When defer blocks have a reference-based trigger without a parameter, we infer it from the placeholder block. This requires some validations like ensuring that there's only one element in the placeholder. The validations are currently implemented at the parser level which can affect tools like linters that need to pass `preserveWhitespaces: true` in order to get accurate source mappings.
These changes move the validations into the template type checker so that they still get flagged, but much later in the process. Moving them over involves a bit more work, because the template type checker also sets `preserveWhitespaces: true`.
Fixes#61725.
PR Close#61747
Adds a new diagnostic that ensures that a standalone component using custom structural directives in a template has the necessary imports for those directives.
Fixes#37322
PR Close#59443
The semantics for nullish coalescing (`??`) in Javascript/Typescript
differ slightly from the semantics in Angular templates. Mixing nullish
coalescing with logical and/or without parentheses is an error in
Javascript. This PR adds an extended diagnostic that can be enabled to
treat it as an error in Angular templates as well.
PR Close#60279
Adds a new diagnostic that ensures that a standalone component using custom structural directives in a template has the necessary imports for those directives.
Fixes#37322
PR Close#59443
Add the `strictStandalone` flag to `angularCompilerOptions`. When set to
true, the compiler will require that all declarations of components,
directive, and pipes be standalone. When `standalone: false` is provided,
an error is raised.
Note that until the default value of the standalone flag is flipped, this
does not catch the case where a declaration does not specify a value for
`standalone`.
The default value of the `strictStandalone` flag is `false`.
PR Close#57935
Adds a new diagnostic that will report cases where a declaration is in the `imports` array, but isn't being used anywhere. The diagnostic is reported as a warning by default and can be controlled using the following option in the tsconfig:
```
{
"angularCompilerOptions": {
"extendedDiagnostics": {
"checks": {
"unusedStandaloneImports": "suppress"
}
}
}
}
```
**Note:** I'll look into a codefix for the language service in a follow-up.
Fixes#46766.
PR Close#57605
Adds a new extended diagnostic that will flag `@let` declarations that aren't used within the template. The diagnostic can be turned off through the `extendedDiagnostics` compiler option.
PR Close#57033
Adds a new extended diagnostic that will flag `@let` declarations that aren't used within the template. The diagnostic can be turned off through the `extendedDiagnostics` compiler option.
PR Close#57033
Integrates let declarations into the template type checker by producing corresponding constants in the TCB.
This also includes a couple of custom diagnostics to flag usages of let before they're declared and illegal writes to let declarations. We can't rely on TS for these checks, because it includes the variable name in the diagnostic.
PR Close#56199
