mirror of
https://github.com/golang/go
synced 2024-11-23 06:20:07 -07:00
[dev.typeparams] go/types: move signature checking into separate file
This is a port of CL 321590 to go/types. Specifically, the same checker methods were moved. Change-Id: If4522d316f29c6b6f887580aa037e6b6dedbb6ac Reviewed-on: https://go-review.googlesource.com/c/go/+/324754 Trust: Robert Findley <rfindley@google.com> Run-TryBot: Robert Findley <rfindley@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Robert Griesemer <gri@golang.org>
This commit is contained in:
Rob Findley
Robert Findley
parent
c23294d6b3
commit
991dca0112
274
src/go/types/signature.go
Normal file
274
src/go/types/signature.go
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@ -0,0 +1,274 @@
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// Copyright 2021 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package types
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import (
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"fmt"
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"go/ast"
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"go/internal/typeparams"
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"go/token"
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)
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// funcType type-checks a function or method type.
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func (check *Checker) funcType(sig *Signature, recvPar *ast.FieldList, ftyp *ast.FuncType) {
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check.openScope(ftyp, "function")
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check.scope.isFunc = true
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check.recordScope(ftyp, check.scope)
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sig.scope = check.scope
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defer check.closeScope()
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var recvTyp ast.Expr // rewritten receiver type; valid if != nil
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if recvPar != nil && len(recvPar.List) > 0 {
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// collect generic receiver type parameters, if any
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// - a receiver type parameter is like any other type parameter, except that it is declared implicitly
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// - the receiver specification acts as local declaration for its type parameters, which may be blank
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_, rname, rparams := check.unpackRecv(recvPar.List[0].Type, true)
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if len(rparams) > 0 {
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// Blank identifiers don't get declared and regular type-checking of the instantiated
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// parameterized receiver type expression fails in Checker.collectParams of receiver.
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// Identify blank type parameters and substitute each with a unique new identifier named
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// "n_" (where n is the parameter index) and which cannot conflict with any user-defined
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// name.
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var smap map[*ast.Ident]*ast.Ident // substitution map from "_" to "n_" identifiers
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for i, p := range rparams {
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if p.Name == "_" {
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new := *p
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new.Name = fmt.Sprintf("%d_", i)
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rparams[i] = &new // use n_ identifier instead of _ so it can be looked up
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if smap == nil {
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smap = make(map[*ast.Ident]*ast.Ident)
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}
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smap[p] = &new
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}
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}
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if smap != nil {
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// blank identifiers were found => use rewritten receiver type
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recvTyp = isubst(recvPar.List[0].Type, smap)
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}
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sig.rparams = check.declareTypeParams(nil, rparams)
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// determine receiver type to get its type parameters
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// and the respective type parameter bounds
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var recvTParams []*TypeName
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if rname != nil {
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// recv should be a Named type (otherwise an error is reported elsewhere)
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// Also: Don't report an error via genericType since it will be reported
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// again when we type-check the signature.
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// TODO(gri) maybe the receiver should be marked as invalid instead?
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if recv := asNamed(check.genericType(rname, false)); recv != nil {
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recvTParams = recv.tparams
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}
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}
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// provide type parameter bounds
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// - only do this if we have the right number (otherwise an error is reported elsewhere)
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if len(sig.rparams) == len(recvTParams) {
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// We have a list of *TypeNames but we need a list of Types.
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list := make([]Type, len(sig.rparams))
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for i, t := range sig.rparams {
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list[i] = t.typ
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}
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smap := makeSubstMap(recvTParams, list)
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for i, tname := range sig.rparams {
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bound := recvTParams[i].typ.(*_TypeParam).bound
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// bound is (possibly) parameterized in the context of the
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// receiver type declaration. Substitute parameters for the
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// current context.
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// TODO(gri) should we assume now that bounds always exist?
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// (no bound == empty interface)
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if bound != nil {
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bound = check.subst(tname.pos, bound, smap)
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tname.typ.(*_TypeParam).bound = bound
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}
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}
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}
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}
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}
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if tparams := typeparams.Get(ftyp); tparams != nil {
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sig.tparams = check.collectTypeParams(tparams)
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// Always type-check method type parameters but complain that they are not allowed.
