[clang-tools-extra] 392bd57 - [clangd] Guard against trivial FunctionProtoTypeLoc when creating inlay hints (#143087)

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Author: Nathan Ridge
Date: 2025-06-09T00:33:20-04:00
New Revision: 392bd577e37d795224da6fefc4b621a3f117105e

URL: https://github.com/llvm/llvm-project/commit/392bd577e37d795224da6fefc4b621a3f117105e
DIFF: https://github.com/llvm/llvm-project/commit/392bd577e37d795224da6fefc4b621a3f117105e.diff

LOG: [clangd] Guard against trivial FunctionProtoTypeLoc when creating inlay hints (#143087)

Fixes https://github.com/llvm/llvm-project/issues/142608

Added: 
    

Modified: 
    clang-tools-extra/clangd/InlayHints.cpp
    clang-tools-extra/clangd/unittests/InlayHintTests.cpp

Removed: 
    


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diff  --git a/clang-tools-extra/clangd/InlayHints.cpp b/clang-tools-extra/clangd/InlayHints.cpp
index bdab2b8a9f377..20a238612a7e4 100644
--- a/clang-tools-extra/clangd/InlayHints.cpp
+++ b/clang-tools-extra/clangd/InlayHints.cpp
@@ -33,6 +33,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
+#include "llvm/ADT/identity.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FormatVariadic.h"
@@ -375,7 +376,11 @@ static FunctionProtoTypeLoc getPrototypeLoc(Expr *Fn) {
   }
 
   if (auto F = Target.getAs<FunctionProtoTypeLoc>()) {
-    return F;
+    // In some edge cases the AST can contain a "trivial" FunctionProtoTypeLoc
+    // which has null parameters. Avoid these as they don't contain useful
+    // information.
+    if (llvm::all_of(F.getParams(), llvm::identity<ParmVarDecl *>()))
+      return F;
   }
 
   return {};

diff  --git a/clang-tools-extra/clangd/unittests/InlayHintTests.cpp b/clang-tools-extra/clangd/unittests/InlayHintTests.cpp
index c3331d20730f1..e0cd955bb1c9a 100644
--- a/clang-tools-extra/clangd/unittests/InlayHintTests.cpp
+++ b/clang-tools-extra/clangd/unittests/InlayHintTests.cpp
@@ -1011,11 +1011,16 @@ TEST(ParameterHints, FunctionPointer) {
     f3_t f3;
     using f4_t = void(__stdcall *)(int param);
     f4_t f4;
+    __attribute__((noreturn)) f4_t f5;
     void bar() {
       f1($f1[[42]]);
       f2($f2[[42]]);
       f3($f3[[42]]);
       f4($f4[[42]]);
+      // This one runs into an edge case in clang's type model
+      // and we can't extract the parameter name. But at least
+      // we shouldn't crash.
+      f5(42);
     }
   )cpp",
       ExpectedHint{"param: ", "f1"}, ExpectedHint{"param: ", "f2"},