]> Cypherpunks.ru repositories - gostls13.git/blobdiff - src/go/types/resolver.go
go/types, types2: introduce _Alias type node
[gostls13.git] / src / go / types / resolver.go
index 7c7a68b01c4a605daff26b48def43853562a3626..8b6a1b4b79e0717021a114ab7484aaf021817acd 100644 (file)
@@ -63,7 +63,7 @@ func (check *Checker) arityMatch(s, init *ast.ValueSpec) {
        case init == nil && r == 0:
                // var decl w/o init expr
                if s.Type == nil {
-                       check.errorf(s, code, "missing type or init expr")
+                       check.error(s, code, "missing type or init expr")
                }
        case l < r:
                if l < len(s.Values) {
@@ -107,18 +107,18 @@ func (check *Checker) declarePkgObj(ident *ast.Ident, obj Object, d *declInfo) {
        // spec: "A package-scope or file-scope identifier with name init
        // may only be declared to be a function with this (func()) signature."
        if ident.Name == "init" {
-               check.errorf(ident, InvalidInitDecl, "cannot declare init - must be func")
+               check.error(ident, InvalidInitDecl, "cannot declare init - must be func")
                return
        }
 
        // spec: "The main package must have package name main and declare
        // a function main that takes no arguments and returns no value."
        if ident.Name == "main" && check.pkg.name == "main" {
-               check.errorf(ident, InvalidMainDecl, "cannot declare main - must be func")
+               check.error(ident, InvalidMainDecl, "cannot declare main - must be func")
                return
        }
 
-       check.declare(check.pkg.scope, ident, obj, token.NoPos)
+       check.declare(check.pkg.scope, ident, obj, nopos)
        check.objMap[obj] = d
        obj.setOrder(uint32(len(check.objMap)))
 }
@@ -242,7 +242,7 @@ func (check *Checker) collectObjects() {
                if f := check.fset.File(file.Pos()); f != nil {
                        pos, end = token.Pos(f.Base()), token.Pos(f.Base()+f.Size())
                }
-               fileScope := NewScope(check.pkg.scope, pos, end, check.filename(fileNo))
+               fileScope := NewScope(pkg.scope, pos, end, check.filename(fileNo))
                fileScopes = append(fileScopes, fileScope)
                check.recordScope(file, fileScope)
 
@@ -275,13 +275,13 @@ func (check *Checker) collectObjects() {
                                        name = d.spec.Name.Name
                                        if path == "C" {
                                                // match 1.17 cmd/compile (not prescribed by spec)
-                                               check.errorf(d.spec.Name, ImportCRenamed, `cannot rename import "C"`)
+                                               check.error(d.spec.Name, ImportCRenamed, `cannot rename import "C"`)
                                                return
                                        }
                                }
 
                                if name == "init" {
-                                       check.errorf(d.spec, InvalidInitDecl, "cannot import package as init - init must be a func")
+                                       check.error(d.spec, InvalidInitDecl, "cannot import package as init - init must be a func")
                                        return
                                }
 
