[cfe] Make MethodInvocation, PropertyGet, PropertySet, IndexGet and IndexSet null-aware

This embeds the handling of null-aware access into the regular internal nodes. This also avoids some of the lowerings performed during body building.

This removes the now unused NullAwarePropertyGet and NullAwarePropertySet. NullAwareMethodInvocation will be removed latter because it is still used in other lowerings.

Change-Id: I88f3d67919cc9dadf9d16dcef4a474de90780260
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/445940
Reviewed-by: Chloe Stefantsova <[email protected]>
Commit-Queue: Johnni Winther <[email protected]>

Author: johnniwinther

pkg/front_end/lib/src/kernel/body_builder.dart

@@ -6546,7 +6546,8 @@ class BodyBuilder extends StackListenerImpl
                 allowPotentiallyConstantType: true));
       }
       return forest.createMethodInvocation(invocationOffset, receiver,
-          new Name(constructorName, libraryBuilder.nameOrigin), arguments);
+          new Name(constructorName, libraryBuilder.nameOrigin), arguments,
+          isNullAware: false);
     } else {
       if (typeArguments != null) {
         assert(forest.argumentsTypeArguments(arguments).isEmpty);
@@ -9534,20 +9535,8 @@ class BodyBuilder extends StackListenerImpl
           offset,
           name.text.length);
     }
-    if (isNullAware) {
-      VariableDeclarationImpl variable =
-          createVariableDeclarationForValue(receiver);
-      return new NullAwareMethodInvocation(
-          variable,
-          forest.createMethodInvocation(
-              offset,
-              createVariableGet(variable, receiver.fileOffset),
-              name,
-              arguments))
-        ..fileOffset = receiver.fileOffset;
-    } else {
-      return forest.createMethodInvocation(offset, receiver, name, arguments);
-    }
+    return forest.createMethodInvocation(offset, receiver, name, arguments,
+        isNullAware: isNullAware);
   }
 
   @override

pkg/front_end/lib/src/kernel/expression_generator.dart

@@ -510,13 +510,14 @@ class PropertyAccessGenerator extends Generator {
 
   @override
   Expression buildSimpleRead() {
-    return _forest.createPropertyGet(fileOffset, receiver, name);
+    return _forest.createPropertyGet(fileOffset, receiver, name,
+        isNullAware: false);
   }
 
   @override
   Expression buildAssignment(Expression value, {bool voidContext = false}) {
     return _helper.forest.createPropertySet(fileOffset, receiver, name, value,
-        forEffect: voidContext);
+        forEffect: voidContext, isNullAware: false);
   }
 
   @override
@@ -553,7 +554,8 @@ class PropertyAccessGenerator extends Generator {
         _helper.createVariableDeclarationForValue(receiver);
     VariableDeclarationImpl read = _helper.createVariableDeclarationForValue(
         _forest.createPropertyGet(fileOffset,
-            _helper.createVariableGet(variable, receiver.fileOffset), name));
+            _helper.createVariableGet(variable, receiver.fileOffset), name,
+            isNullAware: false));
     Expression binary = _helper.forest.createBinary(offset,
         _helper.createVariableGet(read, fileOffset), binaryOperator, value);
     VariableDeclarationImpl write = _helper.createVariableDeclarationForValue(
@@ -562,7 +564,8 @@ class PropertyAccessGenerator extends Generator {
             _helper.createVariableGet(variable, receiver.fileOffset),
             name,
             binary,
-            forEffect: true));
+            forEffect: true,
+            isNullAware: false));
     return new PropertyPostIncDec(variable, read, write)..fileOffset = offset;
   }
 
@@ -654,7 +657,8 @@ class ThisPropertyAccessGenerator extends Generator {
   }
 
   Expression _createRead() {
-    return _forest.createPropertyGet(fileOffset, _thisExpression, name);
+    return _forest.createPropertyGet(fileOffset, _thisExpression, name,
+        isNullAware: false);
   }
 
   @override
@@ -666,7 +670,7 @@ class ThisPropertyAccessGenerator extends Generator {
       {required bool forEffect}) {
     return _helper.forest.createPropertySet(
         fileOffset, _thisExpression, name, value,
-        forEffect: forEffect);
+        forEffect: forEffect, isNullAware: false);
   }
 
