fix(datepicker): range selection strategy not picking up custom date adapter

src/material/datepicker/date-range-picker.ts

@@ -9,6 +9,7 @@
 import {ChangeDetectionStrategy, Component, ViewEncapsulation} from '@angular/core';
 import {MatDatepickerBase, MatDatepickerContent, MatDatepickerControl} from './datepicker-base';
 import {MAT_RANGE_DATE_SELECTION_MODEL_PROVIDER, DateRange} from './date-selection-model';
+import {MAT_CALENDAR_RANGE_STRATEGY_PROVIDER} from './date-range-selection-strategy';
 
 /**
  * Input that can be associated with a date range picker.
@@ -29,7 +30,10 @@ export interface MatDateRangePickerInput<D> extends MatDatepickerControl<D> {
   exportAs: 'matDateRangePicker',
   changeDetection: ChangeDetectionStrategy.OnPush,
   encapsulation: ViewEncapsulation.None,
-  providers: [MAT_RANGE_DATE_SELECTION_MODEL_PROVIDER]
+  providers: [
+    MAT_RANGE_DATE_SELECTION_MODEL_PROVIDER,
+    MAT_CALENDAR_RANGE_STRATEGY_PROVIDER,
+  ]
 })
 export class MatDateRangePicker<D> extends MatDatepickerBase<MatDateRangePickerInput<D>,
   DateRange<D>, D> {

src/material/datepicker/date-range-selection-strategy.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Injectable, InjectionToken} from '@angular/core';
+import {Injectable, InjectionToken, Optional, SkipSelf, FactoryProvider} from '@angular/core';
 import {DateAdapter} from '@angular/material/core';
 import {DateRange} from './date-selection-model';
 
@@ -70,3 +70,17 @@ export class DefaultMatCalendarRangeStrategy<D> implements MatDateRangeSelection
     return new DateRange<D>(start, end);
   }
 }
+
+
+/** @docs-private */
+export function MAT_CALENDAR_RANGE_STRATEGY_PROVIDER_FACTORY(
+  parent: MatDateRangeSelectionStrategy<unknown>, adapter: DateAdapter<unknown>) {
+  return parent || new DefaultMatCalendarRangeStrategy(adapter);
+}
+
+/** @docs-private */
+export const MAT_CALENDAR_RANGE_STRATEGY_PROVIDER: FactoryProvider = {
+  provide: MAT_DATE_RANGE_SELECTION_STRATEGY,
+  deps: [[new Optional(), new SkipSelf(), MAT_DATE_RANGE_SELECTION_STRATEGY], DateAdapter],
+  useFactory: MAT_CALENDAR_RANGE_STRATEGY_PROVIDER_FACTORY,
+};

src/material/datepicker/datepicker-module.ts

@@ -30,10 +30,6 @@ import {MatYearView} from './year-view';
 import {MatDateRangeInput} from './date-range-input';
 import {MatStartDate, MatEndDate} from './date-range-input-parts';
 import {MatDateRangePicker} from './date-range-picker';
-import {
-  MAT_DATE_RANGE_SELECTION_STRATEGY,
-  DefaultMatCalendarRangeStrategy
-} from './date-range-selection-strategy';
 
 
 @NgModule({
@@ -82,11 +78,7 @@ import {
   ],
   providers: [
     MatDatepickerIntl,
-    MAT_DATEPICKER_SCROLL_STRATEGY_FACTORY_PROVIDER,
-    {
-      provide: MAT_DATE_RANGE_SELECTION_STRATEGY,
-      useClass: DefaultMatCalendarRangeStrategy
-    }
+    MAT_DATEPICKER_SCROLL_STRATEGY_FACTORY_PROVIDER
   ],
   entryComponents: [
     MatDatepickerContent,

src/material/datepicker/public-api.ts

@@ -10,7 +10,11 @@ export * from './datepicker-module';
 export * from './calendar';
 export * from './calendar-body';
 export * from './datepicker';
-export * from './date-range-selection-strategy';
+export {
+  MAT_DATE_RANGE_SELECTION_STRATEGY,
+  MatDateRangeSelectionStrategy,
+  DefaultMatCalendarRangeStrategy,
+} from './date-range-selection-strategy';
 export * from './datepicker-animations';
 export {
   MAT_DATEPICKER_SCROLL_STRATEGY,