Fix _inferSetOrMapLiteralType to handle a context of `?` correctly.
Also add a comment explaining why it's not necessary to compute the
greatest closure (even though the spec says to do so).
Change-Id: I74f78ca3b6d43fedfaefb13f9120248eb62b283b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/96142
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
diff --git a/pkg/analyzer/lib/src/generated/static_type_analyzer.dart b/pkg/analyzer/lib/src/generated/static_type_analyzer.dart
index da50a41..2c842f4 100644
--- a/pkg/analyzer/lib/src/generated/static_type_analyzer.dart
+++ b/pkg/analyzer/lib/src/generated/static_type_analyzer.dart
@@ -1774,11 +1774,17 @@
} else if (canBeAMap && mustBeAMap) {
return _toMapType(literal, contextType, inferredTypes);
}
- // TODO(paulberry): the following computations should be based on the
- // greatest closure of the context type.
- bool contextIsIterable = contextType != null &&
+ // Note: according to the spec, the following computations should be based
+ // on the greatest closure of the context type (unless the context type is
+ // `?`). In practice, we can just use the context type directly, because
+ // the only way the greatest closure of the context type could possibly have
+ // a different subtype relationship to `Iterable<Object>` and
+ // `Map<Object, Object>` is if the context type is `?`.
+ bool contextProvidesAmbiguityResolutionClues =
+ contextType != null && contextType is! UnknownInferredType;
+ bool contextIsIterable = contextProvidesAmbiguityResolutionClues &&
_typeSystem.isSubtypeOf(contextType, _typeProvider.iterableObjectType);
- bool contextIsMap = contextType != null &&
+ bool contextIsMap = contextProvidesAmbiguityResolutionClues &&
_typeSystem.isSubtypeOf(contextType, _typeProvider.mapObjectObjectType);
if (contextIsIterable && !contextIsMap) {
return _toSetType(literal, contextType, inferredTypes);
