[clang-doc] Fix assertions error in Serialize.cpp

[ilovepi]

We can only print and use a default arg, if it is instantiated.
I was unable to reduce the test case for this to something of reasonable
size, but this is easily hit by running clang-doc to generate clang's
documentation. For now, we can fix the assertion quickly to unbreak
users, and add the proper test once it is small enough.

[ilovepi]

• [clang-doc] Fix assertions error in Serialize.cpp #141990 👈 (View in Graphite)
• main

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[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[llvmbot]

@llvm/pr-subscribers-clang-tools-extra

Author: Paul Kirth (ilovepi)

Changes

We can only print and use a default arg, if it is instantiated.
I was unable to reduce the test case for this to something of reasonable
size, but this is easily hit by running clang-doc to generate clang's
documentation. For now, we can fix the assertion quickly to unbreak
users, and add the proper test once it is small enough.

---

Full diff: https://github.com/llvm/llvm-project/pull/141990.diff

1 Files Affected:

• (modified) clang-tools-extra/clang-doc/Serialize.cpp (+3-3)

diff --git a/clang-tools-extra/clang-doc/Serialize.cpp b/clang-tools-extra/clang-doc/Serialize.cpp
index 97ea1f02a6178..3932a939de973 100644
--- a/clang-tools-extra/clang-doc/Serialize.cpp
+++ b/clang-tools-extra/clang-doc/Serialize.cpp
@@ -113,9 +113,9 @@ getFunctionPrototype(const FunctionDecl *FuncDecl) {
       Stream << " " << ParamDecl->getNameAsString();
 
     // Print default argument if it exists
-    if (ParamDecl->hasDefaultArg()) {
-      const Expr *DefaultArg = ParamDecl->getDefaultArg();
-      if (DefaultArg) {
+    if (ParamDecl->hasDefaultArg() &&
+        !ParamDecl->hasUninstantiatedDefaultArg()) {
+      if (const Expr *DefaultArg = ParamDecl->getDefaultArg()) {
         Stream << " = ";
         DefaultArg->printPretty(Stream, nullptr, Ctx.getPrintingPolicy());
       }

[evelez7]

LGTM.