[compiler] Fix codegen for nested method calls with memoized properties #34100
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poteto
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| const items = makeArray(0, 1, 2, null, 4, false, 6); | ||
| t1 = Math; | ||
| t2 = t1.max; | ||
| t3 = 2; |
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this cache slot seems unnecessary
josephsavona
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Aug 4, 2025
...ges/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/codegen-methodcall.expect.md
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| // Reconstruct the MemberExpression if we previously saw an Identifier. | ||
| if (memberExpr.type === 'Identifier') { | ||
| const args = instrValue.args.map(arg => codegenArgument(cx, arg)); | ||
| value = createCallExpression( | ||
| cx.env, | ||
| memberExpr, | ||
| args, | ||
| instrValue.loc, | ||
| isHook, | ||
| ); |
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Hmmm, the invariant was there to make sure that we don't rewrite a method invocation, which may read from its receiver. In the Math.* cases they are static functions and that isn't a problem, but i'm wondering if the wrong signature could break compilation w the change as implemented.
I think it would be something that a) has the receiver as readonly and b) returns a primitive. Can you try constructing a method like this in shared-runtime and type it (shared-runtime-type-provider) to check that it works correctly?
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We received some bug reports about invariants reported by the compiler in their codebase. Adding them as repros. --- [//]: # (BEGIN SAPLING FOOTER) Stack created with [Sapling](https://sapling-scm.com). Best reviewed with [ReviewStack](https://reviewstack.dev/facebook/react/pull/34099). * #34100 * __->__ #34099
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When processing nested method calls like `Math.floor(diff.bar())`, the compiler would trigger an invariant that `MethodCall::property must be a MemberExpression but got an Identifier`. The issue occurred when the property (e.g., Math.floor) was memoized in a reactive scope and promoted to a named identifier. Later during codegen, retrieving this memoized temporary would return just an Identifier instead of the expected MemberExpression. The fix handles this case by checking if the property has been memoized as an Identifier and using it directly for the call expression, rather than requiring it to be a MemberExpression. This fixes two test cases that were previously failing.
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When processing nested method calls like
Math.floor(diff.bar()), the compiler would trigger an invariant thatMethodCall::property must be a MemberExpression but got an Identifier.The issue occurred when the property (e.g., Math.floor) was memoized in a reactive scope and promoted to a named identifier. Later during codegen, retrieving this memoized temporary would return just an Identifier instead of the expected MemberExpression.
The fix handles this case by checking if the property has been memoized as an Identifier and using it directly for the call expression, rather than requiring it to be a MemberExpression.
This fixes two test cases that were previously failing.