   @override
@@ -730,17 +734,13 @@ class ThisPropertyAccessGenerator extends Generator {
 }
 
 class NullAwarePropertyAccessGenerator extends Generator {
-  final VariableDeclaration receiver;
-
-  final Expression receiverExpression;
+  final Expression receiver;
 
   final Name name;
 
-  NullAwarePropertyAccessGenerator(ExpressionGeneratorHelper helper,
-      Token token, this.receiverExpression, this.name)
-      : this.receiver =
-            helper.createVariableDeclarationForValue(receiverExpression),
-        super(helper, token);
+  NullAwarePropertyAccessGenerator(
+      ExpressionGeneratorHelper helper, Token token, this.receiver, this.name)
+      : super(helper, token);
 
   @override
   // Coverage-ignore(suite): Not run.
@@ -752,37 +752,20 @@ class NullAwarePropertyAccessGenerator extends Generator {
 
   @override
   Expression buildSimpleRead() {
-    VariableDeclarationImpl variable =
-        _helper.createVariableDeclarationForValue(receiverExpression);
-    Expression read = _forest.createPropertyGet(
-        fileOffset,
-        _helper.createVariableGet(variable, receiverExpression.fileOffset,
-            forNullGuardedAccess: true),
-        name);
-    return new NullAwarePropertyGet(variable, read)
-      ..fileOffset = receiverExpression.fileOffset;
+    return _forest.createPropertyGet(fileOffset, receiver, name,
+        isNullAware: true);
   }
 
   @override
   Expression buildAssignment(Expression value, {bool voidContext = false}) {
-    VariableDeclarationImpl variable =
-        _helper.createVariableDeclarationForValue(receiverExpression);
-    Expression read = _helper.forest.createPropertySet(
-        fileOffset,
-        _helper.createVariableGet(variable, receiverExpression.fileOffset,
-            forNullGuardedAccess: true),
-        name,
-        value,
-        forEffect: voidContext,
-        readOnlyReceiver: true);
-    return new NullAwarePropertySet(variable, read)
-      ..fileOffset = receiverExpression.fileOffset;
+    return _forest.createPropertySet(fileOffset, receiver, name, value,
+        forEffect: voidContext, isNullAware: true);
   }
 
   @override
   Expression buildIfNullAssignment(Expression value, DartType type, int offset,
       {bool voidContext = false}) {
-    return new NullAwareIfNullSet(receiverExpression, name, value,
+    return new NullAwareIfNullSet(receiver, name, value,
         forEffect: voidContext,
         readOffset: fileOffset,
         testOffset: offset,
@@ -796,8 +779,7 @@ class NullAwarePropertyAccessGenerator extends Generator {
       bool voidContext = false,
       bool isPreIncDec = false,
       bool isPostIncDec = false}) {
-    return new NullAwareCompoundSet(
-        receiverExpression, name, binaryOperator, value,
+    return new NullAwareCompoundSet(receiver, name, binaryOperator, value,
         readOffset: fileOffset,
         binaryOffset: offset,
         writeOffset: fileOffset,
@@ -834,8 +816,6 @@ class NullAwarePropertyAccessGenerator extends Generator {
     NameSystem syntheticNames = new NameSystem();
     sink.write(", receiver: ");
     printNodeOn(receiver, sink, syntheticNames: syntheticNames);
-    sink.write(", receiverExpression: ");
-    printNodeOn(receiverExpression, sink, syntheticNames: syntheticNames);
     sink.write(", name: ");
     sink.write(name.text);
   }
@@ -989,43 +969,14 @@ class IndexedAccessGenerator extends Generator {
 
   @override
   Expression buildSimpleRead() {
-    VariableDeclarationImpl? variable;
-    Expression receiverValue;
-    if (isNullAware) {
-      variable = _helper.createVariableDeclarationForValue(receiver);
-      receiverValue = _helper.createVariableGet(variable, fileOffset,
-          forNullGuardedAccess: true);
-    } else {
-      receiverValue = receiver;
-    }
-    Expression result =
-        _forest.createIndexGet(fileOffset, receiverValue, index);
-    if (isNullAware) {
-      result = new NullAwareMethodInvocation(variable!, result)
-        ..fileOffset = fileOffset;
-    }
-    return result;
+    return _forest.createIndexGet(fileOffset, receiver, index,
+        isNullAware: isNullAware);
   }
 
