From 2132a0c7a3d2a107190238ca0c5570baa0467bb7 Mon Sep 17 00:00:00 2001
From: Ferhat <ferhat@gmail.com>
Date: Wed, 26 Feb 2020 15:51:30 -0800
Subject: [PATCH] Revert "[Perf/codesize] Reduce constraint member reads during
 layout (#51418)" (#51489)

This reverts commit 69080e07e6bb178332bf546cf83054a85b91b2fe.
---
 packages/flutter/lib/src/cupertino/action_sheet.dart          | 1 -
 packages/flutter/lib/src/cupertino/dialog.dart                | 1 -
 packages/flutter/lib/src/cupertino/refresh.dart               | 1 -
 packages/flutter/lib/src/cupertino/segmented_control.dart     | 1 -
 .../flutter/lib/src/cupertino/sliding_segmented_control.dart  | 1 -
 packages/flutter/lib/src/cupertino/text_selection.dart        | 1 -
 packages/flutter/lib/src/material/app_bar.dart                | 1 -
 packages/flutter/lib/src/material/button.dart                 | 1 -
 packages/flutter/lib/src/material/floating_action_button.dart | 1 -
 packages/flutter/lib/src/material/input_decorator.dart        | 1 -
 packages/flutter/lib/src/material/list_tile.dart              | 1 -
 packages/flutter/lib/src/rendering/animated_size.dart         | 2 +-
 packages/flutter/lib/src/rendering/editable.dart              | 1 -
 packages/flutter/lib/src/rendering/flex.dart                  | 2 --
 packages/flutter/lib/src/rendering/flow.dart                  | 1 -
 packages/flutter/lib/src/rendering/list_body.dart             | 1 -
 packages/flutter/lib/src/rendering/paragraph.dart             | 1 -
 packages/flutter/lib/src/rendering/proxy_box.dart             | 2 --
 packages/flutter/lib/src/rendering/shifted_box.dart           | 4 ----
 packages/flutter/lib/src/rendering/sliver.dart                | 1 -
 packages/flutter/lib/src/rendering/sliver_fill.dart           | 3 ---
 .../flutter/lib/src/rendering/sliver_fixed_extent_list.dart   | 1 -
 packages/flutter/lib/src/rendering/sliver_grid.dart           | 1 -
 packages/flutter/lib/src/rendering/sliver_list.dart           | 1 -
 packages/flutter/lib/src/rendering/sliver_padding.dart        | 1 -
 .../flutter/lib/src/rendering/sliver_persistent_header.dart   | 3 ---
 packages/flutter/lib/src/rendering/stack.dart                 | 1 -
 packages/flutter/lib/src/rendering/table.dart                 | 1 -
 packages/flutter/lib/src/rendering/viewport.dart              | 1 -
 packages/flutter/lib/src/rendering/wrap.dart                  | 1 -
 packages/flutter/lib/src/widgets/layout_builder.dart          | 1 -
 .../flutter/lib/src/widgets/single_child_scroll_view.dart     | 1 -
 32 files changed, 1 insertion(+), 41 deletions(-)

diff --git a/packages/flutter/lib/src/cupertino/action_sheet.dart b/packages/flutter/lib/src/cupertino/action_sheet.dart
index ce19f755d3..49f4c533d6 100644
--- a/packages/flutter/lib/src/cupertino/action_sheet.dart
+++ b/packages/flutter/lib/src/cupertino/action_sheet.dart
@@ -668,7 +668,6 @@ class _RenderCupertinoAlert extends RenderBox {
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     final bool hasDivider = contentSection.getMaxIntrinsicHeight(constraints.maxWidth) > 0.0
         && actionsSection.getMaxIntrinsicHeight(constraints.maxWidth) > 0.0;
     final double dividerThickness = hasDivider ? _dividerThickness : 0.0;
diff --git a/packages/flutter/lib/src/cupertino/dialog.dart b/packages/flutter/lib/src/cupertino/dialog.dart
index 79c6b7fd46..305bba5d55 100644
--- a/packages/flutter/lib/src/cupertino/dialog.dart
+++ b/packages/flutter/lib/src/cupertino/dialog.dart
@@ -1540,7 +1540,6 @@ class _RenderCupertinoDialogActions extends RenderBox
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     if (_isSingleButtonRow(dialogWidth)) {
       if (childCount == 1) {
         // We have 1 button. Our size is the width of the dialog and the height
diff --git a/packages/flutter/lib/src/cupertino/refresh.dart b/packages/flutter/lib/src/cupertino/refresh.dart
index 342d25ed37..1436da182c 100644
--- a/packages/flutter/lib/src/cupertino/refresh.dart
+++ b/packages/flutter/lib/src/cupertino/refresh.dart
@@ -104,7 +104,6 @@ class _RenderCupertinoSliverRefresh extends RenderSliver
 
