gistfile1.txt

package main


import (
    "fmt"
    "runtime"
)

type AssertionError struct {
    pc uintptr
    file string
    line int
}


func main() {
    defer func() {
        if r := recover(); r != nil {
            err, _ := r.(*AssertionError)
            fmt.Printf("Assertion failure at: %s:%d\n", err.file, err.line)
        }
    }()

    test_func();
}

func assert(v bool) {
    if !v {
        pc, file, line, _ := runtime.Caller(1)
        fmt.Printf("%d\n", line)
        panic(&AssertionError{pc, file, line})
    }
}

func test_func() {
    assert(3 == 4)
}

For Alex... see line 19.