[ASDAlexander77]

const n = 5; delete n; compiled with no diagnostic. mlirGen(DeleteExpression) did fail ("the operand of a 'delete' operator must be optional"), but mlirGen(Expression) dropped its result, so the postponed error was never shown.

Fix:

• the delete's failure now reaches the statement;
• a bare identifier that is no class instance, array or new value gets TypeScript's message: The operand of a 'delete' operator must be a property reference (this covers let n = 5 and a string local too).

Repro (diagnostic-location/delete_local.ts):

class C {}

function main() {
    const c = new C();
    delete c;          // still fine: frees the instance
    const n = 5;
    delete n;          // 9:5: error: The operand of a 'delete' operator must be a property reference
}

A second dropped error, now fixed (rc/own): after delete c of a variable with storage, the null stored into its slot (so the release at scope exit does nothing, see the comment there) went through a cast that failed the strict-null check, so the store was never emitted. Propagating the failure exposed this: 00owned_delete.ts under rc and own_err_delete.ts failed. That internal cast now skips the strict-null check, so the store is made. Under -mm=own, own_err_delete reaches its intended "'delete' is not supported by -mm=own yet" error again.

ctest -C Release -j 8 --timeout 300: 100% passed, 0 failed (4092 tests on this branch).

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