Positioned: Another exception was thrown

[renzorodrigues]

Can someone explain to me why is this problem ocurring with Positioned widget?

Stack(children: <Widget>[ Positioned( top: 40, child: Container( color: Colors.indigo, child: Column( children: <Widget>[ loginButtonEmail(), loginButtonFacebook(), loginButtonGoogle(), ], )), ), ]),

Error:
`

Performing hot reload... ⣷I/flutter ( 4706): ══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════
I/flutter ( 4706): The following assertion was thrown during performLayout():
I/flutter ( 4706): 'package:flutter/src/rendering/object.dart': Failed assertion: line 1588 pos 12:
I/flutter ( 4706): '!_debugDoingThisLayout': is not true.
I/flutter ( 4706):
I/flutter ( 4706): Either the assertion indicates an error in the framework itself, or we should provide substantially
I/flutter ( 4706): more information in this error message to help you determine and fix the underlying cause.
I/flutter ( 4706): In either case, please report this assertion by filing a bug on GitHub:
I/flutter ( 4706): https://github.com/flutter/flutter/issues/new?template=BUG.md
I/flutter ( 4706):
I/flutter ( 4706): When the exception was thrown, this was the stack:
⣾I/flutter ( 4706): #2 RenderObject.layout (package:flutter/src/rendering/object.dart:1588:12)
I/flutter ( 4706): #3 RenderFlex.performLayout (package:flutter/src/rendering/flex.dart:737:15)
I/flutter ( 4706): #4 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #5 RenderPadding.performLayout (package:flutter/src/rendering/shifted_box.dart:199:11)
I/flutter ( 4706): #6 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #7 _RenderSingleChildViewport.performLayout (package:flutter/src/widgets/single_child_scroll_view.dart:497:13)
I/flutter ( 4706): #8 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #9 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #10 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #11 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #12 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #13 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #14 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #15 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #16 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #17 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #18 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #19 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #20 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #21 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #22 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #23 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #24 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #25 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #26 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #27 RenderPadding.performLayout (package:flutter/src/rendering/shifted_box.dart:199:11)
I/flutter ( 4706): #28 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #29 MultiChildLayoutDelegate.layoutChild (package:flutter/src/rendering/custom_layout.dart:142:11)
I/flutter ( 4706): #30 _ScaffoldLayout.performLayout (package:flutter/src/material/scaffold.dart:431:7)
I/flutter ( 4706): #31 MultiChildLayoutDelegate._callPerformLayout (package:flutter/src/rendering/custom_layout.dart:212:7)
I/flutter ( 4706): #32 RenderCustomMultiChildLayoutBox.performLayout (package:flutter/src/rendering/custom_layout.dart:356:14)
I/flutter ( 4706): #33 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #34 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #35 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #36 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #37 _RenderCustomClip.performLayout (package:flutter/src/rendering/proxy_box.dart:1206:11)
I/flutter ( 4706): #38 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #39 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #40 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #41 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #42 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #43 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #44 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #45 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #46 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #47 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #48 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #49 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #50 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #51 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #52 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #53 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #54 RenderOffstage.performLayout (package:flutter/src/rendering/proxy_box.dart:3015:13)
I/flutter ( 4706): #55 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #56 RenderStack.performLayout (package:flutter/src/rendering/stack.dart:510:15)
