> For the complete documentation index, see [llms.txt](https://radlohead.gitbook.io/typescript-deep-dive/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://radlohead.gitbook.io/typescript-deep-dive/overview/checker/checker-global.md).

# Checker Diagnostics

Within `initializeTypeChecker` the following code exists:

```typescript
// Initialize global symbol table
forEach(host.getSourceFiles(), file => {
    if (!isExternalModule(file)) {
        mergeSymbolTable(globals, file.locals);
    }
});
```

Which basically merges all the `global` symbols into the `let globals: SymbolTable = {};` (in `createTypeChecker`) SymbolTable. `mergeSymbolTable` primarily calls `mergeSymbol`.