fix(lsp): 别名点号导入逐段高亮

import a.b.c as x 的路径段先于别名写入出现点，避免顺序倒置被丢弃；模块路径段即使解析不到模块也保持 namespace，便于识别缺失依赖。

App/lib/lsp/LspSemantic.vp

@@ -287,10 +287,14 @@ def _TokenForOcc(ctx: LspSemCtx*, pool: memhub.MemManager*,
                     typ = _TypeForTarget(tw)
                     mods = _ModsForTarget(tw)
     if typ < 0:
-        # Builtin type names have no declaration; color them like class types.
-        if o.builtin_type == 0:
-            return None
-        typ = ST_CLASS
+        if o.module_path != 0:
+            # Dotted import segments stay namespaced even when the module cannot be found.
+            typ = ST_NAMESPACE
+        else:
+            # Builtin type names have no declaration; color them like class types.
+            if o.builtin_type == 0:
+                return None
+            typ = ST_CLASS
     tok: LspSemToken* = _NewTok(pool, o.line, o.sc, o.line, o.ec, typ)
     if tok is not None:
         tok.mods = mods

App/lib/lsp/LspSymbols.vp

@@ -93,6 +93,8 @@ class LspOccurrence:
     force_module: int
     # 1 when the name is an unresolved builtin type (int/str/list/...), 0 otherwise.
     builtin_type: int
+    # 1 for a segment of a dotted module path (always a namespace, even when the module is absent).
+    module_path: int
 
     def __new__(self, pool: memhub.MemManager*) -> rawptr:
         p: LspOccurrence* = (LspOccurrence*)(pool.alloc(LspOccurrence.__sizeof__()))
@@ -954,6 +956,7 @@ def _AddModulePathOccs(pool: memhub.MemManager*, a: LspAnalysis*, scope: LspScop
                 o: LspOccurrence* = _AddOcc(pool, a, scope, name, lineno, col + start,
                                             int(string.strlen(name)), ast.ASTCtx.Load, 0)
                 if o is not None:
+                    o.module_path = 1
                     if start == 0:
                         o.sym = head
                         o.head = head
@@ -1260,11 +1263,12 @@ def _WalkStmt(pool: memhub.MemManager*, a: LspAnalysis*, scope: LspScope*,
                     if sym is not None:
                         sym.import_kind = LSP_IMPORT_MODULE
                         sym.import_mod = bound_mod
-                    _DeclImportOcc(pool, a, scope, al, bound, sym)
                     if al.asname is not None:
                         _AddModulePathOccs(pool, a, scope, al.lineno, al.col_offset,
                                            al.name, 0, 0, None)
+                        _DeclImportOcc(pool, a, scope, al, bound, sym)
                     else:
+                        _DeclImportOcc(pool, a, scope, al, bound, sym)
                         _AddModulePathOccs(pool, a, scope, al.lineno, al.col_offset,
                                            al.name, 0, 1, sym)
                 i += 1

Tools/lsp/fixtures/gate10_use.vp

@@ -5,6 +5,8 @@ from .gate10_stub import StubThing
 from .gate10_extra import *
 import gate10_types
 import gate10_pkg.sub.mod
+import gate10_pkg.sub as pkgsub
+import ghost_lib.path
 
 
 def star_use(e: Extra) -> int:

Tools/lsp/probe.py

@@ -1545,6 +1545,30 @@ def gate10(exe: str) -> int:
         if not got.endswith(suffix):
             raise AssertionError(f"dotted import definition target is wrong: {pos} -> {got}")
 
+    alias_line = _position(text, "import gate10_pkg.sub as pkgsub")
+    for delta, segment in ((7, "gate10_pkg"), (18, "sub"), (25, "pkgsub")):
+        pos = {"line": alias_line["line"], "character": alias_line["character"] + delta}
+        if not _find_token(sem_tokens, pos["line"], pos["character"],
+                           sem_types.index("namespace")):
+            raise AssertionError(f"aliased dotted import is not highlighted: {segment} {pos}")
+    alias_sub = {"line": alias_line["line"], "character": alias_line["character"] + 18}
+    alias_def = client.request(
+        "textDocument/definition",
+        {"textDocument": {"uri": uri}, "position": alias_sub},
+        timeout=120.0,
+    ).get("result")
+    if not isinstance(alias_def, list) or not alias_def:
+        raise AssertionError(f"aliased dotted import definition failed: {alias_def}")
+    if not alias_def[0]["uri"].replace("\\", "/").endswith("gate10_pkg/sub/__init__.vp"):
+        raise AssertionError(f"aliased dotted import target is wrong: {alias_def}")
+
+    ghost_line = _position(text, "import ghost_lib.path")
+    for delta, segment in ((7, "ghost_lib"), (17, "path")):
+        pos = {"line": ghost_line["line"], "character": ghost_line["character"] + delta}
+        if not _find_token(sem_tokens, pos["line"], pos["character"],
+                           sem_types.index("namespace")):
+            raise AssertionError(f"unresolved module path is not highlighted: {segment} {pos}")
+
     def at(needle: str, delta: int = 0, occurrence: int = 0) -> dict[str, int]:
         pos = _position(text, needle, occurrence)
         pos["character"] += delta