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// (A separate check is needed when type-checking interface method signatures because
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// they don't have a receiver specification.)
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if recvPar != nil {
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check.errorf(tparams, _Todo, "methods cannot have type parameters")
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}
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}
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// Value (non-type) parameters' scope starts in the function body. Use a temporary scope for their
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// declarations and then squash that scope into the parent scope (and report any redeclarations at
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// that time).
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scope := NewScope(check.scope, token.NoPos, token.NoPos, "function body (temp. scope)")
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recvList, _ := check.collectParams(scope, recvPar, recvTyp, false) // use rewritten receiver type, if any
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params, variadic := check.collectParams(scope, ftyp.Params, nil, true)
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results, _ := check.collectParams(scope, ftyp.Results, nil, false)
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scope.squash(func(obj, alt Object) {
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check.errorf(obj, _DuplicateDecl, "%s redeclared in this block", obj.Name())
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check.reportAltDecl(alt)
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})
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if recvPar != nil {
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// recv parameter list present (may be empty)
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// spec: "The receiver is specified via an extra parameter section preceding the
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// method name. That parameter section must declare a single parameter, the receiver."
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var recv *Var
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switch len(recvList) {
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case 0:
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// error reported by resolver
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recv = NewParam(0, nil, "", Typ[Invalid]) // ignore recv below
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default:
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// more than one receiver
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check.error(recvList[len(recvList)-1], _BadRecv, "method must have exactly one receiver")
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fallthrough // continue with first receiver
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case 1:
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recv = recvList[0]
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}
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// TODO(gri) We should delay rtyp expansion to when we actually need the
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// receiver; thus all checks here should be delayed to later.
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rtyp, _ := deref(recv.typ)
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rtyp = expand(rtyp)
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// spec: "The receiver type must be of the form T or *T where T is a type name."
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// (ignore invalid types - error was reported before)
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if t := rtyp; t != Typ[Invalid] {
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var err string
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if T := asNamed(t); T != nil {
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// spec: "The type denoted by T is called the receiver base type; it must not
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// be a pointer or interface type and it must be declared in the same package
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// as the method."
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if T.obj.pkg != check.pkg {
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err = "type not defined in this package"
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} else {
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switch u := optype(T).(type) {
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case *Basic:
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// unsafe.Pointer is treated like a regular pointer
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if u.kind == UnsafePointer {
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err = "unsafe.Pointer"
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}
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case *Pointer, *Interface:
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err = "pointer or interface type"
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}
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}
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} else {
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err = "basic or unnamed type"
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}
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if err != "" {
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check.errorf(recv, _InvalidRecv, "invalid receiver %s (%s)", recv.typ, err)
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// ok to continue
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}
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}
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sig.recv = recv
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}
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sig.params = NewTuple(params...)
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sig.results = NewTuple(results...)
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sig.variadic = variadic
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}
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// collectParams declares the parameters of list in scope and returns the corresponding
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// variable list. If type0 != nil, it is used instead of the first type in list.
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func (check *Checker) collectParams(scope *Scope, list *ast.FieldList, type0 ast.Expr, variadicOk bool) (params []*Var, variadic bool) {
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if list == nil {
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return
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}
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var named, anonymous bool
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for i, field := range list.List {
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ftype := field.Type
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if i == 0 && type0 != nil {
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ftype = type0
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}
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if t, _ := ftype.(*ast.Ellipsis); t != nil {
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ftype = t.Elt
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if variadicOk && i == len(list.List)-1 && len(field.Names) <= 1 {
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variadic = true
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} else {
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check.softErrorf(t, _MisplacedDotDotDot, "can only use ... with final parameter in list")
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// ignore ... and continue
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}
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}
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typ := check.varType(ftype)
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// The parser ensures that f.Tag is nil and we don't
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// care if a constructed AST contains a non-nil tag.
