refactor(checkbox): remove legacy property and support for legacy syntax

BREAKING.md

@@ -18,6 +18,7 @@ This is a comprehensive list of the breaking changes introduced in the major ver
 - [Global Styles](#version-8x-global-styles)
 - [Components](#version-8x-components)
   - [Button](#version-8x-button)
+  - [Checkbox](#version-8x-checkbox)
   - [Content](#version-8x-content)
   - [Datetime](#version-8x-datetime)
   - [Input](#version-8x-input)
@@ -140,6 +141,10 @@ For more information on the dynamic font, refer to the [Dynamic Font Scaling doc
 
 - Button text now wraps by default. If this behavior is not desired, add the `ion-text-nowrap` class from the [CSS Utilities](https://ionicframework.com/docs/layout/css-utilities).
 
+<h4 id="version-8x-checkbox">Checkbox</h4>
+
+ The `legacy` property and support for the legacy syntax, which involved placing an `ion-checkbox` inside of an `ion-item` with an `ion-label`, have been removed. For more information on migrating from the legacy checkbox syntax, refer to the [Checkbox documentation](https://ionicframework.com/docs/api/checkbox#migrating-from-legacy-checkbox-syntax).
+
 <h4 id="version-8x-content">Content</h4>
 
 - Content no longer sets the `--background` custom property when the `.outer-content` class is set on the host.

core/api.txt

@@ -297,7 +297,6 @@ ion-checkbox,prop,disabled,boolean,false,false,false
 ion-checkbox,prop,indeterminate,boolean,false,false,false
 ion-checkbox,prop,justify,"end" | "space-between" | "start",'space-between',false,false
 ion-checkbox,prop,labelPlacement,"end" | "fixed" | "stacked" | "start",'start',false,false
-ion-checkbox,prop,legacy,boolean | undefined,undefined,false,false
 ion-checkbox,prop,mode,"ios" | "md",undefined,false,false
 ion-checkbox,prop,name,string,this.inputId,false,false
 ion-checkbox,prop,value,any,'on',false,false

core/src/components.d.ts

@@ -630,10 +630,6 @@ export namespace Components {
           * Where to place the label relative to the checkbox. `"start"`: The label will appear to the left of the checkbox in LTR and to the right in RTL. `"end"`: The label will appear to the right of the checkbox in LTR and to the left in RTL. `"fixed"`: The label has the same behavior as `"start"` except it also has a fixed width. Long text will be truncated with ellipses ("..."). `"stacked"`: The label will appear above the checkbox regardless of the direction. The alignment of the label can be controlled with the `alignment` property.
          */
         "labelPlacement": 'start' | 'end' | 'fixed' | 'stacked';
-        /**
-          * Set the `legacy` property to `true` to forcibly use the legacy form control markup. Ionic will only opt checkboxes in to the modern form markup when they are using either the `aria-label` attribute or have text in the default slot. As a result, the `legacy` property should only be used as an escape hatch when you want to avoid this automatic opt-in behavior.  Note that this property will be removed in an upcoming major release of Ionic, and all form components will be opted-in to using the modern form markup.
-         */
-        "legacy"?: boolean;
         /**
           * The mode determines which platform styles to use.
          */
@@ -3639,7 +3635,6 @@ declare global {
         "ionChange": CheckboxChangeEventDetail;
         "ionFocus": void;
         "ionBlur": void;
-        "ionStyle": StyleEventDetail;
     }
     interface HTMLIonCheckboxElement extends Components.IonCheckbox, HTMLStencilElement {
         addEventListener<K extends keyof HTMLIonCheckboxElementEventMap>(type: K, listener: (this: HTMLIonCheckboxElement, ev: IonCheckboxCustomEvent<HTMLIonCheckboxElementEventMap[K]>) => any, options?: boolean | AddEventListenerOptions): void;
@@ -5323,10 +5318,6 @@ declare namespace LocalJSX {
           * Where to place the label relative to the checkbox. `"start"`: The label will appear to the left of the checkbox in LTR and to the right in RTL. `"end"`: The label will appear to the right of the checkbox in LTR and to the left in RTL. `"fixed"`: The label has the same behavior as `"start"` except it also has a fixed width. Long text will be truncated with ellipses ("..."). `"stacked"`: The label will appear above the checkbox regardless of the direction. The alignment of the label can be controlled with the `alignment` property.
          */
         "labelPlacement"?: 'start' | 'end' | 'fixed' | 'stacked';
-        /**
-          * Set the `legacy` property to `true` to forcibly use the legacy form control markup. Ionic will only opt checkboxes in to the modern form markup when they are using either the `aria-label` attribute or have text in the default slot. As a result, the `legacy` property should only be used as an escape hatch when you want to avoid this automatic opt-in behavior.  Note that this property will be removed in an upcoming major release of Ionic, and all form components will be opted-in to using the modern form markup.
-         */
-        "legacy"?: boolean;
         /**
           * The mode determines which platform styles to use.
          */
@@ -5347,10 +5338,6 @@ declare namespace LocalJSX {
           * Emitted when the checkbox has focus.
          */
         "onIonFocus"?: (event: IonCheckboxCustomEvent<void>) => void;
-        /**
-          * Emitted when the styles change.
-         */
-        "onIonStyle"?: (event: IonCheckboxCustomEvent<StyleEventDetail>) => void;
         /**
           * The value of the checkbox does not mean if it's checked or not, use the `checked` property for that.  The value of a checkbox is analogous to the value of an `<input type="checkbox">`, it's only used when the checkbox participates in a native `<form>`.
          */

