[clang][ExprConstant] Bail out on invalid lambda capture inits (#138832)

Fixes #138824

Author: tbaederr

clang/docs/ReleaseNotes.rst

@@ -564,6 +564,8 @@ Bug Fixes in This Version
   the invalid attribute location appropriately. (#GH137861)
 - Fixed a crash when a malformed ``_Pragma`` directive appears as part of an 
   ``#include`` directive. (#GH138094)
+- Fixed a crash during constant evaluation involving invalid lambda captures
+  (#GH138832)
 
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

clang/lib/AST/ByteCode/Compiler.cpp

@@ -2932,10 +2932,9 @@ bool Compiler<Emitter>::VisitLambdaExpr(const LambdaExpr *E) {
   // record with their initializers.
   for (const Record::Field &F : R->fields()) {
     const Expr *Init = *CaptureInitIt;
-    ++CaptureInitIt;
-
-    if (!Init)
+    if (!Init || Init->containsErrors())
       continue;
+    ++CaptureInitIt;
 
     if (std::optional<PrimType> T = classify(Init)) {
       if (!this->visit(Init))

clang/lib/AST/ExprConstant.cpp

@@ -11038,7 +11038,7 @@ bool RecordExprEvaluator::VisitLambdaExpr(const LambdaExpr *E) {
 
     // If there is no initializer, either this is a VLA or an error has
     // occurred.
-    if (!CurFieldInit)
+    if (!CurFieldInit || CurFieldInit->containsErrors())
       return Error(E);
 
     LValue Subobject = This;

clang/test/SemaCXX/constant-expression-cxx11.cpp

@@ -2598,3 +2598,12 @@ void foo() {
   constexpr S s[2] = { }; // expected-error {{constexpr variable 's' must be initialized by a constant expression}}
 }
 }
+
+namespace DoubleCapture {
+  int DC() {
+  int a = 1000;
+    static auto f =
+      [a, &a] { // expected-error {{'a' can appear only once in a capture list}}
+    };
+  }
+}