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if len(field.Names) > 0 {
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// named parameter
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for _, name := range field.Names {
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if name.Name == "" {
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check.invalidAST(name, "anonymous parameter")
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// ok to continue
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}
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par := NewParam(name.Pos(), check.pkg, name.Name, typ)
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check.declare(scope, name, par, scope.pos)
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params = append(params, par)
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}
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named = true
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} else {
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// anonymous parameter
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par := NewParam(ftype.Pos(), check.pkg, "", typ)
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check.recordImplicit(field, par)
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params = append(params, par)
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anonymous = true
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}
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}
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if named && anonymous {
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check.invalidAST(list, "list contains both named and anonymous parameters")
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// ok to continue
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}
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// For a variadic function, change the last parameter's type from T to []T.
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// Since we type-checked T rather than ...T, we also need to retro-actively
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// record the type for ...T.
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if variadic {
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last := params[len(params)-1]
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last.typ = &Slice{elem: last.typ}
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check.recordTypeAndValue(list.List[len(list.List)-1].Type, typexpr, last.typ, nil)
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}
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return
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}
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// isubst returns an x with identifiers substituted per the substitution map smap.
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// isubst only handles the case of (valid) method receiver type expressions correctly.
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func isubst(x ast.Expr, smap map[*ast.Ident]*ast.Ident) ast.Expr {
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switch n := x.(type) {
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case *ast.Ident:
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if alt := smap[n]; alt != nil {
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return alt
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}
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case *ast.StarExpr:
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X := isubst(n.X, smap)
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if X != n.X {
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new := *n
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new.X = X
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return &new
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}
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case *ast.IndexExpr:
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elems := typeparams.UnpackExpr(n.Index)
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var newElems []ast.Expr
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for i, elem := range elems {
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new := isubst(elem, smap)
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if new != elem {
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if newElems == nil {
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newElems = make([]ast.Expr, len(elems))
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copy(newElems, elems)
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}
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newElems[i] = new
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}
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}
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if newElems != nil {
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index := typeparams.PackExpr(newElems)
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new := *n
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new.Index = index
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return &new
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}
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case *ast.ParenExpr:
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return isubst(n.X, smap) // no need to keep parentheses
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default:
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// Other receiver type expressions are invalid.
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// It's fine to ignore those here as they will
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// be checked elsewhere.
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}
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return x
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}
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@ -192,205 +192,6 @@ func (check *Checker) genericType(e ast.Expr, reportErr bool) Type {
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return typ
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return typ
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}
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}
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// isubst returns an x with identifiers substituted per the substitution map smap.
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// isubst only handles the case of (valid) method receiver type expressions correctly.
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func isubst(x ast.Expr, smap map[*ast.Ident]*ast.Ident) ast.Expr {
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switch n := x.(type) {
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case *ast.Ident:
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if alt := smap[n]; alt != nil {
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return alt
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}
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case *ast.StarExpr:
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X := isubst(n.X, smap)
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if X != n.X {
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new := *n
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new.X = X
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return &new
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}
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case *ast.IndexExpr:
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elems := typeparams.UnpackExpr(n.Index)
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var newElems []ast.Expr
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for i, elem := range elems {
|
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new := isubst(elem, smap)
|
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if new != elem {
|
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if newElems == nil {
|
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newElems = make([]ast.Expr, len(elems))
|
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copy(newElems, elems)
|
|
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}
|
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newElems[i] = new
|
|
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}
|
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}
|
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if newElems != nil {
|
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index := typeparams.PackExpr(newElems)
|
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new := *n
|
|
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new.Index = index
|
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return &new
|
|
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}
|
|
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case *ast.ParenExpr:
|
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return isubst(n.X, smap) // no need to keep parentheses
|
|
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default:
|
|
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// Other receiver type expressions are invalid.
|
|
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// It's fine to ignore those here as they will
|
|
||||||
// be checked elsewhere.
|
|
||||||
}
|
|
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return x
|
|
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}
|
|
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|
|
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// funcType type-checks a function or method type.
