import (
"cmd/compile/internal/syntax"
"fmt"
+ . "internal/types/errors"
)
// ----------------------------------------------------------------------------
// and store it in the Func Object) because when type-checking a function
// literal we call the general type checker which returns a general Type.
// We then unpack the *Signature and use the scope for the literal body.
- rparams *TypeParams // receiver type parameters from left to right, or nil
- tparams *TypeParams // type parameters from left to right, or nil
- scope *Scope // function scope, present for package-local signatures
- recv *Var // nil if not a method
- params *Tuple // (incoming) parameters from left to right; or nil
- results *Tuple // (outgoing) results from left to right; or nil
- variadic bool // true if the last parameter's type is of the form ...T (or string, for append built-in only)
+ rparams *TypeParamList // receiver type parameters from left to right, or nil
+ tparams *TypeParamList // type parameters from left to right, or nil
+ scope *Scope // function scope for package-local and non-instantiated signatures; nil otherwise
+ recv *Var // nil if not a method
+ params *Tuple // (incoming) parameters from left to right; or nil
+ results *Tuple // (outgoing) results from left to right; or nil
+ variadic bool // true if the last parameter's type is of the form ...T (or string, for append built-in only)
}
-// NewSignature returns a new function type for the given receiver, parameters,
-// and results, either of which may be nil. If variadic is set, the function
-// is variadic, it must have at least one parameter, and the last parameter
-// must be of unnamed slice type.
-func NewSignature(recv *Var, params, results *Tuple, variadic bool) *Signature {
+// NewSignatureType creates a new function type for the given receiver,
+// receiver type parameters, type parameters, parameters, and results. If
+// variadic is set, params must hold at least one parameter and the last
+// parameter's core type must be of unnamed slice or bytestring type.
+// If recv is non-nil, typeParams must be empty. If recvTypeParams is
+// non-empty, recv must be non-nil.
+func NewSignatureType(recv *Var, recvTypeParams, typeParams []*TypeParam, params, results *Tuple, variadic bool) *Signature {
if variadic {
n := params.Len()
if n == 0 {
panic("variadic function must have at least one parameter")
}
- if _, ok := params.At(n - 1).typ.(*Slice); !ok {
- panic("variadic parameter must be of unnamed slice type")
+ core := coreString(params.At(n - 1).typ)
+ if _, ok := core.(*Slice); !ok && !isString(core) {
+ panic(fmt.Sprintf("got %s, want variadic parameter with unnamed slice type or string as core type", core.String()))
}
}
- return &Signature{recv: recv, params: params, results: results, variadic: variadic}
+ sig := &Signature{recv: recv, params: params, results: results, variadic: variadic}
+ if len(recvTypeParams) != 0 {
+ if recv == nil {
+ panic("function with receiver type parameters must have a receiver")
+ }
+ sig.rparams = bindTParams(recvTypeParams)
+ }
+ if len(typeParams) != 0 {
+ if recv != nil {
+ panic("function with type parameters cannot have a receiver")
+ }
+ sig.tparams = bindTParams(typeParams)
+ }
+ return sig
}
// Recv returns the receiver of signature s (if a method), or nil if a
// contain methods whose receiver type is a different interface.
func (s *Signature) Recv() *Var { return s.recv }
-// TParams returns the type parameters of signature s, or nil.
-func (s *Signature) TParams() *TypeParams { return s.tparams }
-
-// SetTParams sets the type parameters of signature s.
-func (s *Signature) SetTParams(tparams []*TypeName) { s.tparams = bindTParams(tparams) }
+// TypeParams returns the type parameters of signature s, or nil.
+func (s *Signature) TypeParams() *TypeParamList { return s.tparams }
-// RParams returns the receiver type parameters of signature s, or nil.
-func (s *Signature) RParams() *TypeParams { return s.rparams }
+// SetTypeParams sets the type parameters of signature s.
+func (s *Signature) SetTypeParams(tparams []*TypeParam) { s.tparams = bindTParams(tparams) }
-// SetRParams sets the receiver type params of signature s.
