x/pkgsite: show embedded methods

[bradfitz]

Fix the cmd/godoc side of issue 

https://code.google.com/p/go/source/detail?r=f5b37c93e4c5bb2962c added some methods to
go1.txt that were always there, but neither cmd/godoc nor cmd/api (both with their own
bad embedding rules) detected.

Robert's rewrite of cmd/api to use go/types fixed cmd/api, but cmd/godoc is still broken.

This bug is about making those methods (like issue #6125 -- xml.Encoder.Reset / Available
/ etc) show up, if they're actually there.  (But issue #6125 should remove them)

[rsc]

Comment 1:

Labels changed: added go1.3maybe, removed go1.2maybe.

[rsc]

Comment 2:

Labels changed: added release-none, removed go1.3maybe.

[rsc]

Comment 3:

Labels changed: added repo-tools.

[agnivade]

Took a look at this. There are various scenarios to be considered.

• If the embedded type is not exported, the methods are shown.
• If the embedded type is exported and in same package, the methods are shown by the "Mode.AllMethods" flag.
• Only in the case where the embedded type is coming from another package, then the methods for that type is not extracted.

So in a case like this -

import "sync"

type T4 struct{}

// T4.M should appear as method of T5 only if AllMethods is set.
func (*T4) M() {}

type T5 struct {
	T4
	sync.Mutex
}

when AllMethods is set, T5 will show M(), but not Lock() and Unlock()

The relevant code is in (r *reader) recordAnonymousField() function in go/doc/reader.go. If the fieldType is imported, then it is ignored.

@griesemer - I am not very well-versed with the go/types package. Can you tell me how to get the methods for a type from another package ? Or is this a non-trivial task ?