|
|
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func (check *Checker) funcType(sig *Signature, recvPar *ast.FieldList, ftyp *ast.FuncType) {
|
|
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check.openScope(ftyp, "function")
|
|
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check.scope.isFunc = true
|
|
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check.recordScope(ftyp, check.scope)
|
|
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sig.scope = check.scope
|
|
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defer check.closeScope()
|
|
||||||
|
|
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var recvTyp ast.Expr // rewritten receiver type; valid if != nil
|
|
||||||
if recvPar != nil && len(recvPar.List) > 0 {
|
|
||||||
// collect generic receiver type parameters, if any
|
|
||||||
// - a receiver type parameter is like any other type parameter, except that it is declared implicitly
|
|
||||||
// - the receiver specification acts as local declaration for its type parameters, which may be blank
|
|
||||||
_, rname, rparams := check.unpackRecv(recvPar.List[0].Type, true)
|
|
||||||
if len(rparams) > 0 {
|
|
||||||
// Blank identifiers don't get declared and regular type-checking of the instantiated
|
|
||||||
// parameterized receiver type expression fails in Checker.collectParams of receiver.
|
|
||||||
// Identify blank type parameters and substitute each with a unique new identifier named
|
|
||||||
// "n_" (where n is the parameter index) and which cannot conflict with any user-defined
|
|
||||||
// name.
|
|
||||||
var smap map[*ast.Ident]*ast.Ident // substitution map from "_" to "n_" identifiers
|
|
||||||
for i, p := range rparams {
|
|
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if p.Name == "_" {
|
|
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new := *p
|
|
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new.Name = fmt.Sprintf("%d_", i)
|
|
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rparams[i] = &new // use n_ identifier instead of _ so it can be looked up
|
|
||||||
if smap == nil {
|
|
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smap = make(map[*ast.Ident]*ast.Ident)
|
|
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}
|
|
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smap[p] = &new
|
|
||||||
}
|
|
||||||
}
|
|
||||||
if smap != nil {
|
|
||||||
// blank identifiers were found => use rewritten receiver type
|
|
||||||
recvTyp = isubst(recvPar.List[0].Type, smap)
|
|
||||||
}
|
|
||||||
sig.rparams = check.declareTypeParams(nil, rparams)
|
|
||||||
// determine receiver type to get its type parameters
|
|
||||||
// and the respective type parameter bounds
|
|
||||||
var recvTParams []*TypeName
|
|
||||||
if rname != nil {
|
|
||||||
// recv should be a Named type (otherwise an error is reported elsewhere)
|
|
||||||
// Also: Don't report an error via genericType since it will be reported
|
|
||||||
// again when we type-check the signature.
|
|
||||||
// TODO(gri) maybe the receiver should be marked as invalid instead?
|
|
||||||
if recv := asNamed(check.genericType(rname, false)); recv != nil {
|
|
||||||
recvTParams = recv.tparams
|
|
||||||
}
|
|
||||||
}
|
|
||||||
// provide type parameter bounds
|
|
||||||
// - only do this if we have the right number (otherwise an error is reported elsewhere)
|
|
||||||
if len(sig.rparams) == len(recvTParams) {
|
|
||||||
// We have a list of *TypeNames but we need a list of Types.
|
|
||||||
list := make([]Type, len(sig.rparams))
|
|
||||||
for i, t := range sig.rparams {
|
|
||||||
list[i] = t.typ
|
|
||||||
}
|
|
||||||
smap := makeSubstMap(recvTParams, list)
|
|
||||||
for i, tname := range sig.rparams {
|
|
||||||
bound := recvTParams[i].typ.(*_TypeParam).bound
|
|
||||||
// bound is (possibly) parameterized in the context of the
|
|
||||||
// receiver type declaration. Substitute parameters for the
|
|
||||||
// current context.
|
|
||||||
// TODO(gri) should we assume now that bounds always exist?
|
|
||||||
// (no bound == empty interface)
|
|
||||||
if bound != nil {
|
|
||||||
bound = check.subst(tname.pos, bound, smap)
|
|
||||||
tname.typ.(*_TypeParam).bound = bound
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
if tparams := typeparams.Get(ftyp); tparams != nil {
|
|
||||||
sig.tparams = check.collectTypeParams(tparams)
|
|
||||||
// Always type-check method type parameters but complain that they are not allowed.
