[clang] [clang][ObjC][CodeComplete] Fix crash on C-Style cast with parenthesi… (PR #180343)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: None (edisongz)

<details>
<summary>Changes</summary>

…zed operand in ObjC++

In ObjC++ mode, code-completion after a C-style cast like `(int*)(0x200)` crashed because the inner parenthesized expression was parsed as a `ParenListExpr` (null type) due to `AllowTypes` propagation.

Add a null-type guard in CodeCompletePostfixExpression.

---
Full diff: https://github.com/llvm/llvm-project/pull/180343.diff


2 Files Affected:

- (modified) clang/lib/Sema/SemaCodeComplete.cpp (+1-1) 
- (added) clang/test/CodeCompletion/objc-cast-parenthesized-expr.m (+12) 


``````````diff
diff --git a/clang/lib/Sema/SemaCodeComplete.cpp b/clang/lib/Sema/SemaCodeComplete.cpp
index aa93507ab5c30..0d8ed56a1ede3 100644
--- a/clang/lib/Sema/SemaCodeComplete.cpp
+++ b/clang/lib/Sema/SemaCodeComplete.cpp
@@ -5152,7 +5152,7 @@ void SemaCodeCompletion::CodeCompletePostfixExpression(Scope *S, ExprResult E,
                                                        QualType PreferredType) {
   if (E.isInvalid())
     CodeCompleteExpression(S, PreferredType);
-  else if (getLangOpts().ObjC)
+  else if (getLangOpts().ObjC && !E.get()->getType().isNull())
     CodeCompleteObjCInstanceMessage(S, E.get(), {}, false);
 }
 
diff --git a/clang/test/CodeCompletion/objc-cast-parenthesized-expr.m b/clang/test/CodeCompletion/objc-cast-parenthesized-expr.m
new file mode 100644
index 0000000000000..171d62cf971f5
--- /dev/null
+++ b/clang/test/CodeCompletion/objc-cast-parenthesized-expr.m
@@ -0,0 +1,12 @@
+// Note: the run lines follow their respective tests, since line/column
+// matter in this test.
+
+void func() {
+  int *foo = (int *)(0x200);
+  int *bar = (int *)((0x200));
+}
+
+// Make sure this doesn't crash
+// RUN: %clang_cc1 -fsyntax-only -xobjective-c++-header -code-completion-at=%s:%(line-5):28 %s
+// RUN: %clang_cc1 -fsyntax-only -xobjective-c++-header -code-completion-at=%s:%(line-5):30 %s
+

``````````

</details>


https://github.com/llvm/llvm-project/pull/180343