[clang-tools-extra] [clangd] Harden incomingCalls() against possible misinterpretation of a range as pertaining to the wrong file (PR #111616)

[Nathan Ridge via cfe-commits]

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@@ -2292,9 +2289,26 @@ incomingCalls(const CallHierarchyItem &Item, const SymbolIndex *Index) {
   Index->lookup(ContainerLookup, [&](const Symbol &Caller) {
     auto It = CallsIn.find(Caller.ID);
     assert(It != CallsIn.end());
-    if (auto CHI = symbolToCallHierarchyItem(Caller, Item.uri.file()))
+    if (auto CHI = symbolToCallHierarchyItem(Caller, Item.uri.file())) {
+      SymbolLocation CallerLoc =
+          Caller.Definition ? Caller.Definition : Caller.CanonicalDeclaration;
+      std::vector<Range> FromRanges;
+      for (const SymbolLocation &L : It->second) {
+        if (StringRef{L.FileURI} != StringRef{CallerLoc.FileURI}) {
+          elog("incomingCalls: call location not in same file as caller, this "
+               "is unexpected");
+          continue;
+        }
+        Range R;
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HighCommander4 wrote:

Note: I didn't use `indexToLSPLocation()` here because the `URI::resolve` operation that it does seems like unnecessary work here. I could factor out the part that converts the range into a function to avoid duplicating it here.

https://github.com/llvm/llvm-project/pull/111616