angular-cli compilation error + monorepo: error TS2451: Cannot redeclare block-scoped variable...

I have a monorepo set up with two packages. One is the main application, let's call it app, and the other is a shared library that the main application uses, let's call it lib. Both are TypeScript/Angular projects.

My folder structure looks like this:

monorepo/
packages/
app/
lib/


I am trying to configure the app project so that when it sees an import from the lib package, instead of going to node_modules I want it to go to the output directory from building the lib package. So I have in my tsconfig.json:

{
"compilerOptions": {
"baseUrl": ".",
"rootDir": ".",
"declaration": false,
"emitDecoratorMetadata": true,
"experimentalDecorators": true,
"lib": ["es7", "dom"],
"mapRoot": "./",
"module": "es2015",
"moduleResolution": "node",
"outDir": "../dist/out-tsc",
"sourceMap": true,
"target": "es5",
"typeRoots": [
"node_modules/@types"
],
"paths": {
"lib/*": ["../lib/dist/*"]
}
}


However, when I try to run ng build in the app folder, I get the following error messages (the same error twice, from two different locations):

ERROR in node_modules/@angular/core/src/render3/ng_dev_mode.d.ts(9,11): error TS2451: Cannot redeclare block-scoped variable 'ngDevMode'.
../lib/node_modules/@angular/core/src/render3/ng_dev_mode.d.ts(9,11): error TS2451: Cannot redeclare block-scoped variable 'ngDevMode'.


It's like it's trying to load Angular twice, one from the app directory and one from the lib directory.

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