go/*: various small fixes

parser:
- resolve embedded interface type names
ast:
- clarify some comments
- correctly unquote import paths

R=rsc
CC=golang-dev
https://golang.org/cl/4528060

src/pkg/go/ast/ast.go

@@ -121,7 +121,7 @@ func (f *Field) End() token.Pos {
 // A FieldList represents a list of Fields, enclosed by parentheses or braces.
 type FieldList struct {
 	Opening token.Pos // position of opening parenthesis/brace, if any
-	List    []*Field  // field list
+	List    []*Field  // field list; or nil
 	Closing token.Pos // position of closing parenthesis/brace, if any
 }
 
@@ -334,7 +334,7 @@ type (
 	// A FuncType node represents a function type.
 	FuncType struct {
 		Func    token.Pos  // position of "func" keyword
-		Params  *FieldList // (incoming) parameters
+		Params  *FieldList // (incoming) parameters; or nil
 		Results *FieldList // (outgoing) results; or nil
 	}
 
@@ -946,8 +946,8 @@ func (f *File) End() token.Pos {
 //
 type Package struct {
 	Name    string            // package name
-	Scope   *Scope            // package scope
-	Imports map[string]*Scope // map of import path -> package scope across all files
+	Scope   *Scope            // package scope across all files
+	Imports map[string]*Scope // map of import path -> package scope
 	Files   map[string]*File  // Go source files by filename
 }
 

src/pkg/go/ast/resolve.go

@@ -11,6 +11,7 @@ import (
 	"go/scanner"
 	"go/token"
 	"os"
+	"strconv"
 )
 
 
@@ -70,7 +71,7 @@ type Importer func(path string) (name string, scope *Scope, err os.Error)
 // used to resolve identifiers not declared in any of the package files. Any
 // remaining unresolved identifiers are reported as undeclared. If the files
 // belong to different packages, one package name is selected and files with
-// different package name are reported and then ignored.
+// different package names are reported and then ignored.
 // The result is a package node and a scanner.ErrorList if there were errors.
 //
 func NewPackage(fset *token.FileSet, files map[string]*File, importer Importer, universe *Scope) (*Package, os.Error) {
@@ -118,8 +119,7 @@ func NewPackage(fset *token.FileSet, files map[string]*File, importer Importer,
 		fileScope := NewScope(pkgScope)
 		for _, spec := range file.Imports {
 			// add import to global map of imports
-			path := string(spec.Path.Value)
-			path = path[1 : len(path)-1] // strip ""'s
+			path, _ := strconv.Unquote(string(spec.Path.Value))
 			pkg := imports[path]
 			if pkg == nil {
 				if importer == nil {
@@ -161,8 +161,8 @@ func NewPackage(fset *token.FileSet, files map[string]*File, importer Importer,
 		if importErrors {
 			// don't use the universe scope without correct imports
 			// (objects in the universe may be shadowed by imports;
-			// with missing imports identifiers might get resolved
-			// wrongly)
+			// with missing imports, identifiers might get resolved
+			// incorrectly to universe objects)
 			pkgScope.Outer = nil
 		}
 		i := 0

src/pkg/go/parser/parser.go

@@ -818,6 +818,7 @@ func (p *parser) parseMethodSpec(scope *ast.Scope) *ast.Field {
 	} else {
 		// embedded interface
 		typ = x
+		p.resolve(typ)
 	}
 	p.expectSemi() // call before accessing p.linecomment