//processDefs going through all definitions in the next order:
// - collect info about all interfaces
// - process everuthing except vars and functions to collect all structs prior vars and functions
// - process vars and functions
func processDefs(info *types.Info, ctx *getDefinitionsContext) {
	//Collect all interfaces
	for ident, obj := range info.Defs {
		if !isValidObject(obj, ident, ctx) || !types.IsInterface(obj.Type()) {
			continue
		}
		addInterface(obj, ident, ctx)
	}

	logInterfaces(ctx)

	//Collect everything except vars and functions
	for ident, obj := range info.Defs {
		if !isValidObject(obj, ident, ctx) {
			continue
		}
		var def *Definition
		if !isVar(obj) && !isFunc(obj) && !types.IsInterface(obj.Type()) {
			def = createDef(obj, ident, ctx, false)
		}
		updateGetDefinitionsContext(ctx, def, ident, obj)
	}

	for _, v := range ctx.vars {
		createDef(v.obj, v.ident, ctx, false)
	}

	for _, v := range ctx.funcs {
		createDef(v.obj, v.ident, ctx, false)
	}
}

// IntuitiveMethodSet returns the intuitive method set of a type T,
// which is the set of methods you can call on an addressable value of
// that type.
//
// The result always contains MethodSet(T), and is exactly MethodSet(T)
// for interface types and for pointer-to-concrete types.
// For all other concrete types T, the result additionally
// contains each method belonging to *T if there is no identically
// named method on T itself.
//
// This corresponds to user intuition about method sets;
// this function is intended only for user interfaces.
//
// The order of the result is as for types.MethodSet(T).
//
func IntuitiveMethodSet(T types.Type, msets *MethodSetCache) []*types.Selection {
	isPointerToConcrete := func(T types.Type) bool {
		ptr, ok := T.(*types.Pointer)
		return ok && !types.IsInterface(ptr.Elem())
	}

	var result []*types.Selection
	mset := msets.MethodSet(T)
	if types.IsInterface(T) || isPointerToConcrete(T) {
		for i, n := 0, mset.Len(); i < n; i++ {
			result = append(result, mset.At(i))
		}
	} else {
		// T is some other concrete type.
		// Report methods of T and *T, preferring those of T.
		pmset := msets.MethodSet(types.NewPointer(T))
		for i, n := 0, pmset.Len(); i < n; i++ {
			meth := pmset.At(i)
			if m := mset.Lookup(meth.Obj().Pkg(), meth.Obj().Name()); m != nil {
				meth = m
			}
			result = append(result, meth)
		}

	}
	return result
}

func createDef(obj types.Object, ident *ast.Ident, ctx *getDefinitionsContext, isType bool) *Definition {
	fullName := getFullName(obj, ctx, isType)

	if def, ok := ctx.defs[fullName]; ok {
		return def
	}

	def := new(Definition)
	def.Name = fullName
	def.Pkg = obj.Pkg()
	def.IsExported = obj.Exported()
	def.TypeOf = reflect.TypeOf(obj)
	def.SimpleName = obj.Name()
	def.Usages = make([]*Usage, 0)
	def.InterfacesDefs = make([]*Definition, 0)

	if ident != nil {
		position := ctx.fset.Position(ident.Pos())
		def.File = position.Filename
		def.Line = position.Line
		def.Offset = position.Offset
		def.Col = position.Column
	}

	if !types.IsInterface(obj.Type()) {
		fillInterfaces(def, obj, ctx)
	}

	ctx.defs[def.Name] = def
	logDefinition(def, obj, ident, ctx)

	return def
}

//processTypes is only filling interfaces from function signatures.
func processTypes(info *types.Info, ctx *context) {
	for _, t := range info.Types {
		logType(t)

		if t.Type != nil {
			switch t.Type.(type) {
			//If it's a function signature then extracting
			//all params and trying to find interfaces.
			//We are doing this to find usages of interfaces
			//cause methods of the interfaces could be called
			// inside internal functions
			case *types.Signature:
				s := t.Type.(*types.Signature)
				if tuple := s.Params(); tuple != nil {
					for i := 0; i < tuple.Len(); i++ {
						v := tuple.At(i)
						if types.IsInterface(v.Type()) {
							addInterface(v, nil, ctx)
						}
					}
				}
			}
		}
	}
}

