Object.freeze after object creation doesn't error

TypeScript Version: 3.5.1

Search Terms: Object.freeze, freeze, freezing, properties, object, objects, property

Code

const a = Object.freeze({a: 0});
a.a = 1; // Error: Cannot assign read-only property

const b = {b: 0};
Object.freeze(b);
b.b = 1; // No error?

const c = {c: {d: 0}};
Object.freeze(c.c);
c.c.d = 1; // No error?

Expected behavior:

Cannot assign read-only property errors for the two lines with "No error?" above.

Actual behavior:

No errors

Playground Link: https://www.typescriptlang.org/play/?removeComments=true#code/MYewdgzgLgBAhjAvDA8gIwFYFNhQHQBmATllgF5YAUA3nAFwwAMAvgJQDcAUHHgsgIzsYAemEwAokSIgiDAMJwwYELDgQIASwDmYGCTgATALTgANgE8YAB2lWsRKOc6dQkWGiQxqaBiy7psXEIScio0Dk40PA8BIVEYADkQGHtpIgB+Z1doGGBPamAGagNfZmZ-TBx8YlIKSmA8YAiGhoNPQRExJJSpGXSgA

Reproduce the three Object.freeze examples in the linked TypeScript Playground and compare the diagnostics for each assignment. Trace the type-checking path that handles Object.freeze calls and verify the behavior against focused compiler tests. Done means both post-creation assignments produce the expected read-only-property error without regressing the first example.