[AST] Stop evaluate constant expression if the condition expression which in switch statement contains errors

This fix issue: #63453 ``` constexpr int foo(unsigned char c) { switch (f) { case 0: return 7; default: break; } return 0; } static_assert(foo('d')); ``` Reviewed By: aaron.ballman, erichkeane, hokein Differential Revision: https://reviews.llvm.org/D153296

Author: yronglin

clang/docs/ReleaseNotes.rst

@@ -570,6 +570,9 @@ Bug Fixes in This Version
 - Clang now correctly evaluates ``__has_extension (cxx_defaulted_functions)``
  and ``__has_extension (cxx_default_function_template_args)`` to 1.
  (`#61758 <https://github.com/llvm/llvm-project/issues/61758>`_)
+- Stop evaluating a constant expression if the condition expression which in
+ switch statement contains errors.
+ (`#63453 <https://github.com/llvm/llvm-project/issues/63453>_`)
 
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

clang/lib/AST/ExprConstant.cpp

@@ -5007,12 +5007,13 @@ static EvalStmtResult EvaluateSwitch(StmtResult &Result, EvalInfo &Info,
  !EvaluateDecl(Info, SS->getConditionVariable()))
  return ESR_Failed;
  if (SS->getCond()->isValueDependent()) {
- if (!EvaluateDependentExpr(SS->getCond(), Info))
- return ESR_Failed;
- } else {
- if (!EvaluateInteger(SS->getCond(), Value, Info))
- return ESR_Failed;
+ // We don't know what the value is, and which branch should jump to.
+ EvaluateDependentExpr(SS->getCond(), Info);
+ return ESR_Failed;
  }
+ if (!EvaluateInteger(SS->getCond(), Value, Info))
+ return ESR_Failed;
+
  if (!CondScope.destroy())
  return ESR_Failed;
  }

clang/test/SemaCXX/constexpr-function-recovery-crash.cpp

@@ -87,6 +87,7 @@ constexpr int force12 = test12(); // expected-error {{must be initializ
 // We're not checking specific recovery here so don't assert diagnostics.
 TEST_EVALUATE(Switch, switch (!!){}); // expected-error + {{}}
 TEST_EVALUATE(SwitchInit, switch (auto x = !!){}); // expected-error + {{}}
+TEST_EVALUATE(SwitchCondValDep, switch (invalid_value) { default: break; }); // expected-error + {{}}
 TEST_EVALUATE(For, for (!!){}); // expected-error + {{}}
  // FIXME: should bail out instead of looping.
  // expected-note@-2 + {{infinite loop}}