.Len() > 0 {
                                buf.WriteString(", ")
                        }
                        buf.WriteString(s)
                }
        }

        pred(tv.IsVoid(), "void")
        pred(tv.IsType(), "type")
        pred(tv.IsBuiltin(), "builtin")
        pred(tv.IsValue() && tv.Value != nil, "const")
        pred(tv.IsValue() && tv.Value == nil, "value")
        pred(tv.IsNil(), "nil")
        pred(tv.Addressable(), "addressable")
        pred(tv.Assignable(), "assignable")
        pred(tv.HasOk(), "hasOk")

        if buf.Len() == 0 {
                return "invalid"
        }
        return buf.String()
}

func TestPredicatesInfo(t *testing.T) {
        testenv.MustHaveGoBuild(t)

        var tests = []struct {
                src  string
                expr string
                pred string
        }{
                // void
                {`package n0; func f() { f() }`, `f()`, `void`},

                // types
                {`package t0; type _ int`, `int`, `type`},
                {`package t1; type _ []int`, `[]int`, `type`},
                {`package t2; type _ func()`, `func()`, `type`},

                // built-ins
                {`package b0; var _ = len("")`, `len`, `builtin`},
                {`package b1; var _ = (len)("")`, `(len)`, `builtin`},

                // constants
                {`package c0; var _ = 42`, `42`, `const`},
                {`package c1; var _ = "foo" + "bar"`, `"foo" + "bar"`, `const`},
                {`package c2; const (i = 1i; _ = i)`, `i`, `const`},

                // values
                {`package v0; var (a, b int; _ = a + b)`, `a + b`, `value`},
                {`package v1; var _ = &[]int{1}`, `([]int literal)`, `value`},
                {`package v2; var _ = func(){}`, `(func() literal)`, `value`},
                {`package v4; func f() { _ = f }`, `f`, `value`},
                {`package v3; var _ *int = nil`, `nil`, `value, nil`},
                {`package v3; var _ *int = (nil)`, `(nil)`, `value, nil`},

                // addressable (and thus assignable) operands
                {`package a0; var (x int; _ = x)`, `x`, `value, addressable, assignable`},
                {`package a1; var (p *int; _ = *p)`, `*p`, `value, addressable, assignable`},
                {`package a2; var (s []int; _ = s[0])`, `s[0]`, `value, addressable, assignable`},
                {`package a3; var (s struct{f int}; _ = s.f)`, `s.f`, `value, addressable, assignable`},
                {`package a4; var (a [10]int; _ = a[0])`, `a[0]`, `value, addressable, assignable`},
                {`package a5; func _(x int) { _ = x }`, `x`, `value, addressable, assignable`},
                {`package a6; func _()(x int) { _ = x; return }`, `x`, `value, addressable, assignable`},
                {`package a7; type T int; func (x T) _() { _ = x }`, `x`, `value, addressable, assignable`},
                // composite literals are not addressable

                // assignable but not addressable values
                {`package s0; var (m map[int]int; _ = m[0])`, `m[0]`, `value, assignable, hasOk`},
                {`package s1; var (m map[int]int; _, _ = m[0])`, `m[0]`, `value, assignable, hasOk`},

                // hasOk expressions
                {`package k0; var (ch chan int; _ = <-ch)`, `<-ch`, `value, hasOk`},
                {`package k1; var (ch chan int; _, _ = <-ch)`, `<-ch`, `value, hasOk`},

                // missing entries
                // - package names are collected in the Uses map
                // - identifiers being declared are collected in the Defs map
                {`package m0; import "os"; func _() { _ = os.Stdout }`, `os`, `<missing>`},
                {`package m1; import p "os"; func _() { _ = p.Stdout }`, `p`, `<missing>`},
                {`package m2; const c = 0`, `c`, `<missing>`},
                {`package m3; type T int`, `T`, `<missing>`},
                {`package m4; var v int`, `v`, `<missing>`},
                {`package m5; func f() {}`, `f`, `<missing>`},
                {`package m6; func _(x int) {}`, `x`, `<missing>`},
                {`package m6; func _()(x int) { return }`, `x`, `<missing>`},
                {`package m6; type T int; func (x T) _() {}`, `x`, `<missing>`},
        }

        for _, test := range tests {
                info := Info{Types: make(map[ast.Expr]TypeAndValue)}
                name := mustTypecheck(t, "PredicatesInfo", test.src, &info)

