Consider variant constructors pure functions for the purpose of purity checking

Closes #1269

Author: marijnh

src/comp/middle/typeck.rs

@@ -1477,8 +1477,9 @@ fn require_pure_call(ccx: @crate_ctxt, caller_purity: ast::purity,
       }
       ast::pure_fn. {
         alt ccx.tcx.def_map.find(callee.id) {
-          some(ast::def_fn(_, ast::pure_fn.)) { ret; }
-          some(ast::def_native_fn(_, ast::pure_fn.)) { ret; }
+          some(ast::def_fn(_, ast::pure_fn.)) |
+          some(ast::def_native_fn(_, ast::pure_fn.)) |
+          some(ast::def_variant(_, _)) { ret; }
           _ {
             ccx.tcx.sess.span_err
                 (sp, "pure function calls function not known to be pure");

src/comp/syntax/parse/lexer.rs

@@ -176,7 +176,6 @@ fn scan_exponent(rdr: reader) -> option::t<str> {
 }
 
 fn scan_digits(rdr: reader, radix: uint) -> str {
-    radix; // FIXME work around issue #1265
     let rslt = "";
     while true {
         let c = rdr.curr();