   @override
   void performLayout() {
-    final SliverConstraints constraints = this.constraints;
     // Only pulling to refresh from the top is currently supported.
     assert(constraints.axisDirection == AxisDirection.down);
     assert(constraints.growthDirection == GrowthDirection.forward);
diff --git a/packages/flutter/lib/src/cupertino/segmented_control.dart b/packages/flutter/lib/src/cupertino/segmented_control.dart
index 3506c0ad50..4d5cb5fc18 100644
--- a/packages/flutter/lib/src/cupertino/segmented_control.dart
+++ b/packages/flutter/lib/src/cupertino/segmented_control.dart
@@ -628,7 +628,6 @@ class _RenderSegmentedControl<T> extends RenderBox
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     double maxHeight = _kMinSegmentedControlHeight;
 
     double childWidth = constraints.minWidth / childCount;
diff --git a/packages/flutter/lib/src/cupertino/sliding_segmented_control.dart b/packages/flutter/lib/src/cupertino/sliding_segmented_control.dart
index e34c4946f3..b593fd8061 100644
--- a/packages/flutter/lib/src/cupertino/sliding_segmented_control.dart
+++ b/packages/flutter/lib/src/cupertino/sliding_segmented_control.dart
@@ -828,7 +828,6 @@ class _RenderSegmentedControl<T> extends RenderBox
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     double childWidth = (constraints.minWidth - totalSeparatorWidth) / childCount;
     double maxHeight = _kMinSegmentedControlHeight;
 
diff --git a/packages/flutter/lib/src/cupertino/text_selection.dart b/packages/flutter/lib/src/cupertino/text_selection.dart
index bbb0524070..58835fc272 100644
--- a/packages/flutter/lib/src/cupertino/text_selection.dart
+++ b/packages/flutter/lib/src/cupertino/text_selection.dart
@@ -159,7 +159,6 @@ class _ToolbarRenderBox extends RenderShiftedBox {
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     size = constraints.biggest;
 
     if (child == null) {
diff --git a/packages/flutter/lib/src/material/app_bar.dart b/packages/flutter/lib/src/material/app_bar.dart
index b06708138f..e2ff809c92 100644
--- a/packages/flutter/lib/src/material/app_bar.dart
+++ b/packages/flutter/lib/src/material/app_bar.dart
@@ -1346,7 +1346,6 @@ class _RenderAppBarTitleBox extends RenderAligningShiftedBox {
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     final BoxConstraints innerConstraints = constraints.copyWith(maxHeight: double.infinity);
     child.layout(innerConstraints, parentUsesSize: true);
     size = constraints.constrain(child.size);
diff --git a/packages/flutter/lib/src/material/button.dart b/packages/flutter/lib/src/material/button.dart
index 15aef5239f..43e8730ca1 100644
--- a/packages/flutter/lib/src/material/button.dart
+++ b/packages/flutter/lib/src/material/button.dart
@@ -509,7 +509,6 @@ class _RenderInputPadding extends RenderShiftedBox {
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     if (child != null) {
       child.layout(constraints, parentUsesSize: true);
       final double height = math.max(child.size.width, minSize.width);
diff --git a/packages/flutter/lib/src/material/floating_action_button.dart b/packages/flutter/lib/src/material/floating_action_button.dart
index a7a4ad3ae8..32b6e3c584 100644
--- a/packages/flutter/lib/src/material/floating_action_button.dart
+++ b/packages/flutter/lib/src/material/floating_action_button.dart
@@ -582,7 +582,6 @@ class _RenderChildOverflowBox extends RenderAligningShiftedBox {
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     if (child != null) {
       child.layout(const BoxConstraints(), parentUsesSize: true);
       size = Size(
diff --git a/packages/flutter/lib/src/material/input_decorator.dart b/packages/flutter/lib/src/material/input_decorator.dart
index 454183b733..3fcd159546 100644
--- a/packages/flutter/lib/src/material/input_decorator.dart
+++ b/packages/flutter/lib/src/material/input_decorator.dart
@@ -1257,7 +1257,6 @@ class _RenderDecoration extends RenderBox {
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     _labelTransform = null;
     final _RenderDecorationLayout layout = _layout(constraints);
 