core/src/components/checkbox/checkbox.ios.scss

@@ -31,21 +31,3 @@
 :host(.checkbox-disabled) {
   opacity: $checkbox-ios-disabled-opacity;
 }
-
-
-// iOS Checkbox Within An Item
-// TODO(FW-3100): remove this
-// -----------------------------------------
-
-:host(.in-item.legacy-checkbox) {
-  // end position by default
-  @include margin($checkbox-ios-item-end-margin-top, $checkbox-ios-item-end-margin-end, $checkbox-ios-item-end-margin-bottom, $checkbox-ios-item-end-margin-start);
-
-  display: block;
-
-  position: static;
-}
-
-:host(.in-item.legacy-checkbox[slot="start"]) {
-  @include margin($checkbox-ios-item-start-margin-top, $checkbox-ios-item-start-margin-end, $checkbox-ios-item-start-margin-bottom, $checkbox-ios-item-start-margin-start);
-}

core/src/components/checkbox/checkbox.ios.vars.scss

@@ -26,29 +26,5 @@ $checkbox-ios-icon-border-radius:         50% !default;
 /// @prop - Opacity of the disabled checkbox
 $checkbox-ios-disabled-opacity:           $form-control-ios-disabled-opacity !default;
 
-/// @prop - Margin top of the left checkbox item
-$checkbox-ios-item-start-margin-top:      8px !default;
-
-/// @prop - Margin end of the left checkbox item
-$checkbox-ios-item-start-margin-end:      $item-ios-padding-end !default;
-
-/// @prop - Margin bottom of the left checkbox item
-$checkbox-ios-item-start-margin-bottom:   $checkbox-ios-item-start-margin-top !default;
-
-/// @prop - Margin start of the left checkbox item
-$checkbox-ios-item-start-margin-start:    2px !default;
-
-/// @prop - Margin top of the right checkbox item
-$checkbox-ios-item-end-margin-top:        10px !default;
-
-/// @prop - Margin end of the right checkbox item
-$checkbox-ios-item-end-margin-end:        8px !default;
-
-/// @prop - Margin bottom of the right checkbox item
-$checkbox-ios-item-end-margin-bottom:     9px !default;
-
-/// @prop - Margin start of the right checkbox item
-$checkbox-ios-item-end-margin-start:      0 !default;
-
 /// @prop - Checkmark width of the checkbox icon
 $checkbox-ios-icon-checkmark-width:       1.5px !default;

core/src/components/checkbox/checkbox.md.scss

@@ -44,29 +44,10 @@
 // opacity set by its spec, while the label
 // should match the other form controls
 
-:host(.legacy-checkbox.checkbox-disabled),
 :host(.checkbox-disabled) .label-text-wrapper {
   opacity: $checkbox-md-disabled-opacity;
 }
 
