x/mobile: imported structs from other packages get skipped even if they're valid

[ToJen]

What version of Go are you using (go version)?

$ go version
go version go1.13.10 darwin/amd64

Does this issue reproduce with the latest release?

Yeah

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE="on"
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/user/Library/Caches/go-build"
GOENV="/Users/user/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/user/go"
GOPRIVATE=""
GOPROXY="..."
GOROOT="/usr/local/Cellar/[email protected]/1.13.10_1/libexec"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/[email protected]/1.13.10_1/libexec/pkg/tool/darwin_amd64"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/Users/user/Documents/project/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/..../T/go-build123=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

Trying to run gomobile bind -target=ios github.com/user/a on this code and it won't work even though MyStruct is valid against the type restrictions.

Folder structure

/a
|_ main.go
|_ /b
    |_ models.go

// in a/b/models.go

package b

type MyStruct struct {
  Value string
}

//////////

// in a/main.go

package a

import "github.com/user/a/b"

func NewIssue() (*b.MyStruct, error) {
 // ...
}

However the following work:

• if I change the return type of NewIssue() to (string, error) for example; or
• if I move MyStruct from folder a/b to a

What did you expect to see?

The generated header files containing definitions for my function.

What did you see instead?

// Objective-C API for talking to github.com/user/a Go package.
//   gobind -lang=objc github.com/user/a
//
// File is generated by gobind. Do not edit.

#ifndef __Issue_H__
#define __Issue_H__

@import Foundation;
#include "ref.h"
#include "Universe.objc.h"


// skipped function NewIssue with unsupported parameter or return types

#endif

[cagedmantis]

/cc @hyangah

[ToJen]

I think this may have to do with how I used gomobile bind. I now know I can use gomobile bind -target=ios pkg1 pkg2 pkg3 so it'll pick up the package that has MyStruct and compile it.