Sizeof alignof fixes (#9568)

fixes #9545

compiler/sizealignoffsetimpl.nim

@@ -122,7 +122,7 @@ proc computeObjectOffsetsFoldFunction(conf: ConfigRef; n: PNode, initialOffset:
     let size = n.sym.typ.size
     let align = n.sym.typ.align
     result.align = align
-    if initialOffset == szUnknownSize:
+    if initialOffset == szUnknownSize or size == szUnknownSize:
       n.sym.offset = szUnknownSize
       result.offset = szUnknownSize
     else:

tests/misc/tsizeof.nim

@@ -350,5 +350,19 @@ testinstance:
 
   main()
 
+{.emit: """/*TYPESECTION*/
+typedef struct{
+  float a; float b;
+} Foo;
+""".}
+
+type
+  Foo {.importc.} = object
+
+  Bar = object
+    b: byte
+    foo: Foo
+
+assert sizeof(Bar) == 12
 
 echo "OK"