refactor(material/core): update minimum required sass version and clean up workarounds

Updates the minimum required version of Sass and cleans up some workarounds for `list.slash` and `math.div`.

BREAKING CHANGE:
* Material now requires at least version 1.34.0 of Sass. Version 1.38.0 is recommended.

Fixes #22915.

Author: crisbeto

package.json

@@ -215,7 +215,7 @@
     "rollup-plugin-commonjs": "^10.1.0",
     "rollup-plugin-node-resolve": "^5.2.0",
     "rollup-plugin-sourcemaps": "^0.6.3",
-    "sass": "^1.34.1",
+    "sass": "^1.38.0",
     "selenium-webdriver": "^3.6.0",
     "semver": "^7.3.4",
     "send": "^0.17.1",

src/material-experimental/mdc-card/card.scss

@@ -1,5 +1,5 @@
+@use 'sass:math';
 @use '@material/card' as mdc-card;
-@use '../../material/core/style/private';
 @use '../mdc-helpers/mdc-helpers';
 
 // TODO(jelbourn): move header and title-group styles to their own files.
@@ -44,7 +44,7 @@ $mat-card-default-padding: 16px !default;
   // When a subtitle is inside of a header, we want to move it up slightly to reduce the space with
   // the title, and add a margin bottom to create space underneath the header.
   .mat-mdc-card-subtitle {
-    margin-top: -(private.private-div($mat-card-default-padding, 2));
+    margin-top: -(math.div($mat-card-default-padding, 2));
     margin-bottom: $mat-card-default-padding;
   }
 }

src/material-experimental/mdc-form-field/_form-field-density.scss

@@ -1,8 +1,8 @@
+@use 'sass:map';
+@use 'sass:math';
 @use '@material/density' as mdc-density;
 @use '@material/textfield' as mdc-textfield;
-@use 'sass:map';
 @use '../../material/core/theming/theming';
-@use '../../material/core/style/private';
 @use 'form-field-sizing';
 
 // Mixin that sets the vertical spacing for the infix container of filled form fields.
@@ -55,7 +55,7 @@
   // cannot update the spacing to explicit numbers based on the density scale. Instead, we
   // determine the height reduction and equally subtract it from the default `top` and `bottom`
   // padding that is provided by the Material Design specification.
-  $vertical-deduction: private.private-div(mdc-textfield.$height - $height, 2);
+  $vertical-deduction: math.div(mdc-textfield.$height - $height, 2);
   // Map that describes the padding for form-fields with label.
   $with-label-padding: (
     top: form-field-sizing.$mat-form-field-with-label-input-padding-top - $vertical-deduction,
@@ -78,7 +78,7 @@
   // form-field because we do not know what type of form-field control is set up. Hence
   // we always use a fixed position for the label. This does not have any implications.
   .mat-mdc-form-field .mat-mdc-text-field-wrapper .mdc-floating-label {
-    top: private.private-div($height, 2);
+    top: math.div($height, 2);
   }
 
   // For the outline appearance, we re-create the active floating label transform. This is

src/material-experimental/mdc-form-field/_form-field-native-select.scss

@@ -1,8 +1,8 @@
 @use 'sass:map';
+@use 'sass:math';
 @use '../mdc-helpers/mdc-helpers';
 @use '../../cdk/a11y';
 @use '../../material/core/theming/palette';
-@use '../../material/core/style/private';
 @use '@material/theme/theme-color' as mdc-theme-color;
 
 // Width of the Material Design form-field select arrow.
@@ -66,8 +66,8 @@ $mat-form-field-select-horizontal-end-padding: $mat-form-field-select-arrow-widt
       content: '';
       width: 0;
       height: 0;
-      border-left: private.private-div($mat-form-field-select-arrow-width, 2) solid transparent;
-      border-right: private.private-div($mat-form-field-select-arrow-width, 2) solid transparent;
+      border-left: math.div($mat-form-field-select-arrow-width, 2) solid transparent;
+      border-right: math.div($mat-form-field-select-arrow-width, 2) solid transparent;
       border-top: $mat-form-field-select-arrow-height solid;
       position: absolute;
       right: 0;

src/material-experimental/mdc-select/select.scss

@@ -1,8 +1,8 @@
+@use 'sass:math';
 @use '@material/menu-surface' as mdc-menu-surface;
 @use '@material/list/evolution-mixins' as mdc-list;
 @use '../../material/core/style/variables';
 @use '../../material/core/style/vendor-prefixes';
-@use '../../material/core/style/private';
 @use '../../cdk/a11y';
 
