enable always_require_non_null_named_parameters lint (#9948)

* enable always_require_non_null_named_parameters lint

* Update home.dart

.analysis_options

@@ -67,7 +67,7 @@ linter:
     # === style rules ===
     - always_declare_return_types
     # - always_put_control_body_on_new_line # not yet tested
-    # - always_require_non_null_named_parameters # not yet tested
+    - always_require_non_null_named_parameters
     - always_specify_types
     - annotate_overrides
     # - avoid_annotating_with_dynamic # not yet tested

.analysis_options_repo

@@ -65,7 +65,7 @@ linter:
     # === style rules ===
     - always_declare_return_types
     # - always_put_control_body_on_new_line # not yet tested
-    # - always_require_non_null_named_parameters # not yet tested
+    - always_require_non_null_named_parameters
     - always_specify_types
     - annotate_overrides
     # - avoid_annotating_with_dynamic # not yet tested

examples/catalog/lib/animated_list.dart

@@ -20,9 +20,9 @@ import 'package:flutter/material.dart';
 class CardItem extends StatelessWidget {
   CardItem({
     Key key,
-    this.animation,
+    @required this.animation,
     this.onTap,
-    this.item,
+    @required this.item,
     this.selected: false
   }) : super(key: key) {
     assert(animation != null);

examples/flutter_gallery/lib/demo/animation/home.dart

@@ -371,9 +371,11 @@ class _AllSectionsView extends AnimatedWidget {
 // app bar's height is _kAppBarMidHeight and only one section heading is
 // visible.
 class _SnappingScrollPhysics extends ClampingScrollPhysics {
-  _SnappingScrollPhysics({ ScrollPhysics parent, this.midScrollOffset }) : super(parent: parent) {
-    assert(midScrollOffset != null);
-  }
+  _SnappingScrollPhysics({
+    ScrollPhysics parent,
+    @required this.midScrollOffset,
+  }) : assert(midScrollOffset != null),
+       super(parent: parent);
 
   final double midScrollOffset;
 

packages/flutter/lib/src/gestures/velocity_tracker.dart

@@ -4,6 +4,8 @@
 
 import 'dart:ui' show Offset;
 
+import 'package:flutter/foundation.dart';
+
 import 'lsq_solver.dart';
 
 export 'dart:ui' show Offset;
@@ -13,7 +15,9 @@ class Velocity {
   /// Creates a velocity.
   ///
   /// The [pixelsPerSecond] argument must not be null.
-  const Velocity({ this.pixelsPerSecond }) : assert(pixelsPerSecond != null);
+  const Velocity({
+    @required this.pixelsPerSecond,
+  }) : assert(pixelsPerSecond != null);
 
   /// A velocity that isn't moving at all.
   static const Velocity zero = const Velocity(pixelsPerSecond: Offset.zero);
@@ -90,10 +94,10 @@ class VelocityEstimate {
   ///
   /// [pixelsPerSecond], [confidence], [duration], and [offset] must not be null.
   const VelocityEstimate({
-    this.pixelsPerSecond,
-    this.confidence,
-    this.duration,
-    this.offset,
+    @required this.pixelsPerSecond,
+    @required this.confidence,
+    @required this.duration,
+    @required this.offset,
   }) : assert(pixelsPerSecond != null),
        assert(confidence != null),
        assert(duration != null),

packages/flutter/lib/src/material/data_table.dart

@@ -91,7 +91,7 @@ class DataRow {
     this.key,
     this.selected: false,
     this.onSelectChanged,
-    this.cells
+    @required this.cells
   }) : assert(cells != null);
 
   /// Creates the configuration for a row of a [DataTable], deriving
@@ -102,7 +102,7 @@ class DataRow {
     int index,
     this.selected: false,
     this.onSelectChanged,
-    this.cells
+    @required this.cells
   }) : assert(cells != null),
        key = new ValueKey<int>(index);
 

packages/flutter/lib/src/painting/box_painter.dart

@@ -786,7 +786,7 @@ class LinearGradient extends Gradient {
   const LinearGradient({
     this.begin: FractionalOffset.centerLeft,
     this.end: FractionalOffset.centerRight,
-    this.colors,
+    @required this.colors,
     this.stops,
     this.tileMode: TileMode.clamp,
   }) : assert(begin != null),
@@ -1000,7 +1000,7 @@ class RadialGradient extends Gradient {
   const RadialGradient({
     this.center: FractionalOffset.center,
     this.radius: 0.5,
-    this.colors,
+    @required this.colors,
     this.stops,
     this.tileMode: TileMode.clamp,
   }) : assert(center != null),
@@ -1262,7 +1262,7 @@ class DecorationImage {
   ///
   /// The [image] argument must not be null.
   const DecorationImage({
-    this.image,
+    @required this.image,
     this.fit,
     this.repeat: ImageRepeat.noRepeat,
     this.centerSlice,