-- bug/foo.go --
package pkg

import (
	assist "example.com/bug_assist"
)

func fn(int) {}

func bar() {
	const oracle = assist.C
	fn(oracle)
}
-- bug_assist/assist.go --
package assist

const A = 0.05
const B = 10000
const C = A * B
-- go.mod --
module example.com

go 1.18

require golang.org/x/tools v0.1.11

require (
	golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4 // indirect
	golang.org/x/sys v0.0.0-20211019181941-9d821ace8654 // indirect
)
-- go.sum --
golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4 h1:6zppjxzCulZykYSLyVDYbneBfbaBIQPYMevg0bEwv2s=
golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
golang.org/x/sys v0.0.0-20211019181941-9d821ace8654 h1:id054HUawV2/6IGm2IV8KZQjqtwAOo2CYlOToYqa0d0=
golang.org/x/sys v0.0.0-20211019181941-9d821ace8654/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/tools v0.1.11 h1:loJ25fNOEhSXfHrpoGj91eCUThwdNX6u24rO1xnNteY=
golang.org/x/tools v0.1.11/go.mod h1:SgwaegtQh8clINPpECJMqnxLv9I09HLqnW3RMqW0CA4=
-- run_me.go --
package main

import (
	"fmt"
	"log"

	"golang.org/x/tools/go/packages"
)

func main() {
	cfg := &packages.Config{
		// Using LoadAllSyntax instead works fine. Seems like an issue with export data.
		Mode: packages.LoadSyntax,
	}
	pkgs, err := packages.Load(cfg, "./bug")
	if err != nil {
		log.Fatal(err)
	}
	for _, pkg := range pkgs {
		fmt.Println(pkg, pkg.Errors)
	}
}