|
|
||||||
// (A separate check is needed when type-checking interface method signatures because
|
|
||||||
// they don't have a receiver specification.)
|
|
||||||
if recvPar != nil {
|
|
||||||
check.errorf(tparams, _Todo, "methods cannot have type parameters")
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
// Value (non-type) parameters' scope starts in the function body. Use a temporary scope for their
|
|
||||||
// declarations and then squash that scope into the parent scope (and report any redeclarations at
|
|
||||||
// that time).
|
|
||||||
scope := NewScope(check.scope, token.NoPos, token.NoPos, "function body (temp. scope)")
|
|
||||||
recvList, _ := check.collectParams(scope, recvPar, recvTyp, false) // use rewritten receiver type, if any
|
|
||||||
params, variadic := check.collectParams(scope, ftyp.Params, nil, true)
|
|
||||||
results, _ := check.collectParams(scope, ftyp.Results, nil, false)
|
|
||||||
scope.squash(func(obj, alt Object) {
|
|
||||||
check.errorf(obj, _DuplicateDecl, "%s redeclared in this block", obj.Name())
|
|
||||||
check.reportAltDecl(alt)
|
|
||||||
})
|
|
||||||
|
|
||||||
if recvPar != nil {
|
|
||||||
// recv parameter list present (may be empty)
|
|
||||||
// spec: "The receiver is specified via an extra parameter section preceding the
|
|
||||||
// method name. That parameter section must declare a single parameter, the receiver."
|
|
||||||
var recv *Var
|
|
||||||
switch len(recvList) {
|
|
||||||
case 0:
|
|
||||||
// error reported by resolver
|
|
||||||
recv = NewParam(0, nil, "", Typ[Invalid]) // ignore recv below
|
|
||||||
default:
|
|
||||||
// more than one receiver
|
|
||||||
check.error(recvList[len(recvList)-1], _BadRecv, "method must have exactly one receiver")
|
|
||||||
fallthrough // continue with first receiver
|
|
||||||
case 1:
|
|
||||||
recv = recvList[0]
|
|
||||||
}
|
|
||||||
|
|
||||||
// TODO(gri) We should delay rtyp expansion to when we actually need the
|
|
||||||
// receiver; thus all checks here should be delayed to later.
|
|
||||||
rtyp, _ := deref(recv.typ)
|
|
||||||
rtyp = expand(rtyp)
|
|
||||||
|
|
||||||
// spec: "The receiver type must be of the form T or *T where T is a type name."
|
|
||||||
// (ignore invalid types - error was reported before)
|
|
||||||
if t := rtyp; t != Typ[Invalid] {
|
|
||||||
var err string
|
|
||||||
if T := asNamed(t); T != nil {
|
|
||||||
// spec: "The type denoted by T is called the receiver base type; it must not
|
|
||||||
// be a pointer or interface type and it must be declared in the same package
|
|
||||||
// as the method."
|
|
||||||
if T.obj.pkg != check.pkg {
|
|
||||||
err = "type not defined in this package"
|
|
||||||
} else {
|
|
||||||
switch u := optype(T).(type) {
|
|
||||||
case *Basic:
|
|
||||||
// unsafe.Pointer is treated like a regular pointer
|
|
||||||
if u.kind == UnsafePointer {
|
|
||||||
err = "unsafe.Pointer"
|
|
||||||
}
|
|
||||||
case *Pointer, *Interface:
|
|
||||||
err = "pointer or interface type"
|
|
||||||
}
|
|
||||||
}
|
|
||||||
} else {
|
|
||||||
err = "basic or unnamed type"
|
|
||||||
}
|
|
||||||
if err != "" {
|
|
||||||
check.errorf(recv, _InvalidRecv, "invalid receiver %s (%s)", recv.typ, err)
|
|
||||||
// ok to continue
|
|
||||||
}
|
|
||||||
}
|
|
||||||
sig.recv = recv
|
|
||||||
}
|
|
||||||
|
|
||||||
sig.params = NewTuple(params...)