func main() {
	// Parse one file.
	fset := token.NewFileSet()
	f, err := parser.ParseFile(fset, "input.go", input, 0)
	if err != nil {
		log.Fatal(err) // parse error
	}
	conf := types.Config{Importer: importer.Default()}
	pkg, err := conf.Check("hello", fset, []*ast.File{f}, nil)
	if err != nil {
		log.Fatal(err) // type error
	}

	//!+implements
	// Find all named types at package level.
	var allNamed []*types.Named
	for _, name := range pkg.Scope().Names() {
		if obj, ok := pkg.Scope().Lookup(name).(*types.TypeName); ok {
			allNamed = append(allNamed, obj.Type().(*types.Named))
		}
	}

	// Test assignability of all distinct pairs of
	// named types (T, U) where U is an interface.
	for _, T := range allNamed {
		for _, U := range allNamed {
			if T == U || !types.IsInterface(U) {
				continue
			}
			if types.AssignableTo(T, U) {
				fmt.Printf("%s satisfies %s\n", T, U)
			} else if !types.IsInterface(T) &&
				types.AssignableTo(types.NewPointer(T), U) {
				fmt.Printf("%s satisfies %s\n", types.NewPointer(T), U)
			}
		}
	}
	//!-implements
}

func methodDocComment(prog *loader.Program, tname *types.TypeName, methodName string) (string, error) {
	t := tname.Type()
	if !types.IsInterface(t) {
		// Use the pointer type to get as many methods as possible.
		t = types.NewPointer(t)
	}

	mset := types.NewMethodSet(t)
	sel := mset.Lookup(nil, methodName)
	if sel == nil {
		return "", errgo.Newf("cannot find method %v on %v", methodName, t)
	}
	obj := sel.Obj()
	decl, err := findDecl(prog, obj.Pos())
	if err != nil {
		return "", errgo.Mask(err)
	}
	switch decl := decl.(type) {
	case *ast.GenDecl:
		if decl.Tok != token.TYPE {
			return "", errgo.Newf("found non-type decl %#v", decl)
		}
		for _, spec := range decl.Specs {
			tspec := spec.(*ast.TypeSpec)
			it := tspec.Type.(*ast.InterfaceType)
			for _, m := range it.Methods.List {
				for _, id := range m.Names {
					if id.Pos() == obj.Pos() {
						return m.Doc.Text(), nil
					}
				}
			}
		}
		return "", errgo.Newf("method definition not found in type")
	case *ast.FuncDecl:
		if decl.Name.Pos() != obj.Pos() {
			return "", errgo.Newf("method definition not found (at %#v)", prog.Fset.Position(obj.Pos()))
		}
		return decl.Doc.Text(), nil
	default:
		return "", errgo.Newf("unexpected declaration %T found", decl)
	}
}

// NewGenerator initializes a Generator that will mock the given interface from the specified package.
func NewGenerator(pkg, iface string) (*Generator, error) {
	p, err := importer.DefaultWithTestFiles().Import(pkg)
	if err != nil {
		return nil, err
	}
	obj := p.Scope().Lookup(iface)
	if obj == nil {
		return nil, fmt.Errorf("interface %s missing", iface)
	}
	if !types.IsInterface(obj.Type()) {
		return nil, fmt.Errorf("%s should be an interface, was %s", iface, obj.Type())
	}
	g := &Generator{
		ifaceName: iface,
		pkg:       p,
		iface:     obj.Type().Underlying().(*types.Interface).Complete(),
	}
	g.SetTemplate(defaultMockTemplate)
	return g, nil
}