 $mat-select-arrow-size: 5px !default;
@@ -111,7 +111,7 @@ $scale: 0.75 !default;
   // Delay the transition until the label has animated about a third of the way through, in
   // order to prevent the placeholder from overlapping for a split second.
   transition: color variables.$swift-ease-out-duration
-      private.private-div(variables.$swift-ease-out-duration, 3)
+      math.div(variables.$swift-ease-out-duration, 3)
       variables.$swift-ease-out-timing-function;
 
   ._mat-animation-noopable & {
@@ -143,7 +143,7 @@ $scale: 0.75 !default;
     }
 
     .mdc-floating-label--float-above {
-      $arrow-scale: private.private-div($mat-select-placeholder-arrow-space, $scale);
+      $arrow-scale: math.div($mat-select-placeholder-arrow-space, $scale);
       max-width: calc(100% / #{$scale} - #{$arrow-scale});
     }
   }

src/material-experimental/mdc-slide-toggle/slide-toggle.scss

@@ -1,11 +1,11 @@
 @use 'sass:map';
+@use 'sass:math';
 @use '@material/switch/switch' as mdc-switch;
 @use '@material/switch/switch-theme' as mdc-switch-theme;
 @use '@material/form-field' as mdc-form-field;
 @use '@material/ripple' as mdc-ripple;
 @use '../mdc-helpers/mdc-helpers';
 @use '../../material/core/style/layout-common';
-@use '../../material/core/style/private';
 @use '../../cdk/a11y';
 
 @include mdc-form-field.core-styles($query: mdc-helpers.$mat-base-styles-query);
@@ -66,6 +66,6 @@
     // Usually 1px would be enough, but MDC reduces the opacity on the
     // element so we need to make this a bit more prominent.
     outline: solid 2px;
-    outline-offset: private.private-div(map.get(mdc-switch-theme.$light-theme, track-height), 2);
+    outline-offset: math.div(map.get(mdc-switch-theme.$light-theme, track-height), 2);
   }
 }

src/material/badge/_badge-theme.scss

@@ -4,10 +4,10 @@
 @use 'sass:color';
 @use 'sass:map';
 @use 'sass:meta';
+@use 'sass:math';
 @use '../core/theming/theming';
 @use '../core/typography/typography';
 @use '../core/typography/typography-utils';
-@use '../core/style/private';
 @use '../../cdk/a11y';
 
 $font-size: 12px;
@@ -29,13 +29,13 @@ $_badge-structure-emitted: false !default;
 
   &.mat-badge-above {
     .mat-badge-content {
-      top: private.private-div(-$size, 2);
+      top: math.div(-$size, 2);
     }
   }
 
   &.mat-badge-below {
     .mat-badge-content {
-      bottom: private.private-div(-$size, 2);
+      bottom: math.div(-$size, 2);
     }
   }
 
@@ -68,27 +68,27 @@ $_badge-structure-emitted: false !default;
   &.mat-badge-overlap {
     &.mat-badge-before {
       .mat-badge-content {
-        left: private.private-div(-$size, 2);
+        left: math.div(-$size, 2);
       }
     }
 
     [dir='rtl'] &.mat-badge-before {
       .mat-badge-content {
         left: auto;
-        right: private.private-div(-$size, 2);
+        right: math.div(-$size, 2);
       }
     }
 
     &.mat-badge-after {
       .mat-badge-content {
-        right: private.private-div(-$size, 2);
+        right: math.div(-$size, 2);
       }
     }
 