|
|
||||||
sig.results = NewTuple(results...)
|
|
||||||
sig.variadic = variadic
|
|
||||||
}
|
|
||||||
|
|
||||||
// goTypeName returns the Go type name for typ and
|
// goTypeName returns the Go type name for typ and
|
||||||
// removes any occurrences of "types." from that name.
|
// removes any occurrences of "types." from that name.
|
||||||
func goTypeName(typ Type) string {
|
func goTypeName(typ Type) string {
|
||||||
@ -683,66 +484,3 @@ func (check *Checker) typeList(list []ast.Expr) []Type {
|
|||||||
}
|
}
|
||||||
return res
|
return res
|
||||||
}
|
}
|
||||||
|
|
||||||
// collectParams declares the parameters of list in scope and returns the corresponding
|
|
||||||
// variable list. If type0 != nil, it is used instead of the first type in list.
|
|
||||||
func (check *Checker) collectParams(scope *Scope, list *ast.FieldList, type0 ast.Expr, variadicOk bool) (params []*Var, variadic bool) {
|
|
||||||
if list == nil {
|
|
||||||
return
|
|
||||||
}
|
|
||||||
|
|
||||||
var named, anonymous bool
|
|
||||||
for i, field := range list.List {
|
|
||||||
ftype := field.Type
|
|
||||||
if i == 0 && type0 != nil {
|
|
||||||
ftype = type0
|
|
||||||
}
|
|
||||||
if t, _ := ftype.(*ast.Ellipsis); t != nil {
|
|
||||||
ftype = t.Elt
|
|
||||||
if variadicOk && i == len(list.List)-1 && len(field.Names) <= 1 {
|
|
||||||
variadic = true
|
|
||||||
} else {
|
|
||||||
check.softErrorf(t, _MisplacedDotDotDot, "can only use ... with final parameter in list")
|
|
||||||
// ignore ... and continue
|
|
||||||
}
|
|
||||||
}
|
|
||||||
typ := check.varType(ftype)
|
|
||||||
// The parser ensures that f.Tag is nil and we don't
|
|
||||||
// care if a constructed AST contains a non-nil tag.
|
|
||||||
if len(field.Names) > 0 {
|
|
||||||
// named parameter
|
|
||||||
for _, name := range field.Names {
|
|
||||||
if name.Name == "" {
|
|
||||||
check.invalidAST(name, "anonymous parameter")
|
|
||||||
// ok to continue
|
|
||||||
}
|
|
||||||
par := NewParam(name.Pos(), check.pkg, name.Name, typ)
|
|
||||||
check.declare(scope, name, par, scope.pos)
|
|
||||||
params = append(params, par)
|
|
||||||
}
|
|
||||||
named = true
|
|
||||||
} else {
|
|
||||||
// anonymous parameter
|
|
||||||
par := NewParam(ftype.Pos(), check.pkg, "", typ)
|
|
||||||
check.recordImplicit(field, par)
|
|
||||||
params = append(params, par)
|
|
||||||
anonymous = true
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
if named && anonymous {
|
|
||||||
check.invalidAST(list, "list contains both named and anonymous parameters")
|
|
||||||
// ok to continue
|
|
||||||
}
|
|
||||||
|
|
||||||
// For a variadic function, change the last parameter's type from T to []T.
|
|
||||||
// Since we type-checked T rather than ...T, we also need to retro-actively
|
|
||||||
// record the type for ...T.
|
|
||||||
if variadic {
|
|
||||||
last := params[len(params)-1]
|
|
||||||
last.typ = &Slice{elem: last.typ}
|
|
||||||
check.recordTypeAndValue(list.List[len(list.List)-1].Type, typexpr, last.typ, nil)
|
|
||||||
}
|
|
||||||
|
|
||||||
return
|
|
||||||
}
|
|
||||||
|
|||||||
Loading…
Reference in New Issue
Block a user