stash

Author: sumneko

script/parser/compile.lua

@@ -3136,6 +3136,22 @@ local function parseGoTo()
     return action
 end
 
+local function parseFilter()
+    local exp = parseExp()
+    if exp then
+        local filter = {
+            type   = 'filter',
+            start  = exp.start,
+            finish = exp.finish,
+            exp    = exp,
+        }
+        exp.parent = filter
+        return filter
+    else
+        missExp()
+    end
+end
+
 local function parseIfBlock(parent)
     local ifLeft  = getPosition(Tokens[Index], 'left')
     local ifRight = getPosition(Tokens[Index] + 1, 'right')
@@ -3151,13 +3167,11 @@ local function parseIfBlock(parent)
         }
     }
     skipSpace()
-    local filter = parseExp()
+    local filter = parseFilter()
     if filter then
         ifblock.filter = filter
         ifblock.finish = filter.finish
         filter.parent = ifblock
-    else
-        missExp()
     end
     skipSpace()
     local thenToken = Tokens[Index + 1]
@@ -3210,13 +3224,11 @@ local function parseElseIfBlock(parent)
     }
     Index = Index + 2
     skipSpace()
-    local filter = parseExp()
+    local filter = parseFilter()
     if filter then
         elseifblock.filter = filter
         elseifblock.finish = filter.finish
         filter.parent = elseifblock
-    else
-        missExp()
     end
     skipSpace()
     local thenToken = Tokens[Index + 1]
@@ -3524,15 +3536,16 @@ local function parseWhile()
 
     skipSpace()
     local nextToken = Tokens[Index + 1]
-    local filter =  nextToken ~= 'do'
-                and nextToken ~= 'then'
-                and parseExp()
-    if filter then
-        action.filter = filter
-        action.finish = filter.finish
-        filter.parent = action
-    else
+    if nextToken == 'do'
+    or nextToken == 'then' then
         missExp()
+    else
+        local filter = parseFilter()
+        if filter then
+            action.filter = filter
+            action.finish = filter.finish
+            filter.parent = action
+        end
     end
 
     skipSpace()
@@ -3611,12 +3624,10 @@ local function parseRepeat()
         Index = Index + 2
 
         skipSpace()
-        local filter = parseExp()
+        local filter = parseFilter()
         if filter then
             action.filter = filter
             filter.parent = action
-        else
-            missExp()
         end
 
     else

script/parser/guide.lua

@@ -139,7 +139,8 @@ local childMap = {
     ['getfield']    = {'node', 'field'},
     ['list']        = {'#'},
     ['binary']      = {1, 2},
-    ['unary']       = {1},
+    ['unary']       = { 1 },
+    ['filter']      = {'exp'},
 
     ['doc']                = {'#'},
     ['doc.class']          = {'class', '#extends', '#signs', 'comment'},

script/vm/tracer.lua

@@ -102,21 +102,80 @@ function mt:getLastAssign(block, pos)
     return assign
 end
 
+---@param filter parser.object
+---@param node vm.node?
+---@return vm.node
+function mt:narrowByFilter(filter, node)
+    if not node then
+        node = vm.createNode()
+    end
+    if filter.type == 'filter' then
+        node = self:narrowByFilter(filter.exp, node)
+        return node
+    end
+    if filter.type == 'getlocal' then
+        if filter.node == self.source then
+            node = node:copy()
+            node:removeOptional()
+        end
+        return node
+    end
+    return node
+end
+
 ---@param source parser.object
 ---@return vm.node?
 function mt:calcNode(source)
+    if source.type == 'getlocal' then
+        return nil
+    end
+    if source.type == 'local' then
+        if source ~= self.source then
+            return nil
+        end
+    end
+    if source.type == 'setlocal' then
+        if source.node ~= self.source then
+            return nil
+        end
+    end
     if guide.isSet(source) then
         local node = vm.compileNode(source)
         return node
     end
     if source.type == 'do' then
         local lastAssign = self:getLastAssign(source, source.finish)
-        if lastAssign then
-            return self:getNode(lastAssign)
-        else
-            return nil
+        return self:getNode(lastAssign or source.parent)
+    end
+    if source.type == 'ifblock' then
+        local currentNode  = self:getNode(source.parent)
+        local narrowedNode = self:narrowByFilter(source.filter, currentNode)
+        return narrowedNode
+    end
+    if source.type == 'filter' then
+        local parent = source.parent
+        ---@type parser.object
+        local outBlock
+        if parent.type == 'ifblock' then
+            outBlock = parent.parent.parent
+            local lastAssign = self:getLastAssign(outBlock, parent.start)
+            return self:getNode(lastAssign or source.parent)
+        elseif parent.type == 'elseifblock' then
+            outBlock = parent.parent.parent
+            local lastAssign = self:getLastAssign(outBlock, parent.start)
+            return self:getNode(lastAssign or source.parent)
+        elseif parent.type == 'while' then
+            outBlock = parent.parent
+            local lastAssign = self:getLastAssign(outBlock, parent.start)
+            return self:getNode(lastAssign or source.parent)
+        elseif parent.type == 'repeat' then
+            outBlock = parent.parent
+            local lastAssign = self:getLastAssign(outBlock, parent.start)
+            return self:getNode(lastAssign or source.parent)
         end
+        assert(outBlock, parent.type)
     end
+    return nil
 end
 
 ---@param source parser.object
@@ -140,7 +199,7 @@ function mt:getNode(source)
         return node
     end
     local lastAssign = self:getLastAssign(parentBlock, source.start)
-    local parentNode = self:getNode(lastAssign or parentBlock)
+    local parentNode = self:getNode(lastAssign or source.parent)
     self.nodes[source] = parentNode or false
     return parentNode
 end

test/type_inference/init.lua

@@ -1829,6 +1829,17 @@ end
 print(<?x?>)
 ]]
 
+TEST 'nil' [[
+---@type integer?
+local x
+
+if not x then
+    print(<?x?>)
+end
+
+print(x)
+]]
+
 TEST 'integer' [[
 ---@type integer?
 local x