What steps will reproduce the problem?
1. Run gotype (code.google.com/p/go.exp/gotype) on:

package main

var (
      s uint = 20
      x int = complex(1<<s, 2)
)

What is the expected output? What do you see instead?

Expected: something like
truc.go:5:??: cannot assign complex(1<<s, 2) (untyped complex) to x of type int

Got: no error.

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