[inference] Capturing an immutable value should be a read
--- Following #1216: If a value is known to be immutable, then it doesn't need to be considered 'captured' since no mutation should occur. Couldn't figure out a unit test in which this specific fix matters, but we need this to fix test output of #1273 cc. @gsathya, would love some feedback / eyes on this. This makes sense for Primitives in particular (which are always read / copied in rval position), but I'm not as familiar with edge cases for other immutable values especially around lambdas.
Mofei Zhang committed
Feb 28, 2023 at 16:36 UTC
b532465ce293b01b0654fc509b4f3a322d2eab52
2 files changed
+7
-9
compiler/forget/src/Inference/InferReferenceEffects.ts
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@@ -308,7 +308,8 @@ class InferenceState {
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case Effect.Capture: {
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if (
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valueKind === ValueKind.Frozen ||
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- valueKind === ValueKind.MaybeFrozen
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+ valueKind === ValueKind.MaybeFrozen ||
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+ valueKind === ValueKind.Immutable
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) {
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effect = Effect.Read;
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} else {
compiler/forget/src/__tests__/fixtures/hir/destructure-capture-global.expect.md
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@@ -15,18 +15,15 @@ function component(a) {
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```javascript
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let someGlobal = {};
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function component(a) {
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- const $ = React.unstable_useMemoCache(3);
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- const t0 = someGlobal;
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+ const $ = React.unstable_useMemoCache(2);
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const c_0 = $[0] !== a;
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- const c_1 = $[1] !== t0;
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let x;
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- if (c_0 || c_1) {
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- x = { a: a, someGlobal: t0 };
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+ if (c_0) {
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+ x = { a: a, someGlobal: someGlobal };
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$[0] = a;
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- $[1] = t0;
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- $[2] = x;
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+ $[1] = x;
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} else {
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- x = $[2];
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+ x = $[1];
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}
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return x;
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}