fix infer

Author: sumneko

script/vm/runner.lua

@@ -177,7 +177,7 @@ function mt:_compileBlock(block)
                 type  = 'save',
                 tag   = 'block',
                 copy  = true,
-                pos   = block.start,
+                pos   = childBlock.start,
             }
             local outStep = {
                 type  = 'save',

test/type_inference/init.lua

@@ -2191,3 +2191,29 @@ local x
 
 print(<?x?>)
 ]]
+
+TEST 'string' [[
+---@type string?
+local x
+
+if not x then
+    return
+else
+    print(<?x?>)
+end
+
+print(x)
+]]
+
+TEST 'string' [[
+---@type string?
+local x
+
+if not x then
+    return
+else
+    print(x)
+end
+
+print(<?x?>)
+]]