Issue 28862. Implement type inference for invokeConstructor.

pkg/analyzer/lib/src/summary/link.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.
 
 /**
  * This library is capable of producing linked summaries from unlinked
  * ones (or prelinked ones).  It functions by building a miniature
  * element model to represent the contents of the summaries, and then
  * scanning the element model to gather linked information and adding
  * it to the summary data structures.
@@ skipping 49 matching lines @@
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart' show TokenType;
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/constant/value.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/type.dart';
 import 'package:analyzer/src/dart/resolver/inheritance_manager.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/resolver.dart';
+import 'package:analyzer/src/generated/static_type_analyzer.dart';
 import 'package:analyzer/src/generated/utilities_dart.dart';
 import 'package:analyzer/src/summary/format.dart';
 import 'package:analyzer/src/summary/idl.dart';
 import 'package:analyzer/src/summary/prelink.dart';
 import 'package:analyzer/src/task/strong_mode.dart';
 import 'package:front_end/src/dependency_walker.dart';
 
 bool isIncrementOrDecrement(UnlinkedExprAssignOperator operator) {
   switch (operator) {
     case UnlinkedExprAssignOperator.prefixDecrement:
@@ skipping 1593 matching lines @@
     }
   }
 
   @override
   ConstructorElementForLink get asConstructor => this;
 
   @override
   ClassElementImpl get enclosingElement => super.enclosingClass;
 
   @override
+  String get identifier => name;
+
+  @override
   bool get isCycleFree {
     if (!_constNode.isEvaluated) {
       new ConstDependencyWalker().walk(_constNode);
     }
     return _constNode.isCycleFree;
   }
 
+  @override
+  DartType get returnType => enclosingElement.type;
+
+  @override
+  List<TypeParameterElement> get typeParameters => const [];
+
   /**
    * Perform const cycle detection on this constructor.
    */
   void link(CompilationUnitElementInBuildUnit compilationUnit) {
     if (_constNode != null && !isCycleFree) {
       compilationUnit._storeConstCycle(_unlinkedExecutable.constCycleSlot);
     }
     // TODO(paulberry): call super.
   }
 
@@ skipping 614 matching lines @@
 
   void _doIfNull() {
     DartType secondType = stack.removeLast();
     DartType firstType = stack.removeLast();
     DartType type = _leastUpperBound(firstType, secondType);
     type = _dynamicIfNull(type);
     stack.add(type);
   }
 
   void _doInvokeConstructor() {
-    int numNamed = _getNextInt();
-    int numPositional = _getNextInt();
-    // TODO(paulberry): don't just pop the args; use their types
-    // to infer the type of type arguments.
-    stack.length -= numNamed + numPositional;
-    strPtr += numNamed;
+    int numNamed = unlinkedConst.ints[intPtr++];
+    int numPositional = unlinkedConst.ints[intPtr++];
+    List<String> namedArgNames = _getNextStrings(numNamed);
+    List<DartType> namedArgTypeList = _popList(numNamed);
+    List<DartType> positionalArgTypes = _popList(numPositional);
+
     EntityRef ref = _getNextRef();
-    ClassElementForLink_Class element =
-        unit.resolveConstructorClassRef(ref.reference).asClass;
-    if (element != null) {
-      stack.add(element.buildType((int i) {
-        // Type argument explicitly specified.
-        if (i < ref.typeArguments.length) {
-          return unit.resolveTypeRef(
-              ref.typeArguments[i], function.typeParameterContext);
+    ReferenceableElementForLink refElement = unit.resolveRef(ref.reference);
+    ConstructorElementForLink constructorElement = refElement.asConstructor;
+
+    if (constructorElement != null) {
+      stack.add(() {
+        if (ref.typeArguments.isNotEmpty) {
+          return constructorElement.enclosingClass.buildType((int i) {
+            if (i < ref.typeArguments.length) {
+              return unit.resolveTypeRef(
+                  ref.typeArguments[i], function.typeParameterContext);
+            } else {
+              return null;
+            }
+          }, const <int>[]);
         } else {
-          return null;
+          FunctionType rawType = StaticTypeAnalyzer
+              .constructorToGenericFunctionType(constructorElement);
+          FunctionType inferredType = _inferExecutableType(
+              rawType,
+              numNamed,
+              numPositional,
+              namedArgNames,
+              namedArgTypeList,
+              positionalArgTypes, const <DartType>[]);
+          if (identical(inferredType, rawType)) {
+            inferredType = linker.typeSystem.instantiateToBounds(rawType);
+          }
+          return inferredType.returnType;
         }
-      }, const []));
+      }());
     } else {
-      stack.add(DynamicTypeImpl.instance);
+      ClassElementForLink classElement =
+          unit.resolveConstructorClassRef(ref.reference).asClass;
+      stack.add(classElement?.type ?? DynamicTypeImpl.instance);
     }
   }
 
   void _doInvokeMethod() {
     int numNamed = unlinkedConst.ints[intPtr++];
     int numPositional = unlinkedConst.ints[intPtr++];
     List<String> namedArgNames = _getNextStrings(numNamed);
     List<DartType> namedArgTypeList = _popList(numNamed);
     List<DartType> positionalArgTypes = _popList(numPositional);
     // TODO(scheglov) if we pushed target and method name first, we might be
@@ skipping 2671 matching lines @@
    * there are no type parameters in scope.
    */
   TypeParameterizedElementMixin get _typeParameterContext;
 
   @override
   noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
 
   @override
   String toString() => '$enclosingElement.$name';
 }