update runner

3 files changed, 27 insertions, 0 deletions

diff --git a/script/vm/node.lua b/script/vm/node.lua
index 76e61192..5086f66d 100644
--- a/script/vm/node.lua
+++ b/script/vm/node.lua
@@ -2,6 +2,7 @@ local files    = require 'files'
 ---@class vm
 local vm       = require 'vm.vm'
 local ws       = require 'workspace.workspace'
+local guide    = require 'parser.guide'
 
 ---@type table<vm.object, vm.node>
 vm.nodeCache = {}
@@ -105,6 +106,18 @@ function mt:hasFalsy()
     return false
 end
 
+function mt:hasKnownType()
+    for _, c in ipairs(self) do
+        if c.type == 'global' and c.cate == 'type' then
+            return true
+        end
+        if guide.isLiteral(c) then
+            return true
+        end
+    end
+    return false
+end
+
 ---@return boolean
 function mt:isNullable()
     if self.optional then
diff --git a/script/vm/runner.lua b/script/vm/runner.lua
index 0ec26bef..a9c38a87 100644
--- a/script/vm/runner.lua
+++ b/script/vm/runner.lua
@@ -132,6 +132,7 @@ function mt:_lookInto(action, topNode, outNode)
         self:_launchBlock(action, blockNode:copy())
         topNode = mainNode
     elseif action.type == 'if' then
+        local hasElse
         local mainNode = topNode:copy()
         local blockNodes = {}
         for _, subBlock in ipairs(action) do
@@ -140,6 +141,7 @@ function mt:_lookInto(action, topNode, outNode)
                 blockNode, mainNode = self:_lookInto(subBlock.filter, blockNode, mainNode)
                 self:_fastWard(subBlock.filter.finish, blockNode)
             else
+                hasElse = true
                 mainNode:clear()
             end
             blockNode = self:_launchBlock(subBlock, blockNode:copy())
@@ -150,6 +152,9 @@ function mt:_lookInto(action, topNode, outNode)
                 blockNodes[#blockNodes+1] = blockNode
             end
         end
+        if not hasElse and not topNode:hasKnownType() then
+            mainNode:merge(vm.declareGlobal('type', 'unknown'))
+        end
         for _, blockNode in ipairs(blockNodes) do
             mainNode:merge(blockNode)
         end
diff --git a/test/type_inference/init.lua b/test/type_inference/init.lua
index a194ce2d..efcc5fea 100644
--- a/test/type_inference/init.lua
+++ b/test/type_inference/init.lua
@@ -2482,3 +2482,12 @@ t = t or {}
 
 print(<?t?>)
 ]]
+
+TEST 'unknown|nil' [[
+local x
+
+if x == nil then
+end
+
+print(<?x?>)
+]]