@@ -325,7 +325,7 @@ func (check *Checker) collectObjects() {
                                                        // (Do not use check.declare because it modifies the object
                                                        // via Object.setScopePos, which leads to a race condition;
                                                        // the object may be imported into more than one file scope
-                                                       // concurrently. See issue #32154.)
+                                                       // concurrently. See go.dev/issue/32154.)
                                                        if alt := fileScope.Lookup(name); alt != nil {
                                                                check.errorf(d.spec.Name, DuplicateDecl, "%s redeclared in this block", alt.Name())
                                                                check.reportAltDecl(alt)
@@ -338,7 +338,7 @@ func (check *Checker) collectObjects() {
                                } else {
                                        // declare imported package object in file scope
                                        // (no need to provide s.Name since we called check.recordDef earlier)
-                                       check.declare(fileScope, nil, pkgName, token.NoPos)
+                                       check.declare(fileScope, nil, pkgName, nopos)
                                }
                        case constDecl:
                                // declare all constants
@@ -386,9 +386,7 @@ func (check *Checker) collectObjects() {
                                        check.declarePkgObj(name, obj, di)
                                }
                        case typeDecl:
-                               if d.spec.TypeParams.NumFields() != 0 && !check.allowVersion(pkg, 1, 18) {
-                                       check.softErrorf(d.spec.TypeParams.List[0], UnsupportedFeature, "type parameter requires go1.18 or later")
-                               }
+                               _ = d.spec.TypeParams.NumFields() != 0 && check.verifyVersionf(d.spec.TypeParams.List[0], go1_18, "type parameter")
                                obj := NewTypeName(d.spec.Name.Pos(), pkg, d.spec.Name.Name, nil)
                                check.declarePkgObj(d.spec.Name, obj, &declInfo{file: fileScope, tdecl: d.spec})
                        case funcDecl:
@@ -425,7 +423,7 @@ func (check *Checker) collectObjects() {
                                                        check.softErrorf(obj, MissingInitBody, "missing function body")
                                                }
                                        } else {
-                                               check.declare(pkg.scope, d.decl.Name, obj, token.NoPos)
+                                               check.declare(pkg.scope, d.decl.Name, obj, nopos)
                                        }
                                } else {
                                        // method
@@ -444,9 +442,7 @@ func (check *Checker) collectObjects() {
                                        }
                                        check.recordDef(d.decl.Name, obj)
                                }
-                               if d.decl.Type.TypeParams.NumFields() != 0 && !check.allowVersion(pkg, 1, 18) && !hasTParamError {
-                                       check.softErrorf(d.decl.Type.TypeParams.List[0], UnsupportedFeature, "type parameter requires go1.18 or later")
-                               }
+                               _ = d.decl.Type.TypeParams.NumFields() != 0 && !hasTParamError && check.verifyVersionf(d.decl.Type.TypeParams.List[0], go1_18, "type parameter")
                                info := &declInfo{file: fileScope, fdecl: d.decl}
                                // Methods are not package-level objects but we still track them in the
                                // object map so that we can handle them like regular functions (if the
@@ -486,7 +482,7 @@ func (check *Checker) collectObjects() {
        for i := range methods {
                m := &methods[i]
                // Determine the receiver base type and associate m with it.
-               ptr, base := check.resolveBaseTypeName(m.ptr, m.recv)
+               ptr, base := check.resolveBaseTypeName(m.ptr, m.recv, fileScopes)
                if base != nil {
                        m.obj.hasPtrRecv_ = ptr
                        check.methods[base] = append(check.methods[base], m.obj)
@@ -530,7 +526,7 @@ L: // unpack receiver type
                                case *ast.BadExpr:
                                        // ignore - error already reported by parser
                                case nil:
-                                       check.errorf(ix.Orig, InvalidSyntaxTree, invalidAST+"parameterized receiver contains nil parameters")
+                                       check.error(ix.Orig, InvalidSyntaxTree, "parameterized receiver contains nil parameters")
                                default:
                                        check.errorf(arg, BadDecl, "receiver type parameter %s must be an identifier", arg)
                                }
@@ -554,7 +550,7 @@ L: // unpack receiver type
 // there was a pointer indirection to get to it. The base type name must be declared
 // in package scope, and there can be at most one pointer indirection. If no such type
 // name exists, the returned base is nil.
-func (check *Checker) resolveBaseTypeName(seenPtr bool, name *ast.Ident) (ptr bool, base *TypeName) {
+func (check *Checker) resolveBaseTypeName(seenPtr bool, typ ast.Expr, fileScopes []*Scope) (ptr bool, base *TypeName) {
        // Algorithm: Starting from a type expression, which may be a name,
        // we follow that type through alias declarations until we reach a
        // non-alias type name. If we encounter anything but pointer types or
@@ -562,8 +558,9 @@ func (check *Checker) resolveBaseTypeName(seenPtr bool, name *ast.Ident) (ptr bo
        // we're done.
        ptr = seenPtr
        var seen map[*TypeName]bool
-       var typ ast.Expr = name
        for {
+               // Note: this differs from types2, but is necessary. The syntax parser
+               // strips unnecessary parens.
                typ = unparen(typ)
 
                // check if we have a pointer type
@@ -576,15 +573,43 @@ func (check *Checker) resolveBaseTypeName(seenPtr bool, name *ast.Ident) (ptr bo
                        typ = unparen(pexpr.X) // continue with pointer base type
                }
 