-func (s *Signature) SetRParams(rparams []*TypeName) { s.rparams = bindTParams(rparams) }
+// RecvTypeParams returns the receiver type parameters of signature s, or nil.
+func (s *Signature) RecvTypeParams() *TypeParamList { return s.rparams }
// Params returns the parameters of signature s, or nil.
func (s *Signature) Params() *Tuple { return s.params }
// ----------------------------------------------------------------------------
// Implementation
-// Disabled by default, but enabled when running tests (via types_test.go).
-var acceptMethodTypeParams bool
-
// funcType type-checks a function or method type.
func (check *Checker) funcType(sig *Signature, recvPar *syntax.Field, tparams []*syntax.Field, ftyp *syntax.FuncType) {
check.openScope(ftyp, "function")
sig.scope = check.scope
defer check.closeScope()
- var recvTyp syntax.Expr // rewritten receiver type; valid if != nil
if recvPar != nil {
// 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.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[*syntax.Name]*syntax.Name // substitution map from "_" to "!n" identifiers
+ tparams := make([]*TypeParam, len(rparams))
+ for i, rparam := range rparams {
+ tparams[i] = check.declareTypeParam(rparam)
+ }
+ sig.rparams = bindTParams(tparams)
+ // Blank identifiers don't get declared, so naive type-checking of the
+ // receiver type expression would fail in Checker.collectParams below,
+ // when Checker.ident cannot resolve the _ to a type.
+ //
+ // Checker.recvTParamMap maps these blank identifiers to their type parameter
+ // types, so that they may be resolved in Checker.ident when they fail
+ // lookup in the scope.
for i, p := range rparams {
if p.Value == "_" {
- new := *p
- new.Value = fmt.Sprintf("%d_", i)
- rparams[i] = &new // use n_ identifier instead of _ so it can be looked up
- if smap == nil {
- smap = make(map[*syntax.Name]*syntax.Name)
+ if check.recvTParamMap == nil {
+ check.recvTParamMap = make(map[*syntax.Name]*TypeParam)
}
- smap[p] = &new
+ check.recvTParamMap[p] = tparams[i]
}
}
- if smap != nil {
- // blank identifiers were found => use rewritten receiver type
- recvTyp = isubst(recvPar.Type, smap)
- }
- rlist := make([]*TypeName, len(rparams))
- for i, rparam := range rparams {
- rlist[i] = check.declareTypeParam(rparam)
- }
- sig.rparams = bindTParams(rlist)
// determine receiver type to get its type parameters
// and the respective type parameter bounds
- var recvTParams []*TypeName
+ var recvTParams []*TypeParam
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().list()
+ if recv := asNamed(check.genericType(rname, nil)); recv != nil {
+ recvTParams = recv.TypeParams().list()
}
}
// provide type parameter bounds
- // - only do this if we have the right number (otherwise an error is reported elsewhere)
- if sig.RParams().Len() == len(recvTParams) {
- // We have a list of *TypeNames but we need a list of Types.
- list := make([]Type, sig.RParams().Len())
- for i, t := range sig.RParams().list() {
- list[i] = t.typ
- }
- smap := makeSubstMap(recvTParams, list)
- for i, tname := range sig.RParams().list() {
- 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 len(tparams) == len(recvTParams) {
+ smap := makeRenameMap(recvTParams, tparams)
+ for i, tpar := range tparams {
+ recvTPar := recvTParams[i]
+ check.mono.recordCanon(tpar, recvTPar)
+ // recvTPar.bound is (possibly) parameterized in the context of the
+ // receiver type declaration. Substitute parameters for the current
+ // context.
+ tpar.bound = check.subst(tpar.obj.pos, recvTPar.bound, smap, nil, check.context())
}
+ } else if len(tparams) < len(recvTParams) {
+ // Reporting an error here is a stop-gap measure to avoid crashes in the
+ // compiler when a type parameter/argument cannot be inferred later. It
+ // may lead to follow-on errors (see issues go.dev/issue/51339, go.dev/issue/51343).
