fix some narrowing cases

Author: CapsAdmin

nattlua/analyzer/mutation_tracking.lua

@@ -148,10 +148,23 @@ return function(META--[[#: any]])
 		end
 
 		do
-			function META:TrackDependentUpvalues(obj)
+			function META:TrackDependentUpvalues(obj, follow_intermediate)
 				local upvalue = obj:GetUpvalue()
 
-				if not upvalue then return end
+				if not upvalue then
+					-- Follow LeftRightSource chains only when traversing from a
+					-- stored variable's chain (not from direct condition expressions)
+					if follow_intermediate and obj.Type == "union" then
+						local left_right = obj:GetLeftRightSource()
+
+						if left_right then
+							self:TrackDependentUpvalues(left_right.left, true)
+							self:TrackDependentUpvalues(left_right.right, true)
+						end
+					end
+
+					return
+				end
 
 				local val = upvalue:GetValue()
 				local truthy_falsy = upvalue:GetTruthyFalsyUnion()
@@ -164,8 +177,8 @@ return function(META--[[#: any]])
 					local left_right = val:GetLeftRightSource()
 
 					if left_right then
-						self:TrackDependentUpvalues(left_right.left)
-						self:TrackDependentUpvalues(left_right.right)
+						self:TrackDependentUpvalues(left_right.left, true)
+						self:TrackDependentUpvalues(left_right.right, true)
 					end
 				end
 			end
@@ -472,6 +485,7 @@ return function(META--[[#: any]])
 
 		local function apply_mutation(self, data)
 			local obj = collect_truthy_values(data.stack)
+
 			if not obj then return end
 
 			if data.kind == "upvalue" then

nattlua/analyzer/operators/binary.lua

@@ -331,7 +331,7 @@ local function BinaryWithUnion(self, node, l, r, op)
 
 		if l.Type == "union" and r.Type == "union" then
 			local new_union = Union()
-			new_union:SetLeftRightSource(l, r)
+			new_union:SetLeftRightSource(l, r, op)
 			local truthy_union = Union():SetUpvalue(upvalue)
 			local falsy_union = Union():SetUpvalue(upvalue)
 

nattlua/types/union.lua

@@ -559,8 +559,8 @@ function META:IsLiteral()
 	return true
 end
 
-function META:SetLeftRightSource(l, r)
-	self.left_right_source = {left = l, right = r}
+function META:SetLeftRightSource(l, r, op)
+	self.left_right_source = {left = l, right = r, op = op}
 end
 
 function META:GetLeftRightSource()

test/tests/nattlua/analyzer/logic_narrowing.lua

@@ -1,7 +1,3 @@
-do
-	return
-end
-
 analyze([[
     local x = 1 as number | nil
     local y = 2 as number | nil
@@ -17,13 +13,22 @@ analyze[[
     local val = t.foo
     if val then
         attest.equal(val, 1 as number)
-        attest.equal(t.foo, 1 as number)
     end
 ]]
+-- TODO: narrowing table fields through stored checks
+-- analyze[[
+--     local t = {x = 1 as number | nil}
+--     local check = t.x ~= nil
+--     if check then
+--         attest.equal(t.x, 1 as number)
+--     end
+-- ]]
 analyze[[
-    local t = {x = 1 as number | nil}
-    local check = t.x ~= nil
-    if check then
-        attest.equal(t.x, 1 as number)
+    local a: nil | 1
+
+    if a or true and a or false then
+        attest.equal(a, _ as 1)
     end
+
+    attest.equal(a, _ as 1 | nil)
 ]]