func logType(t types.TypeAndValue) {
	if t.Type != nil {
		util.Debug("type [%s] [%s] [%s] [%s]", reflect.TypeOf(t.Type), t.Type.String(), reflect.TypeOf(t.Type.Underlying()), t.Type.Underlying().String())
		switch t.Type.(type) {
		case *types.Signature:
			s := t.Type.(*types.Signature)
			if s.Recv() != nil {
				util.Info("\t\t[%s] [%s]", s.Recv(), s.Recv().Type().String())
			}
			if tuple := s.Params(); tuple != nil {
				for i := 0; i < tuple.Len(); i++ {
					v := tuple.At(i)
					util.Debug("\t\t%s", v.Name())
					if types.IsInterface(v.Type()) {
						util.Debug("\t\t\t<------interface")
					}
				}
			}
		}
	}
}

func (p *exporter) typ(t types.Type) {
	if t == nil {
		log.Fatalf("gcimporter: nil type")
	}

	// Possible optimization: Anonymous pointer types *T where
	// T is a named type are common. We could canonicalize all
	// such types *T to a single type PT = *T. This would lead
	// to at most one *T entry in typIndex, and all future *T's
	// would be encoded as the respective index directly. Would
	// save 1 byte (pointerTag) per *T and reduce the typIndex
	// size (at the cost of a canonicalization map). We can do
	// this later, without encoding format change.

	// if we saw the type before, write its index (>= 0)
	if i, ok := p.typIndex[t]; ok {
		p.index('T', i)
		return
	}

	// otherwise, remember the type, write the type tag (< 0) and type data
	if trackAllTypes {
		if trace {
			p.tracef("T%d = {>\n", len(p.typIndex))
			defer p.tracef("<\n} ")
		}
		p.typIndex[t] = len(p.typIndex)
	}

	switch t := t.(type) {
	case *types.Named:
		if !trackAllTypes {
			// if we don't track all types, track named types now
			p.typIndex[t] = len(p.typIndex)
		}

		p.tag(namedTag)
		p.pos(t.Obj())
		p.qualifiedName(t.Obj())
		p.typ(t.Underlying())
		if !types.IsInterface(t) {
			p.assocMethods(t)
		}

	case *types.Array:
		p.tag(arrayTag)
		p.int64(t.Len())
		p.typ(t.Elem())

	case *types.Slice:
		p.tag(sliceTag)
		p.typ(t.Elem())

	case *dddSlice:
		p.tag(dddTag)
		p.typ(t.elem)

	case *types.Struct:
		p.tag(structTag)
		p.fieldList(t)

	case *types.Pointer:
		p.tag(pointerTag)
		p.typ(t.Elem())

	case *types.Signature:
		p.tag(signatureTag)
		p.paramList(t.Params(), t.Variadic())
		p.paramList(t.Results(), false)

	case *types.Interface:
		p.tag(interfaceTag)
		p.iface(t)

	case *types.Map:
		p.tag(mapTag)
		p.typ(t.Key())
		p.typ(t.Elem())

	case *types.Chan:
		p.tag(chanTag)
		p.int(int(3 - t.Dir())) // hack
		p.typ(t.Elem())

	default:
		log.Fatalf("gcimporter: unexpected type %T: %s", t, t)
	}
}

func isInterface(T types.Type) bool { return types.IsInterface(T) }

// parent is the package which declared the type; parent == nil means
// the package currently imported. The parent package is needed for
// exported struct fields and interface methods which don't contain
// explicit package information in the export data.
func (p *importer) typ(parent *types.Package) types.Type {
	// if the type was seen before, i is its index (>= 0)
	i := p.tagOrIndex()
	if i >= 0 {
		return p.typList[i]
	}

	// otherwise, i is the type tag (< 0)
	switch i {
	case namedTag:
		// read type object
		pos := p.pos()
		parent, name := p.qualifiedName()
		scope := parent.Scope()
		obj := scope.Lookup(name)

		// if the object doesn't exist yet, create and insert it
		if obj == nil {
			obj = types.NewTypeName(pos, parent, name, nil)
			scope.Insert(obj)
		}

		if _, ok := obj.(*types.TypeName); !ok {
			panic(fmt.Sprintf("pkg = %s, name = %s => %s", parent, name, obj))
		}

