Optional props: Type is not assignable to type 'IntrinsicAttributes & ...'.

Describe the bug I have a component like this:

<script lang="ts">
    export let width = "100%";
    export let height = "100px";

    export let responsive = false;
</script>

<div id="categorySelect" style="width: {width}; height: {height};" />

If I use this component from another component but do not define the width: <Abc height="100%" responsive={true} />, VSCode shows the following error:

Type '{ height: string; responsive: true; }' is not assignable to type 'IntrinsicAttributes & { width: string; height: string; responsive: boolean; }'.
  Property 'width' is missing in type '{ height: string; responsive: true; }' but required in type '{ width: string; height: string; responsive: boolean; }

Therefore I tried explicitly defining width as string | undefined:

<script lang="ts">
    export let width: string | undefined = "100%";
    export let height = "100px";

    export let responsive = false;
</script>

<div id="categorySelect" style="width: {width}; height: {height};" />

Now I get this error: Type 'true' is not assignable to type 'false' It complains because I am setting another value than the default value.

Most strangely, adding an event handler for an event which doesn’t even exist fixes the errors: <Abc height="100%" on:bla={e => {}} responsive={true} />

Expected behavior It should be possible to skip properties with default value or use other values than the default value.

System (please complete the following information):

• OS: Windows 10
• IDE: VSCode 1.47.2
• Plugin/Package: “Svelte for VSCode 101.3.0”

"svelte": "^3.24.0",
"svelte-check": "^0.1.55",
"svelte-loader": "^2.13.6",
"svelte-preprocess": "^4.0.8",
"@tsconfig/svelte": "^1.0.3",
"typescript": "^3.9.7",

tsconfig:

{
    "extends": "@tsconfig/svelte/tsconfig.json",
    "include": [
        "src/**/*",
        "src/node_modules"
    ],
    "exclude": [
        "node_modules/*",
        "dist/*"
    ],
    "compilerOptions": {
        "strict": true,
        "resolveJsonModule": true,
        "sourceMap": true
    }
}

Additional context This is so strange, maybe something with my setup is wrong? Related: #276

[dummdidumm]

Quick update: Of the three bugs only

• let a = false has a type of false, not boolean

still exists, which can be worked around by doing let a: boolean = false

[dummdidumm]

Closing in favor of #588