diff --git a/packages/compiler/src/frontend/lowering/containers/replacer-params.ts b/packages/compiler/src/frontend/lowering/containers/replacer-params.ts
index e84ca1461..3a3eff1cf 100644
--- a/packages/compiler/src/frontend/lowering/containers/replacer-params.ts
+++ b/packages/compiler/src/frontend/lowering/containers/replacer-params.ts
@@ -115,7 +115,10 @@ const STRING_MEMBERS: ReadonlySet<string> = new Set([
 
 /** Whether every read of `symbol` in `body` is one that means the same
  * for an `any` value and for a `kind` value, and lowers for both: a
- * template span, a Number/String/parseInt/parseFloat argument, a listed
+ * template span, the argument of Number or String, the text argument of
+ * parseInt or parseFloat for a string and the radix of parseInt for a
+ * number (each a parameter of that type, which an `any` value converts
+ * to), a listed
  * string member, `+`, strict equality, arithmetic and comparisons of
  * numbers, a returned value, and a string key of an element access on a
  * string-indexed record or an `any` value. Anything else keeps the
@@ -144,13 +147,20 @@ function readsFit(
       return shape?.indexValue !== undefined && !shape.tuple;
     }
     if (ts.isArrowFunction(parent)) return parent.body === node;
-    if (ts.isCallExpression(parent))
-      return (
-        parent.expression !== node &&
-        ["Number", "String", "parseInt", "parseFloat"].some((global) =>
-          lowerer.isStdlibGlobal(parent.expression, global),
-        )
-      );
+    if (ts.isCallExpression(parent)) {
+      if (parent.expression === node) return false;
+      const position = parent.arguments.nodes.indexOf(node as ts.Expression);
+      if (
+        lowerer.isStdlibGlobal(parent.expression, "Number") ||
+        lowerer.isStdlibGlobal(parent.expression, "String")
+      )
+        return position === 0;
+      if (lowerer.isStdlibGlobal(parent.expression, "parseFloat"))
+        return position === 0 && kind === "string";
+      if (lowerer.isStdlibGlobal(parent.expression, "parseInt"))
+        return position === 0 ? kind === "string" : position === 1 && kind === "f64";
+      return false;
+    }
     if (ts.isPropertyAccessExpression(parent)) {
       const member = parent.name.text;
       if (kind !== "string" || parent.expression !== node || !STRING_MEMBERS.has(member))
diff --git a/packages/compiler/test/replacer-params.test.ts b/packages/compiler/test/replacer-params.test.ts
index bb5549a86..a5d22bb82 100644
--- a/packages/compiler/test/replacer-params.test.ts
+++ b/packages/compiler/test/replacer-params.test.ts
@@ -69,6 +69,8 @@ console.log(text.replace(/(a)|(b)/g, (m, a, b) => \`\${m}\${a}\${b}\`));
 console.log(text.replace(/(a)(b)?/g, (m: string, a: string, b: string | undefined, at: number) => m + a + (b ?? "") + at));
 const half = (n: number): number => n / 2;
 console.log(text.replace(/b/g, (m, at) => String(half(at))));
+console.log(text.replace(/b/g, (m, at) => String(parseFloat(at) + parseInt(at))));
+console.log(text.replace(/(\\d)/g, (m, d) => String(parseInt("11", d))));
 console.log(text.replace(/(a)(b)(c)/g, (m, a, b, c, at, all, extra) => m + a + b + c + at + all + extra));
 `);
     expect(replacerCalls(llvm)).toEqual({
@@ -76,7 +78,10 @@ console.log(text.replace(/(a)(b)(c)/g, (m, a, b, c, at, all, extra) => m + a + b
       // two captures a match can leave unset (bits 1 and 2);
       // \`string | undefined\` at capture 2 (bit 8 + 2); an offset passed to a
       // number parameter keeps its checked-dynamic box (bit 1).
-      direct: ["2:0", "2:-2147483648", "3:6", "4:1024", "2:2"],
+      // parseFloat and parseInt take text, and parseInt's radix is a
+      // number: the offset passed as text and the capture passed as the
+      // radix stay checked-dynamic (bit 1), so both calls compile.
+      direct: ["2:0", "2:-2147483648", "3:6", "4:1024", "2:2", "2:2", "2:2"],
       // Seven parameters exceed the direct calls' limit.
       boxed: 1,
     });
diff --git a/tests/corpus/8345-replace-callback-untyped-params.ts b/tests/corpus/8345-replace-callback-untyped-params.ts
index 31d3a038b..18ddb3389 100644
--- a/tests/corpus/8345-replace-callback-untyped-params.ts
+++ b/tests/corpus/8345-replace-callback-untyped-params.ts
@@ -51,6 +51,11 @@ console.log("ab".replace(/(?<a>a)|(?<b>b)/g, (m, a, b, at, all, groups) => `${m}
 console.log("ab".replace(/b/, (m, at, all, extra, more) => `${m}:${at}:${all}:${extra}:${more}`));
 console.log("ab".replace(/(a)(b)/, (m, a, b, at, all, extra, more) => `${m}${a}${b}${at}${all}${extra}${more}`));
 
+// An offset passed to parseFloat converts with ToString, and captures
+// passed to parseInt and parseFloat are their text.
+console.log("a1b22".replace(/\d+/g, (m, at) => `<${parseFloat(at) + parseInt(m, at + 10)}>`));
+console.log("1.5 2e1".replace(/(\S+)/g, (_m, d) => String(parseFloat(d) + parseInt(d) + Number(d))));
+
 // Results that are not strings convert with ToString.
 const counts: Record<string, any> = { a: 1, b: true, c: null, d: undefined, e: { toString: () => "E" } };
 console.log("a b c d e".replace(/\w/g, (m) => counts[m]));