The following example:

  1 doit() {
  2 error(error) {
  3 print(error);
  4 }
  5 error('foobar');
  6 }
  7 main() {
  8 doit();
  9 }

Results in the following output of dartanalyzer/dart2js/dartvm:

$ dartanalyzer test.dart
Analyzing [test.dart]...
[error] The name 'error' is already defined (/usr/local/google/home/kustermann/test.dart, line 2, col 9)
1 error found.

$ dart2js --out=/tmp/foo.js test.dart
test.dart:2:3:
Error: Duplicate definition of 'error(error){print(error);}'.
  error(error) {
  ^^^^^
test.dart:2:9:
Info: Existing definition of 'error(error){print(error);}'.
  error(error) {
        ^^^^^
Error: Compilation failed.

$ dart test.dart
foobar

Dart-SDK version: 1.6.0-dev.3.0

lrn/ahe/I think that this is a bug in dartanalyzer/dart2js.