More fixes to the import system and incremental compilation

src/frontend/compiler.nim

@@ -2014,20 +2014,23 @@ proc compile*(self: Compiler, ast: seq[Declaration], file: string, lines: seq[tu
     self.lines = lines
     self.source = source
     let pos = self.beginProgram(incremental)
-    if incremental:
+    if incremental and self.replMode:
         for i in countup(1, 2):
             discard self.chunk.code.pop()
     while not self.done():
         self.declaration(Declaration(self.step()))
     self.terminateProgram(pos, terminateScope)
     result = self.chunk
+    if incremental and not self.replMode:
+        for i in countup(1, 2):
+            discard self.chunk.code.pop()
 
 
 proc compileModule(self: Compiler, filename: string) =
     ## Compiles an imported module into an existing chunk.
     ## A temporary compiler object is initialized internally
     let path = joinPath(splitPath(self.file).head, filename)
-    if self.modules.containsOrIncl(path):
+    if self.modules.contains(path):
         return
     var lexer = newLexer()
     var parser = newParser()
@@ -2038,6 +2041,10 @@ proc compileModule(self: Compiler, filename: string) =
     let ast = parser.parse(tokens, filename, lexer.getLines(), source)
     compiler.names.add(self.names[0])
     discard compiler.compile(ast, filename, lexer.getLines(), source, chunk=self.chunk, incremental=true)
-    self.names &= compiler.names
+    for name in compiler.names:
+        if name.owner in self.modules:
+            continue
+        self.names.add(name)
+    self.modules.incl(path)
     self.closedOver &= compiler.closedOver
     compiler.endScope()