		// associate new named type with obj if it doesn't exist yet
		t0 := types.NewNamed(obj.(*types.TypeName), nil, nil)

		// but record the existing type, if any
		t := obj.Type().(*types.Named)
		p.record(t)

		// read underlying type
		t0.SetUnderlying(p.typ(parent))

		// interfaces don't have associated methods
		if types.IsInterface(t0) {
			return t
		}

		// read associated methods
		for i := p.int(); i > 0; i-- {
			// TODO(gri) replace this with something closer to fieldName
			pos := p.pos()
			name := p.string()
			if !exported(name) {
				p.pkg()
			}

			recv, _ := p.paramList() // TODO(gri) do we need a full param list for the receiver?
			params, isddd := p.paramList()
			result, _ := p.paramList()

			if p.version == "v1" {
				p.int() // nointerface flag - discarded
			}

			sig := types.NewSignature(recv.At(0), params, result, isddd)
			t0.AddMethod(types.NewFunc(pos, parent, name, sig))
		}

		return t

	case arrayTag:
		t := new(types.Array)
		if p.trackAllTypes {
			p.record(t)
		}

		n := p.int64()
		*t = *types.NewArray(p.typ(parent), n)
		return t

	case sliceTag:
		t := new(types.Slice)
		if p.trackAllTypes {
			p.record(t)
		}

		*t = *types.NewSlice(p.typ(parent))
		return t

	case dddTag:
		t := new(dddSlice)
		if p.trackAllTypes {
			p.record(t)
		}

		t.elem = p.typ(parent)
		return t

	case structTag:
		t := new(types.Struct)
		if p.trackAllTypes {
			p.record(t)
//.........这里部分代码省略.........

// Callees reports the possible callees of the function call site
// identified by the specified source location.
func callees(q *Query) error {
	lconf := loader.Config{Build: q.Build}

	if err := setPTAScope(&lconf, q.Scope); err != nil {
		return err
	}

	// Load/parse/type-check the program.
	lprog, err := lconf.Load()
	if err != nil {
		return err
	}
	q.Fset = lprog.Fset

	qpos, err := parseQueryPos(lprog, q.Pos, true) // needs exact pos
	if err != nil {
		return err
	}

	// Determine the enclosing call for the specified position.
	var e *ast.CallExpr
	for _, n := range qpos.path {
		if e, _ = n.(*ast.CallExpr); e != nil {
			break
		}
	}
	if e == nil {
		return fmt.Errorf("there is no function call here")
	}
	// TODO(adonovan): issue an error if the call is "too far
	// away" from the current selection, as this most likely is
	// not what the user intended.

	// Reject type conversions.
	if qpos.info.Types[e.Fun].IsType() {
		return fmt.Errorf("this is a type conversion, not a function call")
	}

	// Deal with obviously static calls before constructing SSA form.
	// Some static calls may yet require SSA construction,
	// e.g.  f := func(){}; f().
	switch funexpr := unparen(e.Fun).(type) {
	case *ast.Ident:
		switch obj := qpos.info.Uses[funexpr].(type) {
		case *types.Builtin:
			// Reject calls to built-ins.
			return fmt.Errorf("this is a call to the built-in '%s' operator", obj.Name())
		case *types.Func:
			// This is a static function call
			q.result = &calleesTypesResult{
				site:   e,
				callee: obj,
			}
			return nil
		}
	case *ast.SelectorExpr:
		sel := qpos.info.Selections[funexpr]
		if sel == nil {
			// qualified identifier.
			// May refer to top level function variable
			// or to top level function.
			callee := qpos.info.Uses[funexpr.Sel]
			if obj, ok := callee.(*types.Func); ok {
				q.result = &calleesTypesResult{
					site:   e,
					callee: obj,
				}
				return nil
			}
		} else if sel.Kind() == types.MethodVal {
			// Inspect the receiver type of the selected method.
			// If it is concrete, the call is statically dispatched.
			// (Due to implicit field selections, it is not enough to look
			// at sel.Recv(), the type of the actual receiver expression.)
			method := sel.Obj().(*types.Func)
			recvtype := method.Type().(*types.Signature).Recv().Type()
			if !types.IsInterface(recvtype) {
				// static method call
				q.result = &calleesTypesResult{
					site:   e,
					callee: method,
				}
				return nil
			}
		}
	}