                // look for expression predicates
                got := "<missing>"
                for e, tv := range info.Types {
                        //println(name, ExprString(e))
                        if ExprString(e) == test.expr {
                                got = predString(tv)
                                break
                        }
                }

                if got != test.pred {
                        t.Errorf("package %s: got %s; want %s", name, got, test.pred)
                }
        }
}

func TestScopesInfo(t *testing.T) {
        testenv.MustHaveGoBuild(t)

        var tests = []struct {
                src    string
                scopes []string // list of scope descriptors of the form kind:varlist
        }{
                {`package p0`, []string{
                        "file:",
                }},
                {`package p1; import ( "fmt"; m "math"; _ "os" ); var ( _ = fmt.Println; _ = m.Pi )`, []string{
                        "file:fmt m",
                }},
                {`package p2; func _() {}`, []string{
                        "file:", "func:",
                }},
                {`package p3; func _(x, y int) {}`, []string{
                        "file:", "func:x y",
                }},
                {`package p4; func _(x, y int) { x, z := 1, 2; _ = z }`, []string{
                        "file:", "func:x y z", // redeclaration of x
                }},
                {`package p5; func _(x, y int) (u, _ int) { return }`, []string{
                        "file:", "func:u x y",
                }},
                {`package p6; func _() { { var x int; _ = x } }`, []string{
                        "file:", "func:", "block:x",
                }},
                {`package p7; func _() { if true {} }`, []string{
                        "file:", "func:", "if:", "block:",
                }},
                {`package p8; func _() { if x := 0; x < 0 { y := x; _ = y } }`, []string{
                        "file:", "func:", "if:x", "block:y",
                }},
                {`package p9; func _() { switch x := 0; x {} }`, []string{
                        "file:", "func:", "switch:x",
                }},
                {`package p10; func _() { switch x := 0; x { case 1: y := x; _ = y; default: }}`, []string{
                        "file:", "func:", "switch:x", "case:y", "case:",
                }},
                {`package p11; func _(t interface{}) { switch t.(type) {} }`, []string{
                        "file:", "func:t", "type switch:",
                }},
                {`package p12; func _(t interface{}) { switch t := t; t.(type) {} }`, []string{
                        "file:", "func:t", "type switch:t",
                }},
                {`package p13; func _(t interface{}) { switch x := t.(type) { case int: _ = x } }`, []string{
                        "file:", "func:t", "type switch:", "case:x", // x implicitly declared
                }},
                {`package p14; func _() { select{} }`, []string{
                        "file:", "func:",
                }},
                {`package p15; func _(c chan int) { select{ case <-c: } }`, []string{
                        "file:", "func:c", "comm:",
                }},
                {`package p16; func _(c chan int) { select{ case i := <-c: x := i; _ = x} }`, []string{
                        "file:", "func:c", "comm:i x",
                }},
                {`package p17; func _() { for{} }`, []string{
                        "file:", "func:", "for:", "block:",
                }},
                {`package p18; func _(n int) { for i := 0; i < n; i++ { _ = i } }`, []string{
                        "file:", "func:n", "for:i", "block:",
                }},
                {`package p19; func _(a []int) { for i := range a { _ = i} }`, []string{
                        "file:", "func:a", "range:i", "block:",
                }},
                {`package p20; var s int; func _(a []int) { for i, x := range a { s += x; _ = i } }`, []string{
                        "file:", "func:a", "range:i x", "block:",
                }},
        }

        for _, test := range tests {
                info := Info{Scopes: make(map[ast.Node]*Scope)}
                name := mustTypecheck(t, "ScopesInfo", test.src, &info)

                // number of scopes must match
                if len(info.Scopes) != len(test.scopes) {
                        t.Errorf("package %s: got %d scopes; want %d", name, len(info.Scopes), len(test.scopes))
                }

                // scope descriptions must match
                for node, scope := range info.Scopes {
                        kind := "<unknown node kind>"
                        switch node.(type) {
                        case *ast.File:
                                kind = "file"
                        case *ast.FuncType:
                                kind = "func"
                        case *ast.BlockStmt:
                                kind = "block"
                        case *ast.IfStmt:
                                kind = "if"
                        case *ast.SwitchStmt:
                                kind = "switch"
                        case *ast.TypeSwitchStmt:
                                kind = "type switch"
                        case *ast.CaseClause:
                                kind = "case"
                        case *ast.CommClause:
                                kind = "comm"
                        case *ast.ForStmt:
                                kind = "for"
                        case *ast.RangeStmt:
                                kind = "range"
                        }

