Fix some corner cases of inferring type parameters from bounds.

pkg/analyzer/test/src/summary/linker_test.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/summary/format.dart';
 import 'package:analyzer/src/summary/idl.dart';
 import 'package:analyzer/src/summary/link.dart';
 import 'package:unittest/unittest.dart';
@@ skipping 490 matching lines @@
         linker
             .getLibrary(linkerInputs.testDartUri)
             .getContainedName('b')
             .asTypeInferenceNode
             .variableElement
             .inferredType
             .toString(),
         'int');
   }
 
+  void test_instantiate_param_of_param_to_bounds() {
+    createLinker('''
+class C<T> {}
+class D<T extends num> {}
+final x = new C<D>();
+''');
+    LibraryElementForLink library = linker.getLibrary(linkerInputs.testDartUri);
+    library.libraryCycleForLink.ensureLinked();
+    PropertyAccessorElementForLink_Variable x = library.getContainedName('x');
+    ParameterizedType type1 = x.returnType;
+    expect(type1.element.name, 'C');
+    expect(type1.typeArguments, hasLength(1));
+    ParameterizedType type2 = type1.typeArguments[0];
+    expect(type2.element.name, 'D');
+    expect(type2.typeArguments, hasLength(1));
+    DartType type3 = type2.typeArguments[0];
+    expect(type3.toString(), 'num');
+  }
+
+  void test_instantiate_param_to_bounds_class() {
+    createLinker('''
+class C<T extends num> {}
+final x = new C();
+''');
+    LibraryElementForLink library = linker.getLibrary(linkerInputs.testDartUri);
+    library.libraryCycleForLink.ensureLinked();
+    PropertyAccessorElementForLink_Variable x = library.getContainedName('x');
+    ParameterizedType type1 = x.returnType;
+    expect(type1.element.name, 'C');
+    expect(type1.typeArguments, hasLength(1));
+    DartType type2 = type1.typeArguments[0];
+    expect(type2.toString(), 'num');
+  }
+
+  void test_instantiate_param_to_bounds_typedef() {
+    createLinker('''
+typedef T F<T extends num>();
+final x = new List<F>();
+''');
+    LibraryElementForLink library = linker.getLibrary(linkerInputs.testDartUri);
+    library.libraryCycleForLink.ensureLinked();
+    PropertyAccessorElementForLink_Variable x = library.getContainedName('x');
+    ParameterizedType type1 = x.returnType;
+    expect(type1.element.name, 'List');
+    expect(type1.typeArguments, hasLength(1));
+    FunctionType type2 = type1.typeArguments[0];
+    expect(type2.element.name, 'F');
+    expect(type2.returnType.toString(), 'num');
+  }
+
   void test_leastUpperBound_functionAndClass() {
     createLinker('''
 class C {}
 void f() {}
 var x = {
   'C': C,
   'f': f
 };
 ''');
     LibraryElementForLink library = linker.getLibrary(linkerInputs.testDartUri);
@@ skipping 246 matching lines @@
     PropertyAccessorElementForLink_Variable c = library.getContainedName('c');
     expect(c.variable.initializer, isNotNull);
     PropertyAccessorElementForLink_Variable i = library.getContainedName('i');
     expect(i.variable.initializer, isNotNull);
     PropertyAccessorElementForLink_Variable j = library.getContainedName('j');
     expect(j.variable.initializer, isNull);
     PropertyAccessorElementForLink_Variable v = library.getContainedName('v');
     expect(v.variable.initializer, isNotNull);
   }
 }