+ // TODO(gri) find a better solution
+ got := measure(len(tparams), "type parameter")
+ check.errorf(recvPar, BadRecv, "got %s, but receiver base type declares %d", got, len(recvTParams))
}
}
}
if tparams != nil {
- sig.tparams = check.collectTypeParams(tparams)
- // Always type-check method type parameters but complain if they are not enabled.
- // (A separate check is needed when type-checking interface method signatures because
- // they don't have a receiver specification.)
- if recvPar != nil && !acceptMethodTypeParams {
- check.error(ftyp, "methods cannot have type parameters")
- }
+ // The parser will complain about invalid type parameters for methods.
+ check.collectTypeParams(&sig.tparams, tparams)
}
// Value (non-type) parameters' scope starts in the function body. Use a temporary scope for their
scope := NewScope(check.scope, nopos, nopos, "function body (temp. scope)")
var recvList []*Var // TODO(gri) remove the need for making a list here
if recvPar != nil {
- recvList, _ = check.collectParams(scope, []*syntax.Field{recvPar}, recvTyp, false) // use rewritten receiver type, if any
+ recvList, _ = check.collectParams(scope, []*syntax.Field{recvPar}, false) // use rewritten receiver type, if any
}
- params, variadic := check.collectParams(scope, ftyp.ParamList, nil, true)
- results, _ := check.collectParams(scope, ftyp.ResultList, nil, false)
+ params, variadic := check.collectParams(scope, ftyp.ParamList, true)
+ results, _ := check.collectParams(scope, ftyp.ResultList, false)
scope.Squash(func(obj, alt Object) {
var err error_
+ err.code = DuplicateDecl
err.errorf(obj, "%s redeclared in this block", obj.Name())
err.recordAltDecl(alt)
check.report(&err)
recv = NewParam(nopos, nil, "", Typ[Invalid]) // ignore recv below
default:
// more than one receiver
- check.error(recvList[len(recvList)-1].Pos(), "method must have exactly one receiver")
+ check.error(recvList[len(recvList)-1].Pos(), InvalidRecv, "method must have exactly one receiver")
fallthrough // continue with first receiver
case 1:
recv = recvList[0]
}
+ sig.recv = recv
- // 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)
-
- // 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 rtyp != Typ[Invalid] {
- var err string
- switch T := rtyp.(type) {
+ // Delay validation of receiver type as it may cause premature expansion
+ // of types the receiver type is dependent on (see issues go.dev/issue/51232, go.dev/issue/51233).
+ check.later(func() {
+ // spec: "The receiver type must be of the form T or *T where T is a type name."
+ rtyp, _ := deref(recv.typ)
+ atyp := _Unalias(rtyp)
+ if !isValid(atyp) {
+ return // error was reported before
+ }
+ // 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."
+ switch T := atyp.(type) {
case *Named:
- T.expand()
- // 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."
+ // The receiver type may be an instantiated type referred to
+ // by an alias (which cannot have receiver parameters for now).
+ if T.TypeArgs() != nil && sig.RecvTypeParams() == nil {
+ check.errorf(recv, InvalidRecv, "cannot define new methods on instantiated type %s", rtyp)
+ break
+ }
if T.obj.pkg != check.pkg {
- err = "type not defined in this package"
- if check.conf.CompilerErrorMessages {
- check.errorf(recv.pos, "cannot define new methods on non-local type %s", recv.typ)
- err = ""
+ check.errorf(recv, InvalidRecv, "cannot define new methods on non-local type %s", rtyp)
+ break
+ }
+ var cause string
+ switch u := T.under().(type) {
+ case *Basic:
+ // unsafe.Pointer is treated like a regular pointer
+ if u.kind == UnsafePointer {
+ cause = "unsafe.Pointer"
}
- } else {
- // The underlying type of a receiver base type can be a type parameter;
- // e.g. for methods with a generic receiver T[P] with type T[P any] P.
- underIs(T, func(u Type) bool {
- switch u := u.(type) {
- case *Basic:
- // unsafe.Pointer is treated like a regular pointer
- if u.kind == UnsafePointer {
- err = "unsafe.Pointer"
- return false
- }
- case *Pointer, *Interface:
- err = "pointer or interface type"
- return false
- }
- return true
- })
+ case *Pointer, *Interface:
+ cause = "pointer or interface type"
+ case *TypeParam:
+ // The underlying type of a receiver base type cannot be a
+ // type parameter: "type T[P any] P" is not a valid declaration.
