symmetry : elseBlocks updated twice

[sparecycles]

Just viewing the output tab of https://svelte.technology/repl/?gist=0a4d409dcea5883c47167a55965f03d9

The last line of the update function contains an update of the elseBlock after rendering (or if the elseBlock was already instantiated then it will be updated an additional time).

		update: function ( changed, root ) {
			if ( root.foo ) {
				if ( !ifBlock_0 ) {
					ifBlock_0 = renderIfBlock_0( root, component, target, ifBlock_0_anchor );
				} else {
					ifBlock_0.update( changed, root );
				}
				
				if ( elseBlock_0 ) {
					elseBlock_0.teardown( true );
					elseBlock_0 = null;
				}
			}
			
			else {
				if ( ifBlock_0 ) {
					ifBlock_0.teardown( true );
					ifBlock_0 = null;
				}
				
				if ( !elseBlock_0 ) {
					elseBlock_0 = renderElseBlock_0( root, component, target, ifBlock_0_anchor );
				} else {
					elseBlock_0.update( changed, root );
				}
			}
			if ( elseBlock_0 ) elseBlock_0.update( changed, root );
		},

Consider deleting this line?

svelte/compiler/generate/visitors/IfBlock.js

Line 83 in b63a54b

update += `\nif ( ${elseName} ) ${elseName}.update( changed, ${generator.current.params} );`;

[Rich-Harris]

This has now been addressed separately via #28