                        // look for matching scope description
                        desc := kind + ":" + strings.Join(scope.Names(), " ")
                        found := false
                        for _, d := range test.scopes {
                                if desc == d {
                                        found = true
                                        break
                                }
                        }
                        if !found {
                                t.Errorf("package %s: no matching scope found for %s", name, desc)
                        }
                }
        }
}

func TestInitOrderInfo(t *testing.T) {
        var tests = []struct {
                src   string
                inits []string
        }{
                {`package p0; var (x = 1; y = x)`, []string{
                        "x = 1", "y = x",
                }},
                {`package p1; var (a = 1; b = 2; c = 3)`, []string{
                        "a = 1", "b = 2", "c = 3",
                }},
                {`package p2; var (a, b, c = 1, 2, 3)`, []string{
                        "a = 1", "b = 2", "c = 3",
                }},
                {`package p3; var _ = f(); func f() int { return 1 }`, []string{
                        "_ = f()", // blank var
                }},
                {`package p4; var (a = 0; x = y; y = z; z = 0)`, []string{
                        "a = 0", "z = 0", "y = z", "x = y",
                }},
                {`package p5; var (a, _ = m[0]; m map[int]string)`, []string{
                        "a, _ = m[0]", // blank var
                }},
                {`package p6; var a, b = f(); func f() (_, _ int) { return z, z }; var z = 0`, []string{
                        "z = 0", "a, b = f()",
                }},
                {`package p7; var (a = func() int { return b }(); b = 1)`, []string{
                        "b = 1", "a = (func() int literal)()",
                }},
                {`package p8; var (a, b = func() (_, _ int) { return c, c }(); c = 1)`, []string{
                        "c = 1", "a, b = (func() (_, _ int) literal)()",
                }},
                {`package p9; type T struct{}; func (T) m() int { _ = y; return 0 }; var x, y = T.m, 1`, []string{
                        "y = 1", "x = T.m",
                }},
                {`package p10; var (d = c + b; a = 0; b = 0; c = 0)`, []string{
                        "a = 0", "b = 0", "c = 0", "d = c + b",
                }},
                {`package p11; var (a = e + c; b = d + c; c = 0; d = 0; e = 0)`, []string{
                        "c = 0", "d = 0", "b = d + c", "e = 0", "a = e + c",
                }},
                // emit an initializer for n:1 initializations only once (not for each node
                // on the lhs which may appear in different order in the dependency graph)
                {`package p12; var (a = x; b = 0; x, y = m[0]; m map[int]int)`, []string{
                        "b = 0", "x, y = m[0]", "a = x",
                }},
                // test case from spec section on package initialization
                {`package p12

                var (
                        a = c + b
                        b = f()
                        c = f()
                        d = 3
                )

                func f() int {
                        d++
                        return d
                }`, []string{
                        "d = 3", "b = f()", "c = f()", "a = c + b",
                }},
                // test case for issue 7131
                {`package main

                var counter int
                func next() int { counter++; return counter }

                var _ = makeOrder()
                func makeOrder() []int { return []int{f, b, d, e, c, a} }

                var a       = next()
                var b, c    = next(), next()
                var d, e, f = next(), next(), next()
                `, []string{
                        "a = next()", "b = next()", "c = next()", "d = next()", "e = next()", "f = next()", "_ = makeOrder()",
                }},
                // test case for issue 10709
                {`package p13

                var (
                    v = t.m()
                    t = makeT(0)
                )

                type T struct{}

                func (T) m() int { return 0 }

                func makeT(n int) T {
                    if n > 0 {
                        return makeT(n-1)
                    }
                    return T{}
                }`, []string{
                        "t = makeT(0)", "v = t.m()",
                }},
                // test case for issue 10709: same as test before, but variable decls swapped
                {`package p14

                var (
                    t = makeT(0)
                    v = t.m()
                )

                type T struct{}

                func (T) m() int { return 0 }

                func makeT(n int) T {
                    if n > 0 {
                        return makeT(n-1)
                    }
                    return T{}
                }`, []string{
                        "t = makeT(0)", "v = t.m()",
                }},
                // another candidate possibly causing problems with issue 10709
                {`package p15

                var y1 = f1()

                func f1() int { return g1() }
                func g1() int { f1(); return x1 }

                var x1 = 0

                var y2 = f2()

                func f2() int { return g2() }
                func g2() int { return x2 }

                var x2 = 0`, []string{
                        "x1 = 0", "y1 = f1()", "x2 = 0", "y2 = f2()",
                }},
        }

        for _, test := range tests {
                info := Info{}
                name := mustTypecheck(t, "InitOrderInfo", test.src, &info)

                // number of initializers must match
                if len(info.InitOrder) != len(test.inits) {
                        t.Errorf("package %s: got %d initializers; want %d", name, len(info.InitOrder), len(test.inits))
                        continue
                }