+ unreachable()
}
- case *Basic:
- err = "basic or unnamed type"
- if check.conf.CompilerErrorMessages {
- check.errorf(recv.pos, "cannot define new methods on non-local type %s", recv.typ)
- err = ""
+ if cause != "" {
+ check.errorf(recv, InvalidRecv, "invalid receiver type %s (%s)", rtyp, cause)
}
+ case *Basic:
+ check.errorf(recv, InvalidRecv, "cannot define new methods on non-local type %s", rtyp)
default:
- check.errorf(recv.pos, "invalid receiver type %s", recv.typ)
- }
- if err != "" {
- check.errorf(recv.pos, "invalid receiver type %s (%s)", recv.typ, err)
- // ok to continue
+ check.errorf(recv, InvalidRecv, "invalid receiver type %s", recv.typ)
}
- }
- sig.recv = recv
+ }).describef(recv, "validate receiver %s", recv)
}
sig.params = NewTuple(params...)
}
// 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 []*syntax.Field, type0 syntax.Expr, variadicOk bool) (params []*Var, variadic bool) {
+// variable list.
+func (check *Checker) collectParams(scope *Scope, list []*syntax.Field, variadicOk bool) (params []*Var, variadic bool) {
if list == nil {
return
}
// type-check type of grouped fields only once
if ftype != prev {
prev = ftype
- if i == 0 && type0 != nil {
- ftype = type0
- }
if t, _ := ftype.(*syntax.DotsType); t != nil {
ftype = t.Elem
if variadicOk && i == len(list)-1 {
variadic = true
} else {
- check.softErrorf(t, "can only use ... with final parameter in list")
+ check.softErrorf(t, MisplacedDotDotDot, "can only use ... with final parameter in list")
// ignore ... and continue
}
}
// named parameter
name := field.Name.Value
if name == "" {
- check.error(field.Name, invalidAST+"anonymous parameter")
+ check.error(field.Name, InvalidSyntaxTree, "anonymous parameter")
// ok to continue
}
par := NewParam(field.Name.Pos(), check.pkg, name, typ)
}
if named && anonymous {
- check.error(list[0], invalidAST+"list contains both named and anonymous parameters")
+ check.error(list[0], InvalidSyntaxTree, "list contains both named and anonymous parameters")
// ok to continue
}
return
}
-
-// isubst returns an x with identifiers substituted per the substitution map smap.
-// isubst only handles the case of (valid) method receiver type expressions correctly.
-func isubst(x syntax.Expr, smap map[*syntax.Name]*syntax.Name) syntax.Expr {
- switch n := x.(type) {
- case *syntax.Name:
- if alt := smap[n]; alt != nil {
- return alt
- }
- // case *syntax.StarExpr:
- // X := isubst(n.X, smap)
- // if X != n.X {
- // new := *n
- // new.X = X
- // return &new
- // }
- case *syntax.Operation:
- if n.Op == syntax.Mul && n.Y == nil {
- X := isubst(n.X, smap)
- if X != n.X {
- new := *n
- new.X = X
- return &new
- }
- }
- case *syntax.IndexExpr:
- Index := isubst(n.Index, smap)
- if Index != n.Index {
- new := *n
- new.Index = Index
- return &new
- }
- case *syntax.ListExpr:
- var elems []syntax.Expr
- for i, elem := range n.ElemList {
- new := isubst(elem, smap)
- if new != elem {
- if elems == nil {
- elems = make([]syntax.Expr, len(n.ElemList))
- copy(elems, n.ElemList)
- }
- elems[i] = new
- }
- }
- if elems != nil {
- new := *n
- new.ElemList = elems
- return &new
- }
- case *syntax.ParenExpr:
- return isubst(n.X, smap) // no need to keep parentheses
- default:
- // Other receiver type expressions are invalid.
- // It's fine to ignore those here as they will
- // be checked elsewhere.
- }
- return x
-}