fix tail call return value processing

src/test/res/tailcall.lua

@@ -0,0 +1,62 @@
+
+function a() 
+	return pcall( function() end )
+end
+
+function b() 
+	return pcall( function() print 'b' end )
+end
+
+function c() 
+	return pcall( function() return 'c' end )
+end
+
+print( pcall( a )  )
+print( pcall( b )  )
+print( pcall( c )  )
+
+local function sum(...)
+	local s = 0
+	for i,v in ipairs({...}) do
+		s = s + v
+	end
+	return s
+end
+
+local function f1(n,a,b,c)
+	local a = a or 0
+	local b = b or 0
+	local c = c or 0
+	if n <= 0 then 
+		return a,a+b,a+b+c
+	end
+	return f1(n-1,a,a+b,a+b+c)
+end
+
+local function f2(n,...)
+	if n <= 0 then 
+		return sum(...)
+	end
+	return f2(n-1,n,...)
+end
+
+local function f3(n,...)
+	if n <= 0 then 
+		return sum(...)
+	end
+	return pcall(f3,n-1,n,...)
+end
+
+local function all(f)
+	for n=0,3 do
+		t = {}
+		for m=1,5 do 
+			print( pcall( f, n, unpack(t)) )
+			t[m] = m
+		end
+	end
+end
+
+all(f1)
+all(f2)
+all(f3)