diff --git a/packages/flutter/lib/src/material/list_tile.dart b/packages/flutter/lib/src/material/list_tile.dart
index 26ee74a4c7..8fa5363e2e 100644
--- a/packages/flutter/lib/src/material/list_tile.dart
+++ b/packages/flutter/lib/src/material/list_tile.dart
@@ -1328,7 +1328,6 @@ class _RenderListTile extends RenderBox {
   // https://material.io/design/components/lists.html#specs
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     final bool hasLeading = leading != null;
     final bool hasSubtitle = subtitle != null;
     final bool hasTrailing = trailing != null;
diff --git a/packages/flutter/lib/src/rendering/animated_size.dart b/packages/flutter/lib/src/rendering/animated_size.dart
index 4b02cbf619..1e4dfe3b3a 100644
--- a/packages/flutter/lib/src/rendering/animated_size.dart
+++ b/packages/flutter/lib/src/rendering/animated_size.dart
@@ -170,7 +170,7 @@ class RenderAnimatedSize extends RenderAligningShiftedBox {
   void performLayout() {
     _lastValue = _controller.value;
     _hasVisualOverflow = false;
-    final BoxConstraints constraints = this.constraints;
+
     if (child == null || constraints.isTight) {
       _controller.stop();
       size = _sizeTween.begin = _sizeTween.end = constraints.smallest;
diff --git a/packages/flutter/lib/src/rendering/editable.dart b/packages/flutter/lib/src/rendering/editable.dart
index 7f9176b95f..5fa7765fe5 100644
--- a/packages/flutter/lib/src/rendering/editable.dart
+++ b/packages/flutter/lib/src/rendering/editable.dart
@@ -1743,7 +1743,6 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
   }
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     _layoutText(minWidth: constraints.minWidth, maxWidth: constraints.maxWidth);
     _caretPrototype = _getCaretPrototype;
     _selectionRects = null;
diff --git a/packages/flutter/lib/src/rendering/flex.dart b/packages/flutter/lib/src/rendering/flex.dart
index 45cdc722a7..75ae5d62a3 100644
--- a/packages/flutter/lib/src/rendering/flex.dart
+++ b/packages/flutter/lib/src/rendering/flex.dart
@@ -636,8 +636,6 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
   @override
   void performLayout() {
     assert(_debugHasNecessaryDirections);
-    final BoxConstraints constraints = this.constraints;
-
     // Determine used flex factor, size inflexible items, calculate free space.
     int totalFlex = 0;
     int totalChildren = 0;
diff --git a/packages/flutter/lib/src/rendering/flow.dart b/packages/flutter/lib/src/rendering/flow.dart
index 1ec9ef68e9..7a53be1ee9 100644
--- a/packages/flutter/lib/src/rendering/flow.dart
+++ b/packages/flutter/lib/src/rendering/flow.dart
@@ -279,7 +279,6 @@ class RenderFlow extends RenderBox
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     size = _getSize(constraints);
     int i = 0;
     _randomAccessChildren.clear();
diff --git a/packages/flutter/lib/src/rendering/list_body.dart b/packages/flutter/lib/src/rendering/list_body.dart
index 00e5251c31..cb05672cf0 100644
--- a/packages/flutter/lib/src/rendering/list_body.dart
+++ b/packages/flutter/lib/src/rendering/list_body.dart
@@ -63,7 +63,6 @@ class RenderListBody extends RenderBox
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     assert(() {
       switch (mainAxis) {
         case Axis.horizontal:
diff --git a/packages/flutter/lib/src/rendering/paragraph.dart b/packages/flutter/lib/src/rendering/paragraph.dart
index c71f8a6f84..556f89face 100644
--- a/packages/flutter/lib/src/rendering/paragraph.dart
+++ b/packages/flutter/lib/src/rendering/paragraph.dart
@@ -575,7 +575,6 @@ class RenderParagraph extends RenderBox
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     _layoutChildren(constraints);
     _layoutTextWithConstraints(constraints);
     _setParentData();
diff --git a/packages/flutter/lib/src/rendering/proxy_box.dart b/packages/flutter/lib/src/rendering/proxy_box.dart
index 33db06ce5a..da754538b3 100644
--- a/packages/flutter/lib/src/rendering/proxy_box.dart
+++ b/packages/flutter/lib/src/rendering/proxy_box.dart
@@ -260,7 +260,6 @@ class RenderConstrainedBox extends RenderProxyBox {
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     if (child != null) {
       child.layout(_additionalConstraints.enforce(constraints), parentUsesSize: true);
       size = child.size;
@@ -352,7 +351,6 @@ class RenderLimitedBox extends RenderProxyBox {
   @override
   void performLayout() {
     if (child != null) {
-      final BoxConstraints constraints = this.constraints;
       child.layout(_limitConstraints(constraints), parentUsesSize: true);
       size = constraints.constrain(child.size);
     } else {
diff --git a/packages/flutter/lib/src/rendering/shifted_box.dart b/packages/flutter/lib/src/rendering/shifted_box.dart
index 832359cdad..e73a832673 100644
--- a/packages/flutter/lib/src/rendering/shifted_box.dart
+++ b/packages/flutter/lib/src/rendering/shifted_box.dart
@@ -193,7 +193,6 @@ class RenderPadding extends RenderShiftedBox {
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     _resolve();
     assert(_resolvedPadding != null);
     if (child == null) {
@@ -386,7 +385,6 @@ class RenderPositionedBox extends RenderAligningShiftedBox {
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     final bool shrinkWrapWidth = _widthFactor != null || constraints.maxWidth == double.infinity;
     final bool shrinkWrapHeight = _heightFactor != null || constraints.maxHeight == double.infinity;
 
