Christopher Chedeau
cf45afba61
- This brings in the flow test suite that contains a ton of JavaScript parsing edge cases - This creates snapshot tests using the pretty printer for all of them - If uncomment `RUN_AST_TESTS` line in `tests/run_specs.js`, it checks ast(pretty_print(x)) == ast(x). Right now, "178 failed, 197 passed, 375 of 377 total". So half of the tests are not passing, most of them are crashes and many of the rest are subtle issues.
28 lines
750 B
JavaScript
28 lines
750 B
JavaScript
/**
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* test handling of unaliased value assignment.
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*
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* An unaliased object rvalue may be assigned to a supertype lvalue,
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* because later widening mutations on the rvalue can't break assumptions
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* made by other lvalues.
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*
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* However, upon assignment the rvalue must take on the type of the
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* lvalue, to avoid both false positives and false negatives
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* (unsoundness), as shown below.
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*
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* @flow
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*/
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var glob: { x: string } = { x: "hey" };
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function assign_then_alias() {
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var obj: { x: string | number };
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obj = { x: "hey" };
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glob = obj; // error: subsequent assignment might make glob.x a number
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}
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function assign_then_widen() {
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var obj: { x: string | number };
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obj = { x: "hey" };
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obj.x = 10; // ok, by lvalue's given type
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}
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