                // initializers must match
                for i, want := range test.inits {
                        got := info.InitOrder[i].String()
                        if got != want {
                                t.Errorf("package %s, init %d: got %s; want %s", name, i, got, want)
                                continue
                        }
                }
        }
}

func TestMultiFileInitOrder(t *testing.T) {
        fset := token.NewFileSet()
        mustParse := func(src string) *ast.File {
                f, err := parser.ParseFile(fset, "main", src, 0)
                if err != nil {
                        t.Fatal(err)
                }
                return f
        }

        fileA := mustParse(`package main; var a = 1`)
        fileB := mustParse(`package main; var b = 2`)

        // The initialization order must not depend on the parse
        // order of the files, only on the presentation order to
        // the type-checker.
        for _, test := range []struct {
                files []*ast.File
                want  string
        }{
                {[]*ast.File{fileA, fileB}, "[a = 1 b = 2]"},
                {[]*ast.File{fileB, fileA}, "[b = 2 a = 1]"},
        } {
                var info Info
                if _, err := new(Config).Check("main", fset, test.files, &info); err != nil {
                        t.Fatal(err)
                }
                if got := fmt.Sprint(info.InitOrder); got != test.want {
                        t.Fatalf("got %s; want %s", got, test.want)
                }
        }
}

func TestFiles(t *testing.T) {
        var sources = []string{
                "package p; type T struct{}; func (T) m1() {}",
                "package p; func (T) m2() {}; var x interface{ m1(); m2() } = T{}",
                "package p; func (T) m3() {}; var y interface{ m1(); m2(); m3() } = T{}",
                "package p",
        }

        var conf Config
        fset := token.NewFileSet()
        pkg := NewPackage("p", "p")
        var info Info
        check := NewChecker(&conf, fset, pkg, &info)

        for i, src := range sources {
                filename := fmt.Sprintf("sources%d", i)
                f, err := parser.ParseFile(fset, filename, src, 0)
                if err != nil {
                        t.Fatal(err)
                }
                if err := check.Files([]*ast.File{f}); err != nil {
                        t.Error(err)
                }
        }

        // check InitOrder is [x y]
        var vars []string
        for _, init := range info.InitOrder {
                for _, v := range init.Lhs {
                        vars = append(vars, v.Name())
                }
        }
        if got, want := fmt.Sprint(vars), "[x y]"; got != want {
                t.Errorf("InitOrder == %s, want %s", got, want)
        }
}

type testImporter map[string]*Package

func (m testImporter) Import(path string) (*Package, error) {
        if pkg := m[path]; pkg != nil {
                return pkg, nil
        }
        return nil, fmt.Errorf("package %q not found", path)
}

func TestSelection(t *testing.T) {
        selections := make(map[*ast.SelectorExpr]*Selection)

        fset := token.NewFileSet()
        imports := make(testImporter)
        conf := Config{Importer: imports}
        makePkg := func(path, src string) {
                f, err := parser.ParseFile(fset, path+".go", src, 0)
                if err != nil {
                        t.Fatal(err)
                }
                pkg, err := conf.Check(path, fset, []*ast.File{f}, &Info{Selections: selections})
                if err != nil {
                        t.Fatal(err)
                }
                imports[path] = pkg
        }

        const libSrc = `
package lib
type T float64
const C T = 3
var V T
func F() {}
func (T) M() {}
`
        const mainSrc = `
package main
import "lib"

type A struct {
        *B
        C
}

type B struct {
        b int
}

func (B) f(int)

type C struct {
        c int
}

func (C) g()
func (*C) h()

func main() {
        // qualified identifiers
        var _ lib.T
        _ = lib.C
        _ = lib.F
        _ = lib.V
        _ = lib.T.M

        // fields
        _ = A{}.B
        _ = new(A).B

        _ = A{}.C
        _ = new(A).C

        _ = A{}.b
        _ = new(A).b

        _ = A{}.c
        _ = new(A).c

        // methods
        _ = A{}.f
        _ = new(A).f
        _ = A{}.g
        _ = new(A).g
        _ = new(A).h

        _ = B{}.f
        _ = new(B).f

        _ = C{}.g
        _ = new(C).g
        _ = new(C).h

        // method expressions
        _ = A.f
        _ = (*A).f
        _ = B.f
        _ = (*B).f
}`

        wantOut := map[string][2]string{
                "lib.T.M": {"method expr (lib.T) M(lib.T)", ".[0]"},