@@ -651,7 +649,6 @@ class RenderUnconstrainedBox extends RenderAligningShiftedBox with DebugOverflow
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     if (child != null) {
       // Let the child lay itself out at it's "natural" size, but if
       // constrainedAxis is non-null, keep any constraints on that axis.
@@ -1186,7 +1183,6 @@ class RenderBaseline extends RenderShiftedBox {
   @override
   void performLayout() {
     if (child != null) {
-      final BoxConstraints constraints = this.constraints;
       child.layout(constraints.loosen(), parentUsesSize: true);
       final double childBaseline = child.getDistanceToBaseline(baselineType);
       final double actualBaseline = baseline;
diff --git a/packages/flutter/lib/src/rendering/sliver.dart b/packages/flutter/lib/src/rendering/sliver.dart
index c7b92014db..8800c37c65 100644
--- a/packages/flutter/lib/src/rendering/sliver.dart
+++ b/packages/flutter/lib/src/rendering/sliver.dart
@@ -1813,7 +1813,6 @@ class RenderSliverToBoxAdapter extends RenderSliverSingleBoxAdapter {
       geometry = SliverGeometry.zero;
       return;
     }
-    final SliverConstraints constraints = this.constraints;
     child.layout(constraints.asBoxConstraints(), parentUsesSize: true);
     double childExtent;
     switch (constraints.axis) {
diff --git a/packages/flutter/lib/src/rendering/sliver_fill.dart b/packages/flutter/lib/src/rendering/sliver_fill.dart
index fc51eb6a8b..066bd99d5e 100644
--- a/packages/flutter/lib/src/rendering/sliver_fill.dart
+++ b/packages/flutter/lib/src/rendering/sliver_fill.dart
@@ -87,7 +87,6 @@ class RenderSliverFillRemainingWithScrollable extends RenderSliverSingleBoxAdapt
 
   @override
   void performLayout() {
-    final SliverConstraints constraints = this.constraints;
     // TODO(Piinks): This may fill too much space for NestedScrollView, https://github.com/flutter/flutter/issues/46028
     final double extent = constraints.remainingPaintExtent - math.min(constraints.overlap, 0.0);
 
@@ -138,7 +137,6 @@ class RenderSliverFillRemaining extends RenderSliverSingleBoxAdapter {
 
