predeclared 
Find code that overrides one of Go's predeclared identifiers (new, make, append uint, etc.).
The list of predeclared identifiers can be found in the spec.
go get github.com/nishanths/predeclared
See godoc or run predeclared without arguments to print usage.
Test
cd passes/predeclared && go test
Examples
Given a package with the file:
package pkg // import "example.org/foo/pkg"
func copy() {}
func print() {}
func foo() string {
string := "x"
return string
}
type int struct{}running:
predeclared example.org/foo/pkg
prints:
example.go:3:6: function "copy" has same name as predeclared identifier
example.go:4:6: function "print" has same name as predeclared identifier
example.go:7:2: variable "string" has same name as predeclared identifier
example.go:11:6: type "int" has same name as predeclared identifier
Running the program on the standard library's text package and subpackages produces:
$ predeclared text/...
/usr/local/go/src/text/template/parse/node.go:554:33: param "true" has same name as predeclared identifier
/usr/local/go/src/text/template/parse/node.go:599:3: variable "rune" has same name as predeclared identifier
/usr/local/go/src/text/template/funcs.go:164:36: param "cap" has same name as predeclared identifier
/usr/local/go/src/text/template/funcs.go:233:3: variable "cap" has same name as predeclared identifier
/usr/local/go/src/text/template/template.go:218:30: param "new" has same name as predeclared identifier
/usr/local/go/src/text/template/exec_test.go:232:21: param "error" has same name as predeclared identifier