Bring parity to num/null (#2432)

Co-authored-by: wixoa <[email protected]>

Author: amylizzle

Content.Tests/DMProject/Tests/Operators/Division.dm

@@ -7,7 +7,7 @@
 	var/list/expected = list(
 		1,
 		"Error",
-		10,
+		"Error",
 		"Error",
 		"Error", // index 5
 		"Error",

Content.Tests/DMProject/Tests/Operators/div_by_null.dm

@@ -0,0 +1,3 @@
+// COMPILE ERROR OD0011
+/proc/RunTest
+	var/test = 10/null

Content.Tests/DMProject/Tests/Operators/valid_and_null.dm

@@ -57,7 +57,7 @@
 
 	ASSERT(C(4) / C(2) == C(2))
 	ASSERT(C(null) / C(2) == C(0))
-	ASSERT(C(2) / C(null) == C(2))
+	//ASSERT(C(2) / C(null) == C(2)) // Runtime error
 	ASSERT(C(null) / C(null) == C(0))
 
 	ASSERT(C(4) % C(3) == C(1))

Content.Tests/DMProject/Tests/Operators/valid_and_null_const.dm

@@ -30,8 +30,8 @@
 
 	ASSERT(C(4) / C(2) == C(2))
 	ASSERT(C(null) / C(2) == C(0))
-	ASSERT(C(2) / C(null) == C(2))
-	ASSERT(C(null) / C(null) == C(0))
+	//ASSERT(C(2) / C(null) == C(2)) //compile time error
+	//ASSERT(C(null) / C(null) == C(0))
 
 	ASSERT(C(4) % C(3) == C(1))
 	ASSERT(C(null) % C(3) == C(0))

DMCompiler/DM/Expressions/Binary.cs

@@ -116,6 +116,10 @@ public override bool TryAsConstant(DMCompiler compiler, [NotNullWhen(true)] out
 
         if (lhs is Number lhsNum && rhs is Number rhsNum) {
             constant = new Number(Location, lhsNum.Value / rhsNum.Value);
+        } else if (rhs is Null) {
+            compiler.Emit(WarningCode.BadExpression, Location, "Division by null is invalid");
+            constant = null;
+            return false;
         } else {
             constant = null;
             return false;

OpenDreamRuntime/Procs/DMOpcodeHandlers.cs

@@ -1163,8 +1163,7 @@ public static ProcStatus Divide(DMProcState state) {
                     state.Push(new DreamValue(0));
                     break;
                 case DreamValue.DreamValueType.Float when second.IsNull:
-                    state.Push(new DreamValue(first.MustGetValueAsFloat()));
-                    break;
+                    throw new Exception($"Attempted to divide {first} by null");
                 case DreamValue.DreamValueType.Float when second.Type == DreamValue.DreamValueType.Float:
                     var secondFloat = second.MustGetValueAsFloat();
                     if (secondFloat == 0) {