   @override
   void performLayout() {
-    final SliverConstraints constraints = this.constraints;
     // The remaining space in the viewportMainAxisExtent. Can be <= 0 if we have
     // scrolled beyond the extent of the screen.
     double extent = constraints.viewportMainAxisExtent - constraints.precedingScrollExtent;
@@ -211,7 +209,6 @@ class RenderSliverFillRemainingAndOverscroll extends RenderSliverSingleBoxAdapte
 
   @override
   void performLayout() {
-    final SliverConstraints constraints = this.constraints;
     // The remaining space in the viewportMainAxisExtent. Can be <= 0 if we have
     // scrolled beyond the extent of the screen.
     double extent = constraints.viewportMainAxisExtent - constraints.precedingScrollExtent;
diff --git a/packages/flutter/lib/src/rendering/sliver_fixed_extent_list.dart b/packages/flutter/lib/src/rendering/sliver_fixed_extent_list.dart
index 14cebe9afc..ae40e4764b 100644
--- a/packages/flutter/lib/src/rendering/sliver_fixed_extent_list.dart
+++ b/packages/flutter/lib/src/rendering/sliver_fixed_extent_list.dart
@@ -164,7 +164,6 @@ abstract class RenderSliverFixedExtentBoxAdaptor extends RenderSliverMultiBoxAda
 
   @override
   void performLayout() {
-    final SliverConstraints constraints = this.constraints;
     childManager.didStartLayout();
     childManager.setDidUnderflow(false);
 
diff --git a/packages/flutter/lib/src/rendering/sliver_grid.dart b/packages/flutter/lib/src/rendering/sliver_grid.dart
index 34be07f118..be2351109b 100644
--- a/packages/flutter/lib/src/rendering/sliver_grid.dart
+++ b/packages/flutter/lib/src/rendering/sliver_grid.dart
@@ -511,7 +511,6 @@ class RenderSliverGrid extends RenderSliverMultiBoxAdaptor {
 
   @override
   void performLayout() {
-    final SliverConstraints constraints = this.constraints;
     childManager.didStartLayout();
     childManager.setDidUnderflow(false);
 
diff --git a/packages/flutter/lib/src/rendering/sliver_list.dart b/packages/flutter/lib/src/rendering/sliver_list.dart
index 4635d84202..a8e8801a5b 100644
--- a/packages/flutter/lib/src/rendering/sliver_list.dart
+++ b/packages/flutter/lib/src/rendering/sliver_list.dart
@@ -44,7 +44,6 @@ class RenderSliverList extends RenderSliverMultiBoxAdaptor {
 
   @override
   void performLayout() {
-    final SliverConstraints constraints = this.constraints;
     childManager.didStartLayout();
     childManager.setDidUnderflow(false);
 
diff --git a/packages/flutter/lib/src/rendering/sliver_padding.dart b/packages/flutter/lib/src/rendering/sliver_padding.dart
index c923fa9562..9891ce53ae 100644
--- a/packages/flutter/lib/src/rendering/sliver_padding.dart
+++ b/packages/flutter/lib/src/rendering/sliver_padding.dart
@@ -118,7 +118,6 @@ abstract class RenderSliverEdgeInsetsPadding extends RenderSliver with RenderObj
 
   @override
   void performLayout() {
-    final SliverConstraints constraints = this.constraints;
     assert(resolvedPadding != null);
     final double beforePadding = this.beforePadding;
     final double afterPadding = this.afterPadding;
diff --git a/packages/flutter/lib/src/rendering/sliver_persistent_header.dart b/packages/flutter/lib/src/rendering/sliver_persistent_header.dart
index 2bf1fd3df9..1e236892d8 100644
--- a/packages/flutter/lib/src/rendering/sliver_persistent_header.dart
+++ b/packages/flutter/lib/src/rendering/sliver_persistent_header.dart
@@ -331,7 +331,6 @@ abstract class RenderSliverScrollingPersistentHeader extends RenderSliverPersist
 
   @override
   void performLayout() {
-    final SliverConstraints constraints = this.constraints;
     final double maxExtent = this.maxExtent;
     layoutChild(constraints.scrollOffset, maxExtent);
     final double paintExtent = maxExtent - constraints.scrollOffset;
@@ -370,7 +369,6 @@ abstract class RenderSliverPinnedPersistentHeader extends RenderSliverPersistent
 