                "A{}.B":    {"field (main.A) B *main.B", ".[0]"},
                "new(A).B": {"field (*main.A) B *main.B", "->[0]"},
                "A{}.C":    {"field (main.A) C main.C", ".[1]"},
                "new(A).C": {"field (*main.A) C main.C", "->[1]"},
                "A{}.b":    {"field (main.A) b int", "->[0 0]"},
                "new(A).b": {"field (*main.A) b int", "->[0 0]"},
                "A{}.c":    {"field (main.A) c int", ".[1 0]"},
                "new(A).c": {"field (*main.A) c int", "->[1 0]"},

                "A{}.f":    {"method (main.A) f(int)", "->[0 0]"},
                "new(A).f": {"method (*main.A) f(int)", "->[0 0]"},
                "A{}.g":    {"method (main.A) g()", ".[1 0]"},
                "new(A).g": {"method (*main.A) g()", "->[1 0]"},
                "new(A).h": {"method (*main.A) h()", "->[1 1]"}, // TODO(gri) should this report .[1 1] ?
                "B{}.f":    {"method (main.B) f(int)", ".[0]"},
                "new(B).f": {"method (*main.B) f(int)", "->[0]"},
                "C{}.g":    {"method (main.C) g()", ".[0]"},
                "new(C).g": {"method (*main.C) g()", "->[0]"},
                "new(C).h": {"method (*main.C) h()", "->[1]"}, // TODO(gri) should this report .[1] ?

                "A.f":    {"method expr (main.A) f(main.A, int)", "->[0 0]"},
                "(*A).f": {"method expr (*main.A) f(*main.A, int)", "->[0 0]"},
                "B.f":    {"method expr (main.B) f(main.B, int)", ".[0]"},
                "(*B).f": {"method expr (*main.B) f(*main.B, int)", "->[0]"},
        }

        makePkg("lib", libSrc)
        makePkg("main", mainSrc)

        for e, sel := range selections {
                _ = sel.String() // assertion: must not panic

                start := fset.Position(e.Pos()).Offset
                end := fset.Position(e.End()).Offset
                syntax := mainSrc[start:end] // (all SelectorExprs are in main, not lib)

                direct := "."
                if sel.Indirect() {
                        direct = "->"
                }
                got := [2]string{
                        sel.String(),
                        fmt.Sprintf("%s%v", direct, sel.Index()),
                }
                want := wantOut[syntax]
                if want != got {
                        t.Errorf("%s: got %q; want %q", syntax, got, want)
                }
                delete(wantOut, syntax)

                // We must explicitly assert properties of the
                // Signature's receiver since it doesn't participate
                // in Identical() or String().
                sig, _ := sel.Type().(*Signature)
                if sel.Kind() == MethodVal {
                        got := sig.Recv().Type()
                        want := sel.Recv()
                        if !Identical(got, want) {
                                t.Errorf("%s: Recv() = %s, want %s", syntax, got, want)
                        }
                } else if sig != nil && sig.Recv() != nil {
                        t.Errorf("%s: signature has receiver %s", sig, sig.Recv().Type())
                }
        }
        // Assert that all wantOut entries were used exactly once.
        for syntax := range wantOut {
                t.Errorf("no ast.Selection found with syntax %q", syntax)
        }
}

func TestIssue8518(t *testing.T) {
        fset := token.NewFileSet()
        imports := make(testImporter)
        conf := Config{
                Error:    func(err error) { t.Log(err) }, // don't exit after first error
                Importer: imports,
        }
        makePkg := func(path, src string) {
                f, err := parser.ParseFile(fset, path, src, 0)
                if err != nil {
                        t.Fatal(err)
                }
                pkg, _ := conf.Check(path, fset, []*ast.File{f}, nil) // errors logged via conf.Error
                imports[path] = pkg
        }

        const libSrc = `
package a
import "missing"
const C1 = foo
const C2 = missing.C
`

        const mainSrc = `
package main
import "a"
var _ = a.C1
var _ = a.C2
`

        makePkg("a", libSrc)
        makePkg("main", mainSrc) // don't crash when type-checking this package
}

func TestLookupFieldOrMethod(t *testing.T) {
        t.Skip("skipping for gccgo--no importer")
        // Test cases assume a lookup of the form a.f or x.f, where a stands for an
        // addressable value, and x for a non-addressable value (even though a variable
        // for ease of test case writing).
        var tests = []struct {
                src      string
                found    bool
                index    []int
                indirect bool
        }{
                // field lookups
                {"var x T; type T struct{}", false, nil, false},
                {"var x T; type T struct{ f int }", true, []int{0}, false},
                {"var x T; type T struct{ a, b, f, c int }", true, []int{2}, false},

                // method lookups
                {"var a T; type T struct{}; func (T) f() {}", true, []int{0}, false},
                {"var a *T; type T struct{}; func (T) f() {}", true, []int{0}, true},
                {"var a T; type T struct{}; func (*T) f() {}", true, []int{0}, false},
                {"var a *T; type T struct{}; func (*T) f() {}", true, []int{0}, true}, // TODO(gri) should this report indirect = false?