 :host(.checkbox-disabled) .native-wrapper {
   opacity: $checkbox-md-icon-disabled-opacity;
 }
-
-
-// Material Design Checkbox Within An Item
-// TODO(FW-3100): remove this
-// --------------------------------------------------------
-
-:host(.in-item.legacy-checkbox) {
-  // end position by default
-  @include margin($checkbox-md-item-end-margin-top, $checkbox-md-item-end-margin-end, $checkbox-md-item-end-margin-bottom, $checkbox-md-item-end-margin-start);
-
-  display: block;
-
-  position: static;
-}
-
-:host(.in-item.legacy-checkbox[slot="start"]) {
-  @include margin($checkbox-md-item-start-margin-top, $checkbox-md-item-start-margin-end, $checkbox-md-item-start-margin-bottom, $checkbox-md-item-start-margin-start);
-}

core/src/components/checkbox/checkbox.md.vars.scss

@@ -30,30 +30,6 @@ $checkbox-md-transition-duration:        180ms !default;
 /// @prop - Transition easing of the checkbox
 $checkbox-md-transition-easing:          cubic-bezier(.4, 0, .2, 1) !default;
 
-/// @prop - Margin top of the start checkbox item
-$checkbox-md-item-start-margin-top:      18px !default;
-
-/// @prop - Margin end of the start checkbox item
-$checkbox-md-item-start-margin-end:      36px !default;
-
-/// @prop - Margin bottom of the start checkbox item
-$checkbox-md-item-start-margin-bottom:   $checkbox-md-item-start-margin-top !default;
-
-/// @prop - Margin start of the start checkbox item
-$checkbox-md-item-start-margin-start:    4px !default;
-
-/// @prop - Margin top of the end checkbox item
-$checkbox-md-item-end-margin-top:        18px !default;
-
-/// @prop - Margin end of the end checkbox item
-$checkbox-md-item-end-margin-end:        0 !default;
-
-/// @prop - Margin bottom of the end checkbox item
-$checkbox-md-item-end-margin-bottom:     $checkbox-md-item-end-margin-top !default;
-
-/// @prop - Margin start of the end checkbox item
-$checkbox-md-item-end-margin-start:      0 !default;
-
 /// @prop - Opacity of the disabled checkbox
 /// This value is used because the checkbox color is set to
 /// `rgb(0, 0, 0, 0.60)` when enabled and we need it to be

core/src/components/checkbox/checkbox.scss

@@ -48,34 +48,17 @@
  * toolbar which is why we do not
  * limit the below behavior to just ion-item.
  */
-:host([slot="start"]:not(.legacy-checkbox)),
-:host([slot="end"]:not(.legacy-checkbox)) {
+:host([slot="start"]),
+:host([slot="end"]) {
   width: auto;
 }
 
-// TODO(FW-3100): remove this
-:host(.legacy-checkbox) {
-  width: var(--size);
-  height: var(--size);
-}
-
 :host(.ion-color) {
   --checkbox-background-checked: #{current-color(base)};
   --border-color-checked: #{current-color(base)};
   --checkmark-color: #{current-color(contrast)};
 }
 
-// TODO(FW-3100): remove this
-:host(.legacy-checkbox) label {
-  @include input-cover();
-
-  display: flex;
-
-  align-items: center;
-
-  opacity: 0;
-}
-
 .checkbox-wrapper {
   display: flex;
 
@@ -96,7 +79,7 @@
   overflow: hidden;
 }
 
-:host(.in-item:not(.legacy-checkbox)) .label-text-wrapper {
+:host(.in-item) .label-text-wrapper {
   @include margin($checkbox-item-label-margin-top, null, $checkbox-item-label-margin-bottom, null);
 }
 
@@ -132,6 +115,9 @@ input {
 
   position: relative;
 
+  width: var(--size);
+  height: var(--size);
+
   transition: var(--transition);
 
   border-width: var(--border-width);
@@ -143,20 +129,6 @@ input {
   box-sizing: border-box;
 }
 
-// TODO(FW-3100): remove this
-:host(.legacy-checkbox) .checkbox-icon {
-  display: block;
-
-  width: 100%;
-  height: 100%;
-}
-
-// TODO(FW-3100): merge this with other .checkbox-icon styles above
-:host(:not(.legacy-checkbox)) .checkbox-icon {
-  width: var(--size);
-  height: var(--size);
-}
-
 .checkbox-icon path {
   fill: none;
   stroke: var(--checkmark-color);