What problem does this feature solve?

Could be used like:

import * as compiler from "@vue/compiler-sfc";
const source: string = "<template>Hello World</template>";
const parsed: compiler.SFCParseResult = compiler.parse(source);

Instead of:

import * as compiler from "@vue/compiler-sfc";
const source: string = "<template>Hello World</template>";
const { descriptor, errors }: { descriptor: compiler.SFCDescriptor, errors: (compiler.CompilerError | SyntaxError)[] } = compiler.parse(source);

What does the proposed API look like?

N/A