Fix return inside switch case

Fixes #2783

data/expression2/tests/regressions/2783.txt

@@ -0,0 +1,20 @@
+## SHOULD_PASS:EXECUTE
+
+function number test(N:number) {
+    switch (N) {
+        case 1,
+            return 5
+        case 3,
+            error("unreachable")
+        case 2,
+            return 2
+        case 5,
+            error("unreachable")
+    }
+
+    return 1
+}
+
+assert( test(1) == 5 )
+assert( test(2) == 2 )
+assert( test(4) == 1 )

lua/entities/gmod_wire_expression2/base/compiler.lua

@@ -536,24 +536,26 @@ local CompileVisitors = {
 
 		return function(state) ---@param state RuntimeContext
 			local expr = expr(state)
-
 			state:PushScope()
+
 			for i = 1, ncases do
 				local case = cases[i]
 				if case[1](state, expr) ~= 0 then
 					case[2](state)
 
 					if state.__break__ then
 						state.__break__ = false
-						state:PopScope()
-						return
+						goto exit
+					elseif state.__return__ then -- Yes this should only be checked if the switch is inside a function, but I don't care enough about the performance of switch case to add another duplicated 30 lines to the file
+						goto exit
 					else -- Fallthrough, run every case until break found.
 						for j = i + 1, ncases do
 							cases[j][2](state)
 							if state.__break__ then
 								state.__break__ = false
-								state:PopScope()
-								return
+								goto exit
+							elseif state.__return__ then
+								goto exit
 							end
 						end
 					end
@@ -564,6 +566,7 @@ local CompileVisitors = {
 				default(state)
 			end
 
+			::exit::
 			state:PopScope()
 		end
 	end,