     [dir='rtl'] &.mat-badge-after {
       .mat-badge-content {
         right: auto;
-        left: private.private-div(-$size, 2);
+        left: math.div(-$size, 2);
       }
     }
   }

src/material/card/card.scss

@@ -1,3 +1,4 @@
+@use 'sass:math';
 @use '../core/style/variables';
 @use '../core/style/elevation';
 @use '../core/style/private';
@@ -59,8 +60,8 @@ $header-size: 40px !default;
 
 .mat-card-actions {
   @extend %mat-card-section-base;
-  margin-left: private.private-div(-$padding, 2);
-  margin-right: private.private-div(-$padding, 2);
+  margin-left: math.div(-$padding, 2);
+  margin-right: math.div(-$padding, 2);
   padding: 8px 0;
 }
 

src/material/checkbox/checkbox.scss

@@ -18,7 +18,7 @@ $_ripple-radius: 20px;
 $_item-spacing: variables.$toggle-padding;
 
 // The width of the line used to draw the checkmark / mixedmark.
-$_mark-stroke-size: private.private-div(2, 15) * checkbox-common.$size !default;
+$_mark-stroke-size: math.div(2, 15) * checkbox-common.$size !default;
 
 
 // Fades in the background of the checkbox when it goes from unchecked -> {checked,indeterminate}.

src/material/core/option/option.scss

@@ -1,7 +1,7 @@
+@use 'sass:math';
 @use '../style/menu-common';
 @use '../style/vendor-prefixes';
 @use '../style/layout-common';
-@use '../style/private';
 @use '../../../cdk/a11y';
 
 .mat-option {
@@ -78,7 +78,7 @@
 }
 
 .mat-option-pseudo-checkbox {
-  $margin: private.private-div(menu-common.$side-padding, 2);
+  $margin: math.div(menu-common.$side-padding, 2);
   margin-right: $margin;
 
   [dir='rtl'] & {

src/material/core/selection/pseudo-checkbox/pseudo-checkbox.scss

@@ -1,3 +1,4 @@
+@use 'sass:math';
 @use '../../style/checkbox-common';
 @use '../../style/private';
 @use '../../style/variables';
@@ -50,20 +51,20 @@ $_checkmark-size: checkbox-common.$size - (2 * $_padding);
 }
 
 .mat-pseudo-checkbox-indeterminate::after {
-  top: private.private-div(checkbox-common.$size - checkbox-common.$border-width, 2) -
+  top: math.div(checkbox-common.$size - checkbox-common.$border-width, 2) -
       checkbox-common.$border-width;
-  left: private.private-div(checkbox-common.$border-width, 2);
+  left: math.div(checkbox-common.$border-width, 2);
   width: checkbox-common.$size - 6px;
   opacity: 1;
   border-radius: 2px;
 }
 
 .mat-pseudo-checkbox-checked::after {
-  top: private.private-div(checkbox-common.$size, 2) - private.private-div($_checkmark-size, 4) -
-      private.private-div(checkbox-common.$size, 10) - checkbox-common.$border-width;
+  top: math.div(checkbox-common.$size, 2) - math.div($_checkmark-size, 4) -
+       math.div(checkbox-common.$size, 10) - checkbox-common.$border-width;
   left: $_padding - checkbox-common.$border-width * 1.5;
   width: $_checkmark-size;
-  height: private.private-div($_checkmark-size - checkbox-common.$border-width, 2);
+  height: math.div($_checkmark-size - checkbox-common.$border-width, 2);
   border-left: checkbox-common.$border-width solid currentColor;
   transform: rotate(-45deg);
   opacity: 1;

src/material/core/style/_private.scss

@@ -1,7 +1,4 @@
 @use 'sass:map';
-@use 'sass:math';
-@use 'sass:meta';
-@use 'sass:list';
 @use './elevation';
 