I/flutter ( 4706): #57 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #58 __RenderTheatre&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #59 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #60 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #61 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #62 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #63 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #64 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #65 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #66 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #67 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #68 _RenderProxyBox&RenderBox&RenderObjectWithChildMixin&RenderProxyBoxMixin.performLayout (package:flutter/src/rendering/proxy_box.dart:105:13)
I/flutter ( 4706): #69 RenderObject.layout (package:flutter/src/rendering/object.dart:1644:7)
I/flutter ( 4706): #70 RenderView.performLayout (package:flutter/src/rendering/view.dart:151:13)
I/flutter ( 4706): #71 RenderObject._layoutWithoutResize (package:flutter/src/rendering/object.dart:1519:7)
I/flutter ( 4706): #72 PipelineOwner.flushLayout (package:flutter/src/rendering/object.dart:766:18)
I/flutter ( 4706): #73 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding.drawFrame (package:flutter/src/rendering/binding.dart:347:19)
I/flutter ( 4706): #74 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding&WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:701:13)
I/flutter ( 4706): #75 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:286:5)
I/flutter ( 4706): #76 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1012:15)
I/flutter ( 4706): #77 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:952:9)
I/flutter ( 4706): #78 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.scheduleWarmUpFrame. (package:flutter/src/scheduler/binding.dart:773:7)
I/flutter ( 4706): #80 _Timer._runTimers (dart:isolate-patch/timer_impl.dart:382:19)
I/flutter ( 4706): #81 _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:416:5)
I/flutter ( 4706): #82 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:171:12)
I/flutter ( 4706): (elided 3 frames from class _AssertionError and package dart:async-patch)
I/flutter ( 4706):
I/flutter ( 4706): The following RenderObject was being processed when the exception was fired:
I/flutter ( 4706): RenderFlex#cefef relayoutBoundary=up13 NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 4706): creator: Column ← Padding ← Container ← _SingleChildViewport ← IgnorePointer-[GlobalKey#76138] ←
I/flutter ( 4706): Semantics ← Listener ← _GestureSemantics ←
I/flutter ( 4706): RawGestureDetector-[LabeledGlobalKey#101e8] ← Listener ← _ScrollableScope
I/flutter ( 4706): ← _ScrollSemantics-[GlobalKey#0c9fb] ← ⋯
I/flutter ( 4706): parentData: offset=Offset(0.0, 50.0) (can use size)
I/flutter ( 4706): constraints: BoxConstraints(0.0<=w<=360.0, 0.0<=h<=Infinity)
I/flutter ( 4706): size: Size(360.0, Infinity)
I/flutter ( 4706): direction: vertical
I/flutter ( 4706): mainAxisAlignment: start
I/flutter ( 4706): mainAxisSize: max
I/flutter ( 4706): crossAxisAlignment: center
I/flutter ( 4706): verticalDirection: down
I/flutter ( 4706): This RenderObject had the following descendants (showing up to depth 5):
I/flutter ( 4706): RenderPositionedBox#6e3a0 relayoutBoundary=up14 NEEDS-PAINT
I/flutter ( 4706): RenderPadding#1a1e4 relayoutBoundary=up15 NEEDS-PAINT
I/flutter ( 4706): RenderSemanticsAnnotations#fbe79 relayoutBoundary=up16 NEEDS-PAINT
I/flutter ( 4706): RenderImage#61f15 relayoutBoundary=up17 NEEDS-PAINT
I/flutter ( 4706): RenderOpacity#358ac relayoutBoundary=up14 NEEDS-PAINT
I/flutter ( 4706): RenderFlex#11e7c relayoutBoundary=up15 NEEDS-PAINT
I/flutter ( 4706): RenderPadding#2bd36 relayoutBoundary=up16 NEEDS-PAINT
I/flutter ( 4706): RenderSemanticsAnnotations#df18b relayoutBoundary=up17 NEEDS-PAINT
I/flutter ( 4706): RenderIgnorePointer#1cfed relayoutBoundary=up18 NEEDS-PAINT
I/flutter ( 4706): RenderPadding#2b351 relayoutBoundary=up16 NEEDS-PAINT
I/flutter ( 4706): RenderSemanticsAnnotations#e5b54 relayoutBoundary=up17 NEEDS-PAINT
I/flutter ( 4706): RenderIgnorePointer#c3687 relayoutBoundary=up18 NEEDS-PAINT
I/flutter ( 4706): RenderStack#40b20 relayoutBoundary=up14 NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 4706): RenderDecoratedBox#fac4c NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 4706): RenderFlex#3ca20 NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 4706): RenderPadding#54f30 NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 4706): RenderSemanticsAnnotations#8f362 NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 4706): RenderPadding#244f6 NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 4706): RenderSemanticsAnnotations#c84a8 NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 4706): RenderPadding#6c0ee NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 4706): RenderSemanticsAnnotations#5e14f NEEDS-LAYOUT NEEDS-PAINT
I/flutter ( 4706): ════════════════════════════════════════════════════════════════════════════════════════════════════
I/flutter ( 4706): Another exception was thrown: RenderPadding object was given an infinite size during layout.
I/flutter ( 4706): Another exception was thrown: NoSuchMethodError: The method '<=' was called on null.

Reloaded 2 of 523 libraries in 769ms.
`