   @override
   Expression buildAssignment(Expression value, {bool voidContext = false}) {
-    VariableDeclarationImpl? variable;
-    Expression receiverValue;
-    if (isNullAware) {
-      variable = _helper.createVariableDeclarationForValue(receiver);
-      receiverValue = _helper.createVariableGet(variable, fileOffset,
-          forNullGuardedAccess: true);
-    } else {
-      receiverValue = receiver;
-    }
-    Expression result = _forest.createIndexSet(
-        fileOffset, receiverValue, index, value,
-        forEffect: voidContext);
-    if (isNullAware) {
-      result = new NullAwareMethodInvocation(variable!, result)
-        ..fileOffset = fileOffset;
-    }
-    return result;
+    return _forest.createIndexSet(fileOffset, receiver, index, value,
+        forEffect: voidContext, isNullAware: isNullAware);
   }
 
   @override
@@ -1157,14 +1108,15 @@ class ThisIndexedAccessGenerator extends Generator {
   @override
   Expression buildSimpleRead() {
     Expression receiver = _helper.forest.createThisExpression(fileOffset);
-    return _forest.createIndexGet(fileOffset, receiver, index);
+    return _forest.createIndexGet(fileOffset, receiver, index,
+        isNullAware: isNullAware);
   }
 
   @override
   Expression buildAssignment(Expression value, {bool voidContext = false}) {
     Expression receiver = _helper.forest.createThisExpression(fileOffset);
     return _forest.createIndexSet(fileOffset, receiver, index, value,
-        forEffect: voidContext);
+        forEffect: voidContext, isNullAware: isNullAware);
   }
 
   @override

pkg/front_end/lib/src/kernel/forest.dart

@@ -681,8 +681,10 @@ class Forest {
   }
 
   Expression createMethodInvocation(
-      int fileOffset, Expression expression, Name name, Arguments arguments) {
-    return new MethodInvocation(expression, name, arguments)
+      int fileOffset, Expression expression, Name name, Arguments arguments,
+      {required bool isNullAware}) {
+    return new MethodInvocation(expression, name, arguments,
+        isNullAware: isNullAware)
       ..fileOffset = fileOffset;
   }
 
@@ -696,27 +698,35 @@ class Forest {
     return new NullCheck(expression)..fileOffset = fileOffset;
   }
 
-  Expression createPropertyGet(int fileOffset, Expression receiver, Name name) {
-    return new PropertyGet(receiver, name)..fileOffset = fileOffset;
+  Expression createPropertyGet(int fileOffset, Expression receiver, Name name,
+      {required bool isNullAware}) {
+    return new PropertyGet(receiver, name, isNullAware: isNullAware)
+      ..fileOffset = fileOffset;
   }
 
   Expression createPropertySet(
       int fileOffset, Expression receiver, Name name, Expression value,
-      {required bool forEffect, bool readOnlyReceiver = false}) {
+      {required bool forEffect,
+      bool readOnlyReceiver = false,
+      required bool isNullAware}) {
     return new PropertySet(receiver, name, value,
-        forEffect: forEffect, readOnlyReceiver: readOnlyReceiver)
+        forEffect: forEffect,
+        readOnlyReceiver: readOnlyReceiver,
+        isNullAware: isNullAware)
       ..fileOffset = fileOffset;
   }
 
-  IndexGet createIndexGet(
-      int fileOffset, Expression receiver, Expression index) {
-    return new IndexGet(receiver, index)..fileOffset = fileOffset;
+  IndexGet createIndexGet(int fileOffset, Expression receiver, Expression index,
+      {required bool isNullAware}) {
+    return new IndexGet(receiver, index, isNullAware: isNullAware)
+      ..fileOffset = fileOffset;
   }
 
   IndexSet createIndexSet(
       int fileOffset, Expression receiver, Expression index, Expression value,
-      {required bool forEffect}) {
-    return new IndexSet(receiver, index, value, forEffect: forEffect)
+      {required bool forEffect, required bool isNullAware}) {
+    return new IndexSet(receiver, index, value,
+        forEffect: forEffect, isNullAware: isNullAware)
       ..fileOffset = fileOffset;
   }