Backport "Count size of parameters for platform limit check" to LTS

compiler/src/dotty/tools/backend/jvm/BCodeSkelBuilder.scala

@@ -763,9 +763,14 @@ trait BCodeSkelBuilder extends BCodeHelpers {
       for (p <- params) { locals.makeLocal(p.symbol) }
       // debug assert((params.map(p => locals(p.symbol).tk)) == asmMethodType(methSymbol).getArgumentTypes.toList, "debug")
 
-      if (params.size > MaximumJvmParameters) {
+      val paramsSize = params.map { param =>
+        val tpeTym = param.symbol.info.typeSymbol
+        if tpeTym == defn.LongClass || tpeTym == defn.DoubleClass then 2 else 1
+      }.sum
+      if (paramsSize > MaximumJvmParameters) {
         // SI-7324
-        report.error(em"Platform restriction: a parameter list's length cannot exceed $MaximumJvmParameters.", ctx.source.atSpan(methSymbol.span))
+        val info = if paramsSize == params.length then "" else " (Long and Double count as 2)" // https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.3.3
+        report.error(em"Platform restriction: a parameter list's length cannot exceed $MaximumJvmParameters$info.", ctx.source.atSpan(methSymbol.span))
         return
       }
 

tests/neg/i18458.check

@@ -0,0 +1,4 @@
+-- Error: tests/neg/i18458.scala:1:4 -----------------------------------------------------------------------------------
+1 |def foo( // error
+  |    ^
+  |    Platform restriction: a parameter list's length cannot exceed 254 (Long and Double count as 2).

tests/neg/i18458.scala

@@ -0,0 +1,206 @@
+def foo( // error
+  foo1: Long,
+  foo2: Long,
+  foo3: Long,
+  foo4: Long,
+  foo5: Long,
+  foo6: Long,
+  foo7: Long,
+  foo8: Long,
+  foo9: Long,
+  foo10: Long,
+  foo11: Long,
+  foo12: Long,
+  foo13: Long,
+  foo14: Long,
+  foo15: Long,
+  foo16: Long,
+  foo17: Long,
+  foo18: Long,
+  foo19: Long,
+  foo20: Long,
+  foo21: Long,
+  foo22: Long,
+  foo23: Long,
+  foo24: Long,
+  foo25: Long,
+  foo26: Long,
+  foo27: Long,
+  foo28: Long,
+  foo29: Long,
+  foo30: Long,
+  foo31: Long,
+  foo32: Long,
+  foo33: Long,
+  foo34: Long,
+  foo35: Long,
+  foo36: Long,
+  foo37: Long,
+  foo38: Long,
+  foo39: Long,
+  foo40: Long,
+  foo41: Long,
+  foo42: Long,
+  foo43: Long,
+  foo44: Long,
+  foo45: Long,
+  foo46: Long,
+  foo47: Long,
+  foo48: Long,
+  foo49: Long,
+  foo50: Long,
+  foo51: Long,
+  foo52: Long,
+  foo53: Long,
+  foo54: Long,
+  foo55: Long,
+  foo56: Long,
+  foo57: Long,
+  foo58: Long,
+  foo59: Long,
+  foo60: Long,
+  foo61: Long,
+  foo62: Long,
+  foo63: Long,
+  foo64: Long,
+  foo65: Long,
+  foo66: Long,
+  foo67: Long,
+  foo68: Long,
+  foo69: Long,
+  foo70: Long,
+  foo71: Long,
+  foo72: Long,
+  foo73: Long,
+  foo74: Long,
+  foo75: Long,
+  foo76: Long,
+  foo77: Long,
+  foo78: Long,
+  foo79: Long,
+  foo80: Long,
+  foo81: Long,
+  foo82: Long,
+  foo83: Long,
+  foo84: Long,
+  foo85: Long,
+  foo86: Long,
+  foo87: Long,
+  foo88: Long,
+  foo89: Long,
+  foo90: Long,
+  foo91: Long,
+  foo92: Long,
+  foo93: Long,
+  foo94: Long,
+  foo95: Long,
+  foo96: Long,
+  foo97: Long,
+  foo98: Long,
+  foo99: Long,
+  foo100: Long,
+  foo101: Long,
+  foo102: Long,
+  foo103: Long,
+  foo104: Long,
+  foo105: Long,
+  foo106: Long,
+  foo107: Long,
+  foo108: Long,
+  foo109: Long,
+  foo110: Long,
+  foo111: Long,
+  foo112: Long,
+  foo113: Long,
+  foo114: Long,
+  foo115: Long,
+  foo116: Long,
+  foo117: Long,
+  foo118: Long,
+  foo119: Long,
+  foo120: Long,
+  foo121: Long,
+  foo122: Long,
+  foo123: Long,
+  foo124: Long,
+  foo125: Long,
+  foo126: Long,
+  foo127: Long,
+  foo128: Long,
+  foo129: Long,
+  foo130: Long,
+  foo131: Long,
+  foo132: Long,
+  foo133: Long,
+  foo134: Long,
+  foo135: Long,
+  foo136: Long,
+  foo137: Long,
+  foo138: Long,
+  foo139: Long,
+  foo140: Long,
+  foo141: Long,
+  foo142: Long,
+  foo143: Long,
+  foo144: Long,
+  foo145: Long,
+  foo146: Long,
+  foo147: Long,
+  foo148: Long,
+  foo149: Long,
+  foo150: Long,
+  foo151: Long,
+  foo152: Long,
+  foo153: Long,
+  foo154: Long,
+  foo155: Long,
+  foo156: Long,
+  foo157: Long,
+  foo158: Long,
+  foo159: Long,
+  foo160: Long,
+  foo161: Long,
+  foo162: Long,
+  foo163: Long,
+  foo164: Long,
+  foo165: Long,
+  foo166: Long,
+  foo167: Long,
+  foo168: Long,
+  foo169: Long,
+  foo170: Long,
+  foo171: Long,
+  foo172: Long,
+  foo173: Long,
+  foo174: Long,
+  foo175: Long,
+  foo176: Long,
+  foo177: Long,
+  foo178: Long,
+  foo179: Long,
+  foo180: Long,
+  foo181: Long,
+  foo182: Long,
+  foo183: Long,
+  foo184: Long,
+  foo185: Long,
+  foo186: Long,
+  foo187: Long,
+  foo188: Long,
+  foo189: Long,
+  foo190: Long,
+  foo191: Long,
+  foo192: Long,
+  foo193: Long,
+  foo194: Long,
+  foo195: Long,
+  foo196: Long,
+  foo197: Long,
+  foo198: Long,
+  foo199: Long,
+  foo200: Long
+) = foo1 + foo2
+
+@main
+def run =
+  println(foo(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200))