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empty_map_pattern

A map pattern must have at least one entry.

Description

#

The analyzer produces this diagnostic when a map pattern is empty.

Example

#

The following code produces this diagnostic because the map pattern is empty:

dart
void f(Map<int, String> x) {
  if (x case {}) {}
}

Common fixes

#

If the pattern should match any map, then replace it with an object pattern:

dart
void f(Map<int, String> x) {
  if (x case Map()) {}
}

If the pattern should only match an empty map, then check the length in the pattern:

dart
void f(Map<int, String> x) {
  if (x case Map(isEmpty: true)) {}
}