[nnbd_migration] Add an edge origin for type name parameters.

MichaelRFairhurst · commit-bot@chromium.org · commit 734ad9c00c49 · 2020-02-28T23:26:22.000Z
Change-Id: Ifad0a0ae6e641360ac5be5eea5c61e667be33cbc Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/137432 Reviewed-by: Paul Berry <paulberry@google.com>
diff --git a/pkg/nnbd_migration/lib/instrumentation.dart b/pkg/nnbd_migration/lib/instrumentation.dart
@@ -157,6 +157,7 @@ enum EdgeOriginKind {
   thisOrSuper,
   throw_,
   typedefReference,
+  typeParameterInstantiation,
   uninitializedRead,
 }
 
diff --git a/pkg/nnbd_migration/lib/src/edge_builder.dart b/pkg/nnbd_migration/lib/src/edge_builder.dart
@@ -1556,8 +1556,11 @@ class EdgeBuilder extends GeneralizingAstVisitor<DecoratedType>
             _unimplemented(typeName,
                 'No decorated type for type argument ${typeArguments[i]} ($i)');
           }
-          _checkAssignment(null,
-              source: argumentType, destination: bound, hard: true);
+          _checkAssignment(
+              TypeParameterInstantiationOrigin(source, typeArguments[i]),
+              source: argumentType,
+              destination: bound,
+              hard: true);
         }
       }
     }
diff --git a/pkg/nnbd_migration/lib/src/edge_origin.dart b/pkg/nnbd_migration/lib/src/edge_origin.dart
@@ -421,6 +421,19 @@ class TypedefReferenceOrigin extends EdgeOrigin {
   EdgeOriginKind get kind => EdgeOriginKind.typedefReference;
 }
 
+/// Edge origin resulting from the instantiation of a type parameter, which
+/// affects the nullability of that type parameter's bound.
+class TypeParameterInstantiationOrigin extends EdgeOrigin {
+  TypeParameterInstantiationOrigin(Source source, TypeAnnotation node)
+      : super(source, node);
+
+  @override
+  EdgeOriginKind get kind => EdgeOriginKind.typeParameterInstantiation;
+
+  @override
+  TypeAnnotation get node => super.node as TypeAnnotation;
+}
+
 /// Edge origin resulting from the read of a variable that has not been
 /// definitely assigned a value.
 class UninitializedReadOrigin extends EdgeOrigin {

Original file line number	Diff line number	Diff line change
`@@ -157,6 +157,7 @@ enum EdgeOriginKind {`
`157`	`157`	`thisOrSuper,`
`158`	`158`	`throw_,`
`159`	`159`	`typedefReference,`
	`160`	`+ typeParameterInstantiation,`
`160`	`161`	`uninitializedRead,`
`161`	`162`	`}`
`162`	`163`
Original file line number	Diff line number	Diff line change
`@@ -1556,8 +1556,11 @@ class EdgeBuilder extends GeneralizingAstVisitor<DecoratedType>`
`1556`	`1556`	`_unimplemented(typeName,`
`1557`	`1557`	`'No decorated type for type argument ${typeArguments[i]} ($i)');`
`1558`	`1558`	`}`
`1559`		`- _checkAssignment(null,`
`1560`		`- source: argumentType, destination: bound, hard: true);`
	`1559`	`+ _checkAssignment(`
	`1560`	`+ TypeParameterInstantiationOrigin(source, typeArguments[i]),`
	`1561`	`+ source: argumentType,`
	`1562`	`+ destination: bound,`
	`1563`	`+ hard: true);`
`1561`	`1564`	`}`
`1562`	`1565`	`}`
`1563`	`1566`	`}`