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Resolve evolving-array reads through the file's identifier index

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The evolving-array analysis walked the binding's whole function and
resolved the symbol of every identifier in it, once per empty-array
binding, so a function with many such bindings cost quadratic time. It now
takes the file's identifiers spelled like the binding from the per-file
index (identifiersNamed), keeps those inside the binding's function, and
resolves only them.
This commit is contained in:
Chris Tate
2026-10-21 04:19:04 -05:00
parent 009a01d074
commit 17db4cd443
1 changed files with 13 additions and 17 deletions
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packages/compiler/src/frontend/lowering/lower-stmts.ts
+13 -17
View File
@@ -202,6 +202,7 @@ import {
withRuntimeOptionalNarrowed,
} from "./lower-exprs.js";
import { globalSymbolKey } from "./expressions/global-symbols.js";
import { identifiersNamed } from "./identifier-uses.js";
import { lowerShortCircuitAssignment } from "./expressions/nullish-assignment.js";
import {
builtinGlobalValue,
@@ -4806,15 +4807,16 @@ function evolvingArrayType(lowerer: Lowerer, decl: ts.VariableDeclaration): IrTy
};
const scope = owner(decl);
let result: IrType | null = null;
let dynamic = false;
ts.walkPreorder(scope, (node) => {
if (dynamic) return "stop";
// The file's identifiers are indexed by name once (identifiersNamed), so
// each binding resolves only the uses spelled like it.
for (const node of identifiersNamed(lowerer, ts.getSourceFileOfNode(decl), decl.name.text)) {
if (
!ts.isIdentifier(node) ||
node === decl.name ||
node.pos < scope.pos ||
node.end > scope.end ||
lowerer.checker.getSymbolAtLocation(node) !== symbol
)
return undefined;
continue;
let target: ts.Node = node;
while (ts.isParenthesizedExpression(target.parent)) target = target.parent;
const parent = target.parent;
@@ -4823,21 +4825,15 @@ function evolvingArrayType(lowerer: Lowerer, decl: ts.VariableDeclaration): IrTy
parent.left === target &&
parent.operatorToken.kind >= ts.SyntaxKind.FirstAssignment &&
parent.operatorToken.kind <= ts.SyntaxKind.LastAssignment;
if (reassigned) {
dynamic = true;
return "stop";
}
if (reassigned) return DYN;
const t = lowerer.typeOf(node);
if (unsettled(t)) return undefined;
if (unsettled(t)) continue;
const mapped = lowerer.mapTypeOf(t);
if (!mapped || mapped.kind !== "array" || (result !== null && !typeEquals(result, mapped))) {
dynamic = true;
return "stop";
}
if (!mapped || mapped.kind !== "array" || (result !== null && !typeEquals(result, mapped)))
return DYN;
result = mapped;
return undefined;
});
return dynamic || result === null ? DYN : result;
}
return result ?? DYN;
}
/** A single static type for an initializer-less JavaScript `let` whose