Keep the process.versions scan flag on the lowerer (#1579)

packages/compiler/src/frontend/lowering/builtins/process.ts

@@ -304,19 +304,13 @@ export function isOptionalProcessVersionsRead(lowerer: Lowerer, node: ts.Node):
   );
 }
 
-const mentionsVersions = new WeakMap<Lowerer, boolean>();
-
 /** Whether any implementation source spells `versions`. Programs that
  * never do skip the per-read checker queries above entirely. */
 function programMentionsVersions(lowerer: Lowerer): boolean {
-  let known = mentionsVersions.get(lowerer);
-  if (known === undefined) {
-    known = lowerer.program
-      .getImplementationSourceFiles()
-      .some((sf) => !sf.isDeclarationFile && sf.text.includes("versions"));
-    mentionsVersions.set(lowerer, known);
-  }
-  return known;
+  lowerer.mentionsProcessVersions ??= lowerer.program
+    .getImplementationSourceFiles()
+    .some((sf) => !sf.isDeclarationFile && sf.text.includes("versions"));
+  return lowerer.mentionsProcessVersions;
 }
 
 export function lowerProcessStreamProperty(

packages/compiler/src/frontend/lowering/lowerer.ts

@@ -1846,6 +1846,9 @@ export class Lowerer {
    * NaN, which lower to plain doubles (see nan-coded-reads.ts). Settled by
    * analyzeRuntimeOptionalArrayReads before any body lowers. */
   nanCodedReads: NanCodedReads | null = null;
+  /** Whether any implementation source spells `versions`
+   * (programMentionsVersions in builtins/process.ts). */
+  mentionsProcessVersions: boolean | undefined = undefined;
   private stringIndexBoundsCache: StringIndexBounds | null = null;
   /** Proofs that a string element read names an existing code unit. The
    * indexed-read analysis and expression lowering share one instance, so a