                // collisions
                {"type ( E1 struct{ f int }; E2 struct{ f int }; x struct{ E1; *E2 })", false, []int{1, 0}, false},
                {"type ( E1 struct{ f int }; E2 struct{}; x struct{ E1; *E2 }); func (E2) f() {}", false, []int{1, 0}, false},

                // outside methodset
                // (*T).f method exists, but value of type T is not addressable
                {"var x T; type T struct{}; func (*T) f() {}", false, nil, true},
        }

        for _, test := range tests {
                pkg, err := pkgFor("test", "package p;"+test.src, nil)
                if err != nil {
                        t.Errorf("%s: incorrect test case: %s", test.src, err)
                        continue
                }

                obj := pkg.Scope().Lookup("a")
                if obj == nil {
                        if obj = pkg.Scope().Lookup("x"); obj == nil {
                                t.Errorf("%s: incorrect test case - no object a or x", test.src)
                                continue
                        }
                }

                f, index, indirect := LookupFieldOrMethod(obj.Type(), obj.Name() == "a", pkg, "f")
                if (f != nil) != test.found {
                        if f == nil {
                                t.Errorf("%s: got no object; want one", test.src)
                        } else {
                                t.Errorf("%s: got object = %v; want none", test.src, f)
                        }
                }
                if !sameSlice(index, test.index) {
                        t.Errorf("%s: got index = %v; want %v", test.src, index, test.index)
                }
                if indirect != test.indirect {
                        t.Errorf("%s: got indirect = %v; want %v", test.src, indirect, test.indirect)
                }
        }
}

func sameSlice(a, b []int) bool {
        if len(a) != len(b) {
                return false
        }
        for i, x := range a {
                if x != b[i] {
                        return false
                }
        }
        return true
}

// TestScopeLookupParent ensures that (*Scope).LookupParent returns
// the correct result at various positions with the source.
func TestScopeLookupParent(t *testing.T) {
        fset := token.NewFileSet()
        imports := make(testImporter)
        conf := Config{Importer: imports}
        mustParse := func(src string) *ast.File {
                f, err := parser.ParseFile(fset, "dummy.go", src, parser.ParseComments)
                if err != nil {
                        t.Fatal(err)
                }
                return f
        }
        var info Info
        makePkg := func(path string, files ...*ast.File) {
                var err error
                imports[path], err = conf.Check(path, fset, files, &info)
                if err != nil {
                        t.Fatal(err)
                }
        }

        makePkg("lib", mustParse("package lib; var X int"))
        // Each /*name=kind:line*/ comment makes the test look up the
        // name at that point and checks that it resolves to a decl of
        // the specified kind and line number.  "undef" means undefined.
        mainSrc := `
/*lib=pkgname:5*/ /*X=var:1*/ /*Pi=const:8*/ /*T=typename:9*/ /*Y=var:10*/ /*F=func:12*/
package main

import "lib"
import . "lib"

const Pi = 3.1415
type T struct{}
var Y, _ = lib.X, X

func F(){
        const pi, e = 3.1415, /*pi=undef*/ 2.71828 /*pi=const:13*/ /*e=const:13*/
        type /*t=undef*/ t /*t=typename:14*/ *t
        print(Y) /*Y=var:10*/
        x, Y := Y, /*x=undef*/ /*Y=var:10*/ Pi /*x=var:16*/ /*Y=var:16*/ ; _ = x; _ = Y
        var F = /*F=func:12*/ F /*F=var:17*/ ; _ = F

        var a []int
        for i, x := range /*i=undef*/ /*x=var:16*/ a /*i=var:20*/ /*x=var:20*/ { _ = i; _ = x }

        var i interface{}
        switch y := i.(type) { /*y=undef*/
        case /*y=undef*/ int /*y=var:23*/ :
        case float32, /*y=undef*/ float64 /*y=var:23*/ :
        default /*y=var:23*/:
                println(y)
        }
        /*y=undef*/

        switch int := i.(type) {
        case /*int=typename:0*/ int /*int=var:31*/ :
                println(int)
        default /*int=var:31*/ :
        }
}
/*main=undef*/
`

        info.Uses = make(map[*ast.Ident]Object)
        f := mustParse(mainSrc)
        makePkg("main", f)
        mainScope := imports["main"].Scope()
        rx := regexp.MustCompile(`^/\*(\w*)=([\w:]*)\*/$`)
        for _, group := range f.Comments {
                for _, comment := range group.List {
                        // Parse the assertion in the comment.
                        m := rx.FindStringSubmatch(comment.Text)
                        if m == nil {
                                t.Errorf("%s: bad comment: %s",
                                        fset.Position(comment.Pos()), comment.Text)
                                continue
                        }
                        name, want := m[1], m[2]

