code review 7712044: all: remove now-unnecessary unreachable panics

src/cmd/api/goapi.go

 // Copyright 2011 The Go Authors.  All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 // Api computes the exported API of a set of Go packages.
 //
 // BUG(bradfitz): Note that this tool is only currently suitable
 // for use on the Go standard library, not arbitrary packages.
 // Once the Go AST has type information, this tool will be more
 // reliable without hard-coded hacks throughout.
@@ skipping 705 matching lines @@
                 // until the Go AST has type information.
                 nodeStr := w.nodeString(v.Fun)
                 switch nodeStr {
                 case "string", "[]byte":
                         return nodeStr, nil
                 }
                 return "", fmt.Errorf("not a known function %q", nodeStr)
         default:
                 return "", fmt.Errorf("unknown const value type %T", vi)
         }
-        panic("unreachable")
 }
 
 // resolveName finds a top-level node named name and returns the node
 // v and its type t, if known.
 func (w *Walker) resolveName(name string) (v interface{}, t interface{}, ok bool) {
         for _, file := range w.curPackage.Files {
                 for _, di := range file.Decls {
                         switch d := di.(type) {
                         case *ast.GenDecl:
                                 switch d.Tok {
@@ skipping 438 matching lines @@
 }
 
 func strListContains(l []string, s string) bool {
         for _, v := range l {
                 if v == s {
                         return true
                 }
         }
         return false
 }