Merge pull request #3394 from RomanSpector/fix/bitwise-operator-inference

fix: type inference for bitwise operators on integer variables

Author: sumneko

changelog.md

@@ -4,6 +4,8 @@
 <!-- Add all new changes here. They will be moved under a version at release -->
 * `CHG` Modified the `ResolveRequire` function to pass the source URI as a third argument.
 * `CHG` Improved the output of test failures during development
+* `FIX` Fix type inference for bitwise operators (`<<`, `>>`, `&`, `|`, `~`) on integer variables
+* `FIX` Fix constant value computation for chained bitwise expressions in hover tooltips
 * `FIX` Support Lua 5.5 prefix local attributes such as `local <close>x` and `local <const>x`
 
 ## 3.17.1

script/vm/operator.lua

@@ -58,6 +58,12 @@ vm.OP_UNARY_MAP  = util.revertMap(unaryMap)
 vm.OP_BINARY_MAP = util.revertMap(binaryMap)
 vm.OP_OTHER_MAP  = util.revertMap(otherMap)
 
+---@param source parser.object
+---@return uri, vm.infer, vm.infer
+local function getOperandInfers(source)
+    return guide.getUri(source), vm.getInfer(source[1]), vm.getInfer(source[2])
+end
+
 ---@param operators parser.object[]
 ---@param op string
 ---@param value? parser.object
@@ -267,6 +273,13 @@ vm.binarySwitch = util.switch()
             end
             if node then
                 vm.setNode(source, node)
+                return
+            end
+            -- Bitwise ops on integers always produce integer
+            local uri, infer1, infer2 = getOperandInfers(source)
+            if  infer1:hasType(uri, 'integer')
+            and infer2:hasType(uri, 'integer') then
+                vm.setNode(source, vm.declareGlobal('type', 'integer'))
             end
         end
     end)
@@ -386,9 +399,7 @@ vm.binarySwitch = util.switch()
                 [1]    = a .. b,
             })
         else
-            local uri = guide.getUri(source)
-            local infer1 = vm.getInfer(source[1])
-            local infer2 = vm.getInfer(source[2])
+            local uri, infer1, infer2 = getOperandInfers(source)
             if  (
                 infer1:hasType(uri, 'integer')
             or  infer1:hasType(uri, 'number')

script/vm/value.lua

@@ -118,6 +118,7 @@ function vm.getInteger(v)
     end
     local node = vm.compileNode(v)
     local result
+    local hasNonInteger = false
     for n in node:eachObject() do
         if n.type == 'integer' then
             if result then
@@ -135,7 +136,18 @@ function vm.getInteger(v)
             end
         elseif n.type ~= 'local'
         and    n.type ~= 'global' then
-            return nil
+            hasNonInteger = true
+        end
+    end
+    if hasNonInteger then
+        result = nil
+    end
+    -- If value not found via compiled node, try the local's
+    -- definition value directly (tracer may not preserve literals)
+    if result == nil and v.type == 'getlocal' then
+        local loc = v.node
+        if loc and loc.value then
+            return vm.getInteger(loc.value)
         end
     end
     return result

test/type_inference/common.lua

@@ -146,6 +146,16 @@ TEST 'integer' [[
 <?x?> = 1 << 2
 ]]
 
+TEST 'integer' [[
+local a = 1 << 20
+local <?b?> = a << 1
+]]
+
+TEST 'integer' [[
+local a = 1 << 20
+local <?b?> = (a << 1) - 1
+]]
+
 TEST 'unknown' [[
 <?x?> = a .. b
 ]]