Name functions stored in JavaScript object literals as Node (#1591)

packages/compiler/src/frontend/lowering/expressions/object-literals.ts

@@ -20,7 +20,7 @@ import type { IrExpr, IrLocal, IrRecordShape, IrStmt, IrType, SrcLoc } from "../
 import { isCjsExportTableLiteral, isJsSourceFile, locOf } from "../../program.js";
 import { NARROW_FIRST } from "../surfaces.js";
 import { recordShapeMismatchDiag } from "../../../diagnostics/diagnostic.js";
-import { PoisonError, neverTaintedJsType } from "../lowerer.js";
+import { PoisonError, jsFuncNameOf, neverTaintedJsType } from "../lowerer.js";
 import type { Lowerer } from "../lowerer.js";
 import { lowerIndexMergeHelper } from "../containers/indexed-objects.js";
 import type { IndexMergeContributor } from "../containers/indexed-objects.js";
@@ -188,6 +188,16 @@ function propNameText(lowerer: Lowerer, name: ts.PropertyName): string {
   return (name as ts.Identifier | ts.StringLiteral).text;
 }
 
+/** The name an anonymous function or a method takes from its property key
+ * (NamedEvaluation): an identifier, string or numeric key, or a computed
+ * key that folds to one string. Null for other keys. */
+function propertyFunctionName(lowerer: Lowerer, name: ts.PropertyName): string | null {
+  if (ts.isComputedPropertyName(name)) return literalComputedKey(lowerer, name);
+  if (ts.isNumericLiteral(name)) return String(Number(name.text));
+  if (ts.isIdentifier(name) || ts.isStringLiteral(name)) return name.text;
+  return null;
+}
+
 /** The runtime-keyed JS object literal (a computed key that doesn't fold):
  * builds a dyn object member-by-member. Keys evaluate before their values,
  * properties in source order — JS's object-literal evaluation exactly.
@@ -406,6 +416,26 @@ export function lowerDynObjectLiteral(
     let v = boxValue
       ? boxValue(valueExpr as ts.Expression, raw)
       : lowerer.coerceToExpected(raw, DYN);
+    // A function that boxes into a property takes its name as Node gives
+    // it: a function read by name keeps that name (`{ f }`, `{ k: f }`),
+    // and an anonymous function or a method takes the property's name
+    // (`{ g: function () {} }`, `{ m() {} }`).
+    if (
+      !boxValue &&
+      v.kind === "dynFrom" &&
+      v.value.type.kind === "func" &&
+      v.fnName === undefined
+    ) {
+      let anonymous: ts.Node = valueExpr;
+      while (ts.isParenthesizedExpression(anonymous)) anonymous = anonymous.expression;
+      const name =
+        ts.isMethodDeclaration(prop) ||
+        ((ts.isFunctionExpression(anonymous) || ts.isArrowFunction(anonymous)) &&
+          !(ts.isFunctionExpression(anonymous) && anonymous.name))
+          ? propertyFunctionName(lowerer, prop.name!)
+          : jsFuncNameOf(valueExpr, lowerer);
+      if (name !== null) v = { ...v, fnName: name };
+    }
     // A JS object's array-valued properties retain the same source array.
     // Repeated references must compare equal and mutations remain shared.
     if (

packages/compiler/test/ts7/baselines/order-parity/tests/corpus/6760-object-literal-function-names.cjs.json

@@ -0,0 +1,6 @@
+{
+ "order": [
+  "<repo>/tests/corpus/6760-object-literal-function-names.cjs"
+ ],
+ "diags": []
+}

tests/corpus/6760-object-literal-function-names.cjs

@@ -0,0 +1,29 @@
+'use strict';
+// A function stored in an object literal's property keeps the name Node
+// gives it: a function read by name keeps that name, and an anonymous
+// function, arrow or method takes the property's key.
+function f() {}
+const g = function () {};
+const h = () => 1;
+const named = function inner() {};
+const o = {
+  f,
+  g,
+  h,
+  k: f,
+  anon: function () {},
+  arrow: () => 2,
+  'a-b': () => 3,
+  ['computed']: () => 4,
+  m() {},
+  named,
+  inline: function own() {},
+};
+for (const key of Object.keys(o)) console.log(key, JSON.stringify(o[key].name));
+console.log(o);
+const mixed = { n: 1, s: 'x', f, g: function () {} };
+console.log(mixed, mixed.g.name);
+function show(value) {
+  console.log(value);
+}
+show({ f, m() {} });

tests/harness/corpus-costs/6760-object-literal-function-names.cjs.json

@@ -0,0 +1 @@
+{ "plain": 2630, "san": 3350 }