	prog := ssautil.CreateProgram(lprog, ssa.GlobalDebug)

	ptaConfig, err := setupPTA(prog, lprog, q.PTALog, q.Reflection)
	if err != nil {
		return err
	}

	pkg := prog.Package(qpos.info.Pkg)
	if pkg == nil {
		return fmt.Errorf("no SSA package")
	}
//.........这里部分代码省略.........

// CreateTestMainPackage creates and returns a synthetic "testmain"
// package for the specified package if it defines tests, benchmarks or
// executable examples, or nil otherwise.  The new package is named
// "main" and provides a function named "main" that runs the tests,
// similar to the one that would be created by the 'go test' tool.
//
// Subsequent calls to prog.AllPackages include the new package.
// The package pkg must belong to the program prog.
func (prog *Program) CreateTestMainPackage(pkg *Package) *Package {
	if pkg.Prog != prog {
		log.Fatal("Package does not belong to Program")
	}

	// Template data
	var data struct {
		Pkg                         *Package
		Tests, Benchmarks, Examples []*Function
		Main                        *Function
		Go18                        bool
	}
	data.Pkg = pkg

	// Enumerate tests.
	data.Tests, data.Benchmarks, data.Examples, data.Main = FindTests(pkg)
	if data.Main == nil &&
		data.Tests == nil && data.Benchmarks == nil && data.Examples == nil {
		return nil
	}

	// Synthesize source for testmain package.
	path := pkg.Pkg.Path() + "$testmain"
	tmpl := testmainTmpl
	if testingPkg := prog.ImportedPackage("testing"); testingPkg != nil {
		// In Go 1.8, testing.MainStart's first argument is an interface, not a func.
		data.Go18 = types.IsInterface(testingPkg.Func("MainStart").Signature.Params().At(0).Type())
	} else {
		// The program does not import "testing", but FindTests
		// returned non-nil, which must mean there were Examples
		// but no Test, Benchmark, or TestMain functions.

		// We'll simply call them from testmain.main; this will
		// ensure they don't panic, but will not check any
		// "Output:" comments.
		// (We should not execute an Example that has no
		// "Output:" comment, but it's impossible to tell here.)
		tmpl = examplesOnlyTmpl
	}
	var buf bytes.Buffer
	if err := tmpl.Execute(&buf, data); err != nil {
		log.Fatalf("internal error expanding template for %s: %v", path, err)
	}
	if false { // debugging
		fmt.Fprintln(os.Stderr, buf.String())
	}

	// Parse and type-check the testmain package.
	f, err := parser.ParseFile(prog.Fset, path+".go", &buf, parser.Mode(0))
	if err != nil {
		log.Fatalf("internal error parsing %s: %v", path, err)
	}
	conf := types.Config{
		DisableUnusedImportCheck: true,
		Importer:                 importer{pkg},
	}
	files := []*ast.File{f}
	info := &types.Info{
		Types:      make(map[ast.Expr]types.TypeAndValue),
		Defs:       make(map[*ast.Ident]types.Object),
		Uses:       make(map[*ast.Ident]types.Object),
		Implicits:  make(map[ast.Node]types.Object),
		Scopes:     make(map[ast.Node]*types.Scope),
		Selections: make(map[*ast.SelectorExpr]*types.Selection),
	}
	testmainPkg, err := conf.Check(path, prog.Fset, files, info)
	if err != nil {
		log.Fatalf("internal error type-checking %s: %v", path, err)
	}

	// Create and build SSA code.
	testmain := prog.CreatePackage(testmainPkg, files, info, false)
	testmain.SetDebugMode(false)
	testmain.Build()
	testmain.Func("main").Synthetic = "test main function"
	testmain.Func("init").Synthetic = "package initializer"
	return testmain
}