go/parser: minor cleanup

- there is no label scope at package level
- open/close all scopes symmetrically now
  that there is only one parse entry point
  (parseFile)

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6230047

diff --git a/src/pkg/go/parser/parser.go b/src/pkg/go/parser/parser.go
index fc676de56571eac90b8957971deb5deddb6388b0..f40c4e2de3126fac141773f35c2e01bea9028bb4 100644 (file)
--- a/src/pkg/go/parser/parser.go
+++ b/src/pkg/go/parser/parser.go
@@ -56,7 +56,7 @@ type parser struct {
        unresolved []*ast.Ident      // unresolved identifiers
        imports    []*ast.ImportSpec // list of imports
 
-       // Label scope
+       // Label scopes
        // (maintained by open/close LabelScope)
        labelScope  *ast.Scope     // label scope for current function
        targetStack [][]*ast.Ident // stack of unresolved labels
@@ -75,14 +75,6 @@ func (p *parser) init(fset *token.FileSet, filename string, src []byte, mode Mod
        p.trace = mode&Trace != 0 // for convenience (p.trace is used frequently)
 
        p.next()
-
-       // set up the pkgScope here (as opposed to in parseFile) because
-       // there are other parser entry points (ParseExpr, etc.)
-       p.openScope()
-       p.pkgScope = p.topScope
-
-       // for the same reason, set up a label scope
-       p.openLabelScope()
 }
 
 // ----------------------------------------------------------------------------
@@ -2297,11 +2289,12 @@ func (p *parser) parseFile() *ast.File {
        }
        p.expectSemi()
 
-       var decls []ast.Decl
-
        // Don't bother parsing the rest if we had errors already.
        // Likely not a Go source file at all.
 
+       p.openScope()
+       p.pkgScope = p.topScope
+       var decls []ast.Decl
        if p.errors.Len() == 0 && p.mode&PackageClauseOnly == 0 {
                // import decls
                for p.tok == token.IMPORT {
@@ -2315,8 +2308,9 @@ func (p *parser) parseFile() *ast.File {
                        }
                }
        }
-
-       assert(p.topScope == p.pkgScope, "imbalanced scopes")
+       p.closeScope()
+       assert(p.topScope == nil, "unbalanced scopes")
+       assert(p.labelScope == nil, "unbalanced label scopes")
 
        // resolve global identifiers within the same file
        i := 0