gccgo: complex accepts complex value as 2nd argument

[griesemer]

The following program:

package main
const x = complex(0i, 1i)
func main() {
}

compiles, links, and runs w/o errors:

$ gccgo x.go -o x && ./x

(version: gccgo (google-gccgo-219769) 5.0.0 20150116 (experimental))

The 2nd argument 1i is a complex constant with non-zero imaginary component, it should not be accepted.

Note that:

package main
const x = complex(1, 1i)
func main() {
}

leads to an error:

$ gccgo x.go -o x && ./x
x.go:2:11: error: complex arguments must have identical types
 const x = complex(1, 1i)
           ^

which is misleading (both arguments are untyped).

Furthermore:

package main
import "fmt"
const x = complex(1i, 1i)
func main() {
   fmt.Println(x)
}

compiles, links, and runs without error, but does not print anything (not even a newline):

$ gccgo x.go -o x && ./x
$

[paranoiacblack]

This has the same root cause as #11566. Closng this as a duplicate; the test cases here will be sucked into the test case for #11566.