fix(builtin): wrap a uint64 converted to int in generic code

gs/builtin/builtin.ts

@@ -894,7 +894,8 @@ export function genericConvert<T>(
     case 'rune':
       return int(value, 32) as T
     case 'int':
-      return int(value) as T
+      // int is 64 bits, so a uint64 beyond its range wraps as in Go.
+      return int(value, 64) as T
     case 'uint8':
     case 'byte':
       return uint(value, 8) as T

tests/tests/generic_typeparam_conversion/expected.log

@@ -6,3 +6,5 @@
 10 wide
 16
 7 44
+-7 -7 -7
+-1

tests/tests/generic_typeparam_conversion/generic_typeparam_conversion.go

@@ -48,6 +48,12 @@ func toWide[T, E EnumConstraint](e E) T {
 	return T(e)
 }
 
+// fromUint64 converts a uint64 to a type parameter, which wraps a value
+// beyond the range of the type.
+func fromUint64[T Integer](u uint64) T {
+	return T(u)
+}
+
 // fromConst converts a constant and a basic value to a type parameter.
 func fromConst[T Integer](i int) (T, T) {
 	return T(7), T(i)
@@ -64,4 +70,7 @@ func main() {
 	println(int64(a) + int64(b))
 	c, d := fromConst[uint8](300)
 	println(c, d)
+	u := uint64(1<<64 - 7)
+	println(fromUint64[int](u), fromUint64[int64](u), fromUint64[int32](u))
+	println(fromUint64[int](u) % 3)
 }

tests/tests/generic_typeparam_conversion/generic_typeparam_conversion.gs.ts

@@ -115,6 +115,10 @@ export function toWide(__typeArgs: $.GenericTypeArgs | undefined, e: any): any {
 	return $.genericConvert<any>(__typeArgs, "T", e)
 }
 
+export function fromUint64(__typeArgs: $.GenericTypeArgs | undefined, u: bigint): any {
+	return $.genericConvert<any>(__typeArgs, "T", u)
+}
+
 export function fromConst(__typeArgs: $.GenericTypeArgs | undefined, i: number): [any, any] {
 	return [$.genericConvert<any>(__typeArgs, "T", 7), $.genericConvert<any>(__typeArgs, "T", i)]
 }
@@ -135,6 +139,9 @@ export async function main(): globalThis.Promise<void> {
 	let c: number = (__goscriptTuple1[0] as number)
 	let d: number = (__goscriptTuple1[1] as number)
 	await $.println(c, d)
+	let u = 18446744073709551609n
+	await $.println(fromUint64(__goscriptStatic4(), u), fromUint64(__goscriptStatic5(), u), fromUint64(__goscriptStatic6(), u))
+	await $.println(fromUint64(__goscriptStatic4(), u) % 3)
 }
 
 var __goscriptStatic0$value: any
@@ -157,6 +164,21 @@ function __goscriptStatic3(): any {
 	return __goscriptStatic3$value ??= ({[$.genericTypeArgsMarker]: $.genericTypeArgsBrand, T: { type: /* @__PURE__ */ $.basicType("uint8"), zero: () => 0 }})
 }
 
+var __goscriptStatic4$value: any
+function __goscriptStatic4(): any {
+	return __goscriptStatic4$value ??= ({[$.genericTypeArgsMarker]: $.genericTypeArgsBrand, T: { type: /* @__PURE__ */ $.basicType("int"), zero: () => 0 }})
+}
+
+var __goscriptStatic5$value: any
+function __goscriptStatic5(): any {
+	return __goscriptStatic5$value ??= ({[$.genericTypeArgsMarker]: $.genericTypeArgsBrand, T: { type: /* @__PURE__ */ $.basicType("int64"), zero: () => 0n }})
+}
+
+var __goscriptStatic6$value: any
+function __goscriptStatic6(): any {
+	return __goscriptStatic6$value ??= ({[$.genericTypeArgsMarker]: $.genericTypeArgsBrand, T: { type: /* @__PURE__ */ $.basicType("int32"), zero: () => 0 }})
+}
+
 if ($.isMainScript(import.meta)) {
 	await main()
 }