                        // Look up the name in the innermost enclosing scope.
                        inner := mainScope.Innermost(comment.Pos())
                        if inner == nil {
                                t.Errorf("%s: at %s: can't find innermost scope",
                                        fset.Position(comment.Pos()), comment.Text)
                                continue
                        }
                        got := "undef"
                        if _, obj := inner.LookupParent(name, comment.Pos()); obj != nil {
                                kind := strings.ToLower(strings.TrimPrefix(reflect.TypeOf(obj).String(), "*types."))
                                got = fmt.Sprintf("%s:%d", kind, fset.Position(obj.Pos()).Line)
                        }
                        if got != want {
                                t.Errorf("%s: at %s: %s resolved to %s, want %s",
                                        fset.Position(comment.Pos()), comment.Text, name, got, want)
                        }
                }
        }

        // Check that for each referring identifier,
        // a lookup of its name on the innermost
        // enclosing scope returns the correct object.

        for id, wantObj := range info.Uses {
                inner := mainScope.Innermost(id.Pos())
                if inner == nil {
                        t.Errorf("%s: can't find innermost scope enclosing %q",
                                fset.Position(id.Pos()), id.Name)
                        continue
                }

                // Exclude selectors and qualified identifiers---lexical
                // refs only.  (Ideally, we'd see if the AST parent is a
                // SelectorExpr, but that requires PathEnclosingInterval
                // from golang.org/x/tools/go/ast/astutil.)
                if id.Name == "X" {
                        continue
                }

                _, gotObj := inner.LookupParent(id.Name, id.Pos())
                if gotObj != wantObj {
                        t.Errorf("%s: got %v, want %v",
                                fset.Position(id.Pos()), gotObj, wantObj)
                        continue
                }
        }
}

func TestIdentical_issue15173(t *testing.T) {
        // Identical should allow nil arguments and be symmetric.
        for _, test := range []struct {
                x, y Type
                want bool
        }{
                {Typ[Int], Typ[Int], true},
                {Typ[Int], nil, false},
                {nil, Typ[Int], false},
                {nil, nil, true},
        } {
                if got := Identical(test.x, test.y); got != test.want {
                        t.Errorf("Identical(%v, %v) = %t", test.x, test.y, got)
                }
        }
}

func TestIssue15305(t *testing.T) {
        const src = "package p; func f() int16; var _ = f(undef)"
        fset := token.NewFileSet()
        f, err := parser.ParseFile(fset, "issue15305.go", src, 0)
        if err != nil {
                t.Fatal(err)
        }
        conf := Config{
                Error: func(err error) {}, // allow errors
        }
        info := &Info{
                Types: make(map[ast.Expr]TypeAndValue),
        }
        conf.Check("p", fset, []*ast.File{f}, info) // ignore result
        for e, tv := range info.Types {
                if _, ok := e.(*ast.CallExpr); ok {
                        if tv.Type != Typ[Int16] {
                                t.Errorf("CallExpr has type %v, want int16", tv.Type)
                        }
                        return
                }
        }
        t.Errorf("CallExpr has no type")
}

// TestCompositeLitTypes verifies that Info.Types registers the correct
// types for composite literal expressions and composite literal type
// expressions.
func TestCompositeLitTypes(t *testing.T) {
        for _, test := range []struct {
                lit, typ string
        }{
                {`[16]byte{}`, `[16]byte`},
                {`[...]byte{}`, `[0]byte`},                // test for issue #14092
                {`[...]int{1, 2, 3}`, `[3]int`},           // test for issue #14092
                {`[...]int{90: 0, 98: 1, 2}`, `[100]int`}, // test for issue #14092
                {`[]int{}`, `[]int`},
                {`map[string]bool{"foo": true}`, `map[string]bool`},
                {`struct{}{}`, `struct{}`},
                {`struct{x, y int; z complex128}{}`, `struct{x int; y int; z complex128}`},
        } {
                fset := token.NewFileSet()
                f, err := parser.ParseFile(fset, test.lit, "package p; var _ = "+test.lit, 0)
                if err != nil {
                        t.Fatalf("%s: %v", test.lit, err)
                }

                info := &Info{
                        Types: make(map[ast.Expr]TypeAndValue),
                }
                if _, err = new(Config).Check("p", fset, []*ast.File{f}, info); err != nil {
                        t.Fatalf("%s: %v", test.lit, err)
                }

                cmptype := func(x ast.Expr, want string) {
                        tv, ok := info.Types[x]
                        if !ok {
                                t.Errorf("%s: no Types entry found", test.lit)
                                return
                        }
                        if tv.Type == nil {
                                t.Errorf("%s: type is nil", test.lit)
                                return
                        }
                        if got := tv.Type.String(); got != want {
                                t.Errorf("%s: got %v, want %s", test.lit, got, want)
                        }
                }

