fix up sourcemap typings

src/Chunk.ts

@@ -1,6 +1,6 @@
 import { timeEnd, timeStart } from './utils/timers';
 import { decode } from 'sourcemap-codec';
-import MagicString, { Bundle as MagicStringBundle } from 'magic-string';
+import MagicString, { Bundle as MagicStringBundle, SourceMap } from 'magic-string';
 import { blank, forOwn } from './utils/object';
 import Module, { ModuleJSON } from './Module';
 import finalisers from './finalisers/index';
@@ -780,7 +780,7 @@ export default class Chunk {
 				if (footer) magicString.append('\n' + footer);
 
 				const prevCode = magicString.toString();
-				let map: RawSourceMap = null;
+				let map: SourceMap = null;
 				const bundleSourcemapChain: RawSourceMap[] = [];
 
 				return transformBundle(prevCode, this.graph.plugins, bundleSourcemapChain, options).then(

src/rollup/index.ts

@@ -21,6 +21,7 @@ import { Deprecation } from '../utils/deprecateOptions';
 import Graph from '../Graph';
 import { TransformContext } from '../utils/transform';
 import ensureArray from '../utils/ensureArray';
+import { SourceMap } from 'magic-string';
 
 export const VERSION = '<@VERSION@>';
 
@@ -246,7 +247,7 @@ export interface OutputChunk {
 	exports: string[];
 	modules: ModuleJSON[];
 
-	generate: (outputOptions: OutputOptions) => Promise<{ code: string; map: RawSourceMap }>;
+	generate: (outputOptions: OutputOptions) => Promise<{ code: string; map: SourceMap }>;
 	write: (options: OutputOptions) => Promise<void>;
 	getTimings?: () => SerializedTimings;
 }

src/utils/collapseSourcemaps.ts

@@ -4,6 +4,7 @@ import { basename, dirname, relative, resolve } from './path';
 import Module from '../Module';
 import { RawSourceMap } from 'source-map';
 import Chunk from '../Chunk';
+import { SourceMap } from 'magic-string';
 
 class Source {
 	isOriginal: boolean;
@@ -128,7 +129,7 @@ class Link {
 export default function collapseSourcemaps(
 	bundle: Chunk,
 	file: string,
-	map: RawSourceMap,
+	map: SourceMap,
 	modules: Module[],
 	bundleSourcemapChain: RawSourceMap[]
 ) {