 @mixin private-theme-elevation($zValue, $config, $opacity: elevation.$opacity) {
@@ -42,27 +39,3 @@
     @content;
   }
 }
-
-// Private polyfill for the `math.div` function from Sass to be used until we can update the
-// minimum required Sass version to 1.34.0 or above.
-// TODO(crisbeto): replace with `math.div` eventually.
-@function private-div($a, $b) {
-  @if (meta.function-exists('div', 'math')) {
-    @return math.div($a, $b);
-  }
-  @else {
-    @return $a / $b;
-  }
-}
-
-// Private polyfill for the `list.slash` function from Sass to be used until we can update the
-// minimum required Sass version to 1.34.0 or above.
-// TODO(crisbeto): replace with `list.slash` eventually.
-@function private-slash($a, $b) {
-  @if (meta.function-exists('slash', 'list')) {
-    @return list.slash($a, $b);
-  }
-  @else {
-    @return #{$a}#{' / '}#{$b};
-  }
-}

src/material/core/typography/_typography-utils.scss

@@ -3,7 +3,6 @@
 @use 'sass:math';
 @use 'sass:meta';
 @use 'sass:string';
-@use '../style/private';
 
 
 // Utility for fetching a nested value from a typography config.
@@ -78,10 +77,8 @@
     font-family: $font-family;
   }
   @else {
-    // Otherwise use the shorthand `font`, because it's the least amount of bytes. Note
-    // that we need to use `list.slash` for `font-size/line-height` in order to prevent
-    // Sass from dividing the two values.
-    font: $font-weight private.private-slash($font-size, $line-height) $font-family;
+    // Otherwise use the shorthand `font`, because it's the least amount of bytes.
+    font: $font-weight list.slash($font-size, $line-height) $font-family;
   }
 }
 

src/material/datepicker/calendar-body.scss

@@ -1,12 +1,12 @@
-@use '../core/style/private';
+@use 'sass:math';
 @use '../../cdk/a11y';
 
 $calendar-body-label-padding-start: 5% !default;
 // We don't want the label to jump around when we switch between month and year views, so we use
 // the same amount of padding regardless of the number of columns. We align the header label with
 // the one third mark of the first cell, this was chosen somewhat arbitrarily to make it look
 // roughly like the mock. Half way is too far since the cell text is center aligned.
-$calendar-body-label-side-padding: private.private-div(33%, 7) !default;
+$calendar-body-label-side-padding: math.div(33%, 7) !default;
 $calendar-body-cell-min-size: 32px !default;
 $calendar-body-cell-content-margin: 5% !default;
 $calendar-body-cell-content-border-width: 1px !default;

src/material/datepicker/date-range-input.scss

@@ -1,14 +1,14 @@
+@use 'sass:math';
 @use '../core/style/variables';
 @use '../core/style/vendor-prefixes';
-@use '../core/style/private';
 @use '../../cdk/a11y';
 
 $date-range-input-separator-spacing: 4px;
 $date-range-input-part-max-width: calc(50% - #{$date-range-input-separator-spacing});
 
 @mixin _placeholder-transition($property) {
   transition: #{$property} variables.$swift-ease-out-duration
-    private.private-div(variables.$swift-ease-out-duration, 3)
+    math.div(variables.$swift-ease-out-duration, 3)
     variables.$swift-ease-out-timing-function;
 }
 

src/material/form-field/_form-field-fill-theme.scss

@@ -1,8 +1,8 @@
 @use 'sass:map';
+@use 'sass:math';
 @use '../core/theming/theming';
 @use '../core/typography/typography';
 @use '../core/typography/typography-utils';
-@use '../core/style/private';
 
 
 // Theme styles that only apply to the fill appearance of the form-field.
@@ -55,7 +55,7 @@ $fill-dedupe: 0;
 @mixin _label-floating($font-scale, $infix-padding, $infix-margin-top) {
   transform: translateY(-$infix-margin-top - $infix-padding + $fill-dedupe)
              scale($font-scale);
-  width: private.private-div(100%, $font-scale) + $fill-dedupe;
+  width: math.div(100%, $font-scale) + $fill-dedupe;
 
   $fill-dedupe: $fill-dedupe + 0.00001 !global;
 }