                // test type of composite literal expression
                rhs := f.Decls[0].(*ast.GenDecl).Specs[0].(*ast.ValueSpec).Values[0]
                cmptype(rhs, test.typ)

                // test type of composite literal type expression
                cmptype(rhs.(*ast.CompositeLit).Type, test.typ)
        }
}

// TestObjectParents verifies that objects have parent scopes or not
// as specified by the Object interface.
func TestObjectParents(t *testing.T) {
        const src = `
package p

const C = 0

type T1 struct {
        a, b int
        T2
}

type T2 interface {
        im1()
        im2()
}

func (T1) m1() {}
func (*T1) m2() {}

func f(x int) { y := x; print(y) }
`

        fset := token.NewFileSet()
        f, err := parser.ParseFile(fset, "src", src, 0)
        if err != nil {
                t.Fatal(err)
        }

        info := &Info{
                Defs: make(map[*ast.Ident]Object),
        }
        if _, err = new(Config).Check("p", fset, []*ast.File{f}, info); err != nil {
                t.Fatal(err)
        }

        for ident, obj := range info.Defs {
                if obj == nil {
                        // only package names and implicit vars have a nil object
                        // (in this test we only need to handle the package name)
                        if ident.Name != "p" {
                                t.Errorf("%v has nil object", ident)
                        }
                        continue
                }

                // struct fields, type-associated and interface methods
                // have no parent scope
                wantParent := true
                switch obj := obj.(type) {
                case *Var:
                        if obj.IsField() {
                                wantParent = false
                        }
                case *Func:
                        if obj.Type().(*Signature).Recv() != nil { // method
                                wantParent = false
                        }
                }

                gotParent := obj.Parent() != nil
                switch {
                case gotParent && !wantParent:
                        t.Errorf("%v: want no parent, got %s", ident, obj.Parent())
                case !gotParent && wantParent:
                        t.Errorf("%v: no parent found", ident)
                }
        }
}

// TestFailedImport tests that we don't get follow-on errors
// elsewhere in a package due to failing to import a package.
func TestFailedImport(t *testing.T) {
        testenv.MustHaveGoBuild(t)

        const src = `
package p

import "foo" // should only see an error here

const c = foo.C
type T = foo.T
var v T = c
func f(x T) T { return foo.F(x) }
`
        fset := token.NewFileSet()
        f, err := parser.ParseFile(fset, "src", src, 0)
        if err != nil {
                t.Fatal(err)
        }
        files := []*ast.File{f}

        // type-check using all possible importers
        for _, compiler := range []string{"gc", "gccgo", "source"} {
                errcount := 0
                conf := Config{
                        Error: func(err error) {
                                // we should only see the import error
                                if errcount > 0 || !strings.Contains(err.Error(), "could not import foo") {
                                        t.Errorf("for %s importer, got unexpected error: %v", compiler, err)
                                }
                                errcount++
                        },
                        Importer: importer.For(compiler, nil),
                }

                info := &Info{
                        Uses: make(map[*ast.Ident]Object),
                }
                pkg, _ := conf.Check("p", fset, files, info)
                if pkg == nil {
                        t.Errorf("for %s importer, type-checking failed to return a package", compiler)
                        continue
                }

                imports := pkg.Imports()
                if len(imports) != 1 {
                        t.Errorf("for %s importer, got %d imports, want 1", compiler, len(imports))
                        continue
                }
                imp := imports[0]
                if imp.Name() != "foo" {
                        t.Errorf(`for %s importer, got %q, want "foo"`, compiler, imp.Name())
                        continue
                }

                // verify that all uses of foo refer to the imported package foo (imp)
                for ident, obj := range info.Uses {
                        if ident.Name == "foo" {
                                if obj, ok := obj.(*PkgName); ok {
                                        if obj.Imported() != imp {
                                                t.Errorf("%s resolved to %v; want %v", ident, obj.Imported(), imp)
                                        }
                                } else {
                                        t.Errorf("%s resolved to %v; want package name", ident, obj)
                                }
                        }
                }
        }
}