Elements. Pull implementations out of ConstructorElementMixin, leave only declarations.

ConstructorMember uses baseElement to implement, as every other method.

Change-Id: I3d6e5f16e83e6c601691cfdd0c254b861ffd9a68
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/435960
Reviewed-by: Paul Berry <paulberry@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

pkg/analyzer/lib/src/dart/element/element.dart

@@ -922,28 +922,13 @@ mixin ConstructorElementMixin
 
   /// Whether the constructor can be used as a default constructor - unnamed,
   /// and has no required parameters.
-  bool get isDefaultConstructor {
-    // unnamed
-    if (name2 != 'new') {
-      return false;
-    }
-    // no required parameters
-    for (var parameter in parameters) {
-      if (parameter.isRequired) {
-        return false;
-      }
-    }
-    // OK, can be used as default constructor
-    return true;
-  }
+  bool get isDefaultConstructor;
 
   /// Whether the constructor represents a factory constructor.
   bool get isFactory;
 
   /// Whether the constructor represents a generative constructor.
-  bool get isGenerative {
-    return !isFactory;
-  }
+  bool get isGenerative;
 
   @override
   LibraryElementImpl get library2;
@@ -1066,6 +1051,22 @@ class ConstructorFragmentImpl extends ExecutableFragmentImpl
     setModifier(Modifier.CONST, isConst);
   }
 
+  @override
+  bool get isDefaultConstructor {
+    // unnamed
+    if (name2 != 'new') {
+      return false;
+    }
+    // no required parameters
+    for (var parameter in parameters) {
+      if (parameter.isRequired) {
+        return false;
+      }
+    }
+    // OK, can be used as default constructor
+    return true;
+  }
+
   @override
   bool get isFactory {
     return hasModifier(Modifier.FACTORY);
@@ -1076,6 +1077,11 @@ class ConstructorFragmentImpl extends ExecutableFragmentImpl
     setModifier(Modifier.FACTORY, isFactory);
   }
 
+  @override
+  bool get isGenerative {
+    return !isFactory;
+  }
+
   @override
   ElementKind get kind => ElementKind.CONSTRUCTOR;
 

pkg/analyzer/lib/src/dart/element/member.dart

@@ -67,9 +67,15 @@ class ConstructorMember extends ExecutableMember
   @override
   bool get isConstantEvaluated => declaration.isConstantEvaluated;
 
+  @override
+  bool get isDefaultConstructor => baseElement.isConst;
+
   @override
   bool get isFactory => declaration.isFactory;
 
+  @override
+  bool get isGenerative => baseElement.isGenerative;
+
   @override
   LibraryElementImpl get library2 {
     return _declaration.library!;