Instantiate enclosing elements for anonymous functions (#1841)

* Instantiate enclosing elements for anonymous functions, even when they're not directly attached to libraries

* Add test

* Update test package docs

Author: jcollins-g

lib/src/model.dart

@@ -3877,8 +3877,8 @@ abstract class ModelElement extends Canonicalization
       return fqName;
     }
 
-    ModelElement parent = (e as EnclosedElement).enclosingElement;
-    return _buildFullyQualifiedName(parent, '${parent.name}.$fqName');
+    return _buildFullyQualifiedName(
+        e.enclosingElement, '${e.enclosingElement.name}.$fqName');
   }
 
   String _calculateLinkedName() {
@@ -4455,6 +4455,13 @@ class ModelFunctionAnonymous extends ModelFunctionTyped {
       FunctionTypedElement element, PackageGraph packageGraph)
       : super(element, null, packageGraph) {}
 
+  @override
+  ModelElement get enclosingElement {
+    // These are not considered to be a part of libraries, so we can simply
+    // blindly instantiate a ModelElement for their enclosing element.
+    return new ModelElement.fromElement(element.enclosingElement, packageGraph);
+  }
+
   @override
   String get name => 'Function';
 
@@ -6040,7 +6047,9 @@ class Package extends LibraryContainer
 
   /// Is this the package at the top of the list?  We display the first
   /// package specially (with "Libraries" rather than the package name).
-  bool get isFirstPackage => packageGraph.localPackages.isNotEmpty && identical(packageGraph.localPackages.first, this);
+  bool get isFirstPackage =>
+      packageGraph.localPackages.isNotEmpty &&
+      identical(packageGraph.localPackages.first, this);
 
   @override
   bool get isSdk => packageMeta.isSdk;

test/model_test.dart

@@ -3208,6 +3208,7 @@ String topLevelFunction(int param1, bool param2, Cool coolBeans,
         paramFromExportLib,
         methodWithTypedefParam,
         applyCovariantParams;
+    ModelFunction doAComplicatedThing;
     Parameter intNumber, intCheckOptional;
 
     setUpAll(() {
@@ -3231,6 +3232,8 @@ String topLevelFunction(int param1, bool param2, Cool coolBeans,
           .singleWhere((m) => m.name == 'methodWithGenericParam');
       methodWithTypedefParam = c.instanceMethods
           .singleWhere((m) => m.name == 'methodWithTypedefParam');
+      doAComplicatedThing = fakeLibrary.publicFunctions
+          .firstWhere((m) => m.name == 'doAComplicatedThing');
     });
 
     test('covariant parameters render correctly', () {
@@ -3239,6 +3242,13 @@ String topLevelFunction(int param1, bool param2, Cool coolBeans,
           contains('<span>covariant</span>'));
     });
 
+    test(
+        'ambiguous reference to function parameter parameters resolves to nothing',
+        () {
+      expect(doAComplicatedThing.documentationAsHtml,
+          contains('<code>aThingParameter</code>'));
+    });
+
     test('has parameters', () {
       expect(isGreaterThan.parameters, hasLength(2));
     });

testing/test_package/lib/fake.dart

@@ -97,6 +97,14 @@ class HasGenerics<X, Y, Z> {
   Map<X, Y> convertToMap() => null;
 }
 
+/// Coderef to ambiguous parameter of function parameter should not crash us.
+/// (#1835)
+///
+/// Here is a coderef: [aThingParameter]
+void doAComplicatedThing(int x,
+    {void doSomething(int aThingParameter, String anotherThing),
+    void doSomethingElse(int aThingParameter, double somethingElse)}) {}
+
 /// Bullet point documentation.
 ///
 /// This top level constant has bullet points.