   @override
   void performLayout() {
-    final SliverConstraints constraints = this.constraints;
     final double maxExtent = this.maxExtent;
     final bool overlapsContent = constraints.overlap > 0.0;
     excludeFromSemanticsScrolling = overlapsContent || (constraints.scrollOffset > maxExtent - minExtent);
@@ -554,7 +552,6 @@ abstract class RenderSliverFloatingPersistentHeader extends RenderSliverPersiste
 
   @override
   void performLayout() {
-    final SliverConstraints constraints = this.constraints;
     final double maxExtent = this.maxExtent;
     if (_lastActualScrollOffset != null && // We've laid out at least once to get an initial position, and either
         ((constraints.scrollOffset < _lastActualScrollOffset) || // we are scrolling back, so should reveal, or
diff --git a/packages/flutter/lib/src/rendering/stack.dart b/packages/flutter/lib/src/rendering/stack.dart
index 5eacb7bfdc..c72c1d146e 100644
--- a/packages/flutter/lib/src/rendering/stack.dart
+++ b/packages/flutter/lib/src/rendering/stack.dart
@@ -517,7 +517,6 @@ class RenderStack extends RenderBox
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     _resolve();
     assert(_resolvedAlignment != null);
     _hasVisualOverflow = false;
diff --git a/packages/flutter/lib/src/rendering/table.dart b/packages/flutter/lib/src/rendering/table.dart
index df14823a80..f627f952e0 100644
--- a/packages/flutter/lib/src/rendering/table.dart
+++ b/packages/flutter/lib/src/rendering/table.dart
@@ -992,7 +992,6 @@ class RenderTable extends RenderBox {
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     final int rows = this.rows;
     final int columns = this.columns;
     assert(_children.length == rows * columns);
diff --git a/packages/flutter/lib/src/rendering/viewport.dart b/packages/flutter/lib/src/rendering/viewport.dart
index 6b2a5dbf39..8dde2655f8 100644
--- a/packages/flutter/lib/src/rendering/viewport.dart
+++ b/packages/flutter/lib/src/rendering/viewport.dart
@@ -1699,7 +1699,6 @@ class RenderShrinkWrappingViewport extends RenderViewportBase<SliverLogicalConta
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     if (firstChild == null) {
       switch (axis) {
         case Axis.vertical:
diff --git a/packages/flutter/lib/src/rendering/wrap.dart b/packages/flutter/lib/src/rendering/wrap.dart
index 30cdc10b84..b0306259b1 100644
--- a/packages/flutter/lib/src/rendering/wrap.dart
+++ b/packages/flutter/lib/src/rendering/wrap.dart
@@ -565,7 +565,6 @@ class RenderWrap extends RenderBox with ContainerRenderObjectMixin<RenderBox, Wr
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     assert(_debugHasNecessaryDirections);
     _hasVisualOverflow = false;
     RenderBox child = firstChild;
diff --git a/packages/flutter/lib/src/widgets/layout_builder.dart b/packages/flutter/lib/src/widgets/layout_builder.dart
index 4f14fb4e4a..77e6399eec 100644
--- a/packages/flutter/lib/src/widgets/layout_builder.dart
+++ b/packages/flutter/lib/src/widgets/layout_builder.dart
@@ -238,7 +238,6 @@ class _RenderLayoutBuilder extends RenderBox with RenderObjectWithChildMixin<Ren
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     layoutAndBuildChild();
     if (child != null) {
       child.layout(constraints, parentUsesSize: true);
diff --git a/packages/flutter/lib/src/widgets/single_child_scroll_view.dart b/packages/flutter/lib/src/widgets/single_child_scroll_view.dart
index f4deca6150..6b5dc18c7a 100644
--- a/packages/flutter/lib/src/widgets/single_child_scroll_view.dart
+++ b/packages/flutter/lib/src/widgets/single_child_scroll_view.dart
@@ -505,7 +505,6 @@ class _RenderSingleChildViewport extends RenderBox with RenderObjectWithChildMix
 
   @override
   void performLayout() {
-    final BoxConstraints constraints = this.constraints;
     if (child == null) {
       size = constraints.smallest;
     } else {