-               // typ must be a name
-               name, _ := typ.(*ast.Ident)
-               if name == nil {
+               // typ must be a name, or a C.name cgo selector.
+               var name string
+               switch typ := typ.(type) {
+               case *ast.Ident:
+                       name = typ.Name
+               case *ast.SelectorExpr:
+                       // C.struct_foo is a valid type name for packages using cgo.
+                       //
+                       // Detect this case, and adjust name so that the correct TypeName is
+                       // resolved below.
+                       if ident, _ := typ.X.(*ast.Ident); ident != nil && ident.Name == "C" {
+                               // Check whether "C" actually resolves to an import of "C", by looking
+                               // in the appropriate file scope.
+                               var obj Object
+                               for _, scope := range fileScopes {
+                                       if scope.Contains(ident.Pos()) {
+                                               obj = scope.Lookup(ident.Name)
+                                       }
+                               }
+                               // If Config.go115UsesCgo is set, the typechecker will resolve Cgo
+                               // selectors to their cgo name. We must do the same here.
+                               if pname, _ := obj.(*PkgName); pname != nil {
+                                       if pname.imported.cgo { // only set if Config.go115UsesCgo is set
+                                               name = "_Ctype_" + typ.Sel.Name
+                                       }
+                               }
+                       }
+                       if name == "" {
+                               return false, nil
+                       }
+               default:
                        return false, nil
                }
 
                // name must denote an object found in the current package scope
                // (note that dot-imported objects are not in the package scope!)
-               obj := check.pkg.scope.Lookup(name.Name)
+               obj := check.pkg.scope.Lookup(name)
                if obj == nil {
                        return false, nil
                }
@@ -634,32 +659,39 @@ func (check *Checker) packageObjects() {
                }
        }
 
-       // We process non-alias type declarations first, followed by alias declarations,
-       // and then everything else. This appears to avoid most situations where the type
-       // of an alias is needed before it is available.
-       // There may still be cases where this is not good enough (see also issue #25838).
-       // In those cases Checker.ident will report an error ("invalid use of type alias").
-       var aliasList []*TypeName
-       var othersList []Object // everything that's not a type
-       // phase 1: non-alias type declarations
-       for _, obj := range objList {
-               if tname, _ := obj.(*TypeName); tname != nil {
-                       if check.objMap[tname].tdecl.Assign.IsValid() {
-                               aliasList = append(aliasList, tname)
+       if check.conf._EnableAlias {
+               // With _Alias nodes we can process declarations in any order.
+               for _, obj := range objList {
+                       check.objDecl(obj, nil)
+               }
+       } else {
+               // Without _Alias nodes, we process non-alias type declarations first, followed by
+               // alias declarations, and then everything else. This appears to avoid most situations
+               // where the type of an alias is needed before it is available.
+               // There may still be cases where this is not good enough (see also go.dev/issue/25838).
+               // In those cases Checker.ident will report an error ("invalid use of type alias").
+               var aliasList []*TypeName
+               var othersList []Object // everything that's not a type
+               // phase 1: non-alias type declarations
+               for _, obj := range objList {
+                       if tname, _ := obj.(*TypeName); tname != nil {
+                               if check.objMap[tname].tdecl.Assign.IsValid() {
+                                       aliasList = append(aliasList, tname)
+                               } else {
+                                       check.objDecl(obj, nil)
+                               }
                        } else {
-                               check.objDecl(obj, nil)
+                               othersList = append(othersList, obj)
                        }
-               } else {
-                       othersList = append(othersList, obj)
                }
-       }
-       // phase 2: alias type declarations
-       for _, obj := range aliasList {
-               check.objDecl(obj, nil)
-       }
-       // phase 3: all other declarations
-       for _, obj := range othersList {
-               check.objDecl(obj, nil)
+               // phase 2: alias type declarations
+               for _, obj := range aliasList {
+                       check.objDecl(obj, nil)
+               }
+               // phase 3: all other declarations
+               for _, obj := range othersList {
+                       check.objDecl(obj, nil)
+               }
        }
 
        // At this point we may have a non-empty check.methods map; this means that not all