This test exercises diagnostics produced for syntax errors.

Because parser error recovery can be quite lossy, diagnostics
for type errors are suppressed in files with syntax errors;
see issue #59888. But diagnostics are reported for type errors
in well-formed files of the same package.

-- go.mod --
module example.com
go 1.12

-- bad.go --
package p

func f() {
	append("") // no diagnostic for type error in file containing syntax error
}

func .() {} //@diag(re"func ().", re"expected 'IDENT', found '.'")

-- good.go --
package p

func g() {
	append("") //@diag(re`""`, re"a slice")
}