Readd logic to accept the replacement if a block of the same type exi…

…sted in a given position

packages/block-editor/src/store/actions.js

@@ -230,6 +230,7 @@ export function* replaceBlocks( clientIds, blocks ) {
 		first( clientIds )
 	);
 	// Replace is valid if the new blocks can be inserted in the root block
+	// or if we had a block of the same type in the position of the block being replaced.
 	for ( let index = 0; index < blocks.length; index++ ) {
 		const block = blocks[ index ];
 		const canInsertBlock = yield select(
@@ -239,7 +240,12 @@ export function* replaceBlocks( clientIds, blocks ) {
 			rootClientId
 		);
 		if ( ! canInsertBlock ) {
-			return;
+			const clientIdToReplace = clientIds[ index ];
+			const nameOfBlockToReplace = clientIdToReplace &&
+				( yield select( 'core/block-editor', 'getBlockName', clientIdToReplace ) );
+			if ( ! nameOfBlockToReplace || ( nameOfBlockToReplace !== block.name ) ) {
+				return;
+			}
 		}
 	}
 	yield {

packages/block-editor/src/store/test/actions.js

@@ -215,7 +215,7 @@ describe( 'actions', () => {
 			} );
 		} );
 
-		it( 'should yield the REPLACE_BLOCKS action if the replacement is possible', () => {
+		it( 'should yield the REPLACE_BLOCKS action if the all the replacement blocks can be inserted in the parent block', () => {
 			const blocks = [ {
 				clientId: 'ribs',
 				name: 'core/test-ribs',
@@ -277,6 +277,66 @@ describe( 'actions', () => {
 				done: true,
 			} );
 		} );
+
+		it( 'should yield the REPLACE_BLOCKS if the block being replaced and the replacement are of the same type', () => {
+			const blocks = [ {
+				clientId: 'ribs',
+				name: 'core/test-block',
+			} ];
+
+			const replaceBlockGenerator = replaceBlocks( [ 'chicken' ], blocks );
+			expect(
+				replaceBlockGenerator.next().value,
+			).toEqual( {
+				args: [ 'chicken' ],
+				selectorName: 'getBlockRootClientId',
+				storeName: 'core/block-editor',
+				type: 'SELECT',
+			} );
+
+			expect(
+				replaceBlockGenerator.next().value,
+			).toEqual( {
+				args: [ 'core/test-block', undefined ],
+				selectorName: 'canInsertBlockType',
+				storeName: 'core/block-editor',
+				type: 'SELECT',
+			} );
+
+			expect(
+				replaceBlockGenerator.next( false ).value,
+			).toEqual( {
+				args: [ 'chicken' ],
+				selectorName: 'getBlockName',
+				storeName: 'core/block-editor',
+				type: 'SELECT',
+			} );
+
+			expect(
+				replaceBlockGenerator.next( 'core/test-block' ).value,
+			).toEqual( {
+				type: 'REPLACE_BLOCKS',
+				clientIds: [ 'chicken' ],
+				blocks,
+				time: expect.any( Number ),
+			} );
+
+			expect(
+				replaceBlockGenerator.next().value,
+			).toEqual( {
+				args: [],
+				selectorName: 'getBlockCount',
+				storeName: 'core/block-editor',
+				type: 'SELECT',
+			} );
+
+			expect(
+				replaceBlockGenerator.next( 1 ),
+			).toEqual( {
+				value: undefined,
+				done: true,
+			} );
+		} );
 	} );
 
 	describe( 'insertBlock', () => {