[PATCH] D38700: [Sema][Crash] Correctly handle an non-dependent noexcept expr in function template

[Erich Keane via Phabricator via cfe-commits]

erichkeane created this revision.

It seems that all of the other templated cases are handled correctly,
however the function template case was not correctly handled.  This
patch recovers from this condition by setting the function to noexcept
after diagnosing.  Previously it simply set NoexceptExpr to null,
which caused an Assert when this was evaluated during substitution.


https://reviews.llvm.org/D38700

Files:
  lib/Sema/SemaDeclCXX.cpp
  test/CXX/except/except.spec/p1.cpp


Index: test/CXX/except/except.spec/p1.cpp
===================================================================
--- test/CXX/except/except.spec/p1.cpp
+++ test/CXX/except/except.spec/p1.cpp
@@ -86,3 +86,12 @@
     f<0>(); // expected-note{{in instantiation of function template 
specialization}}
   }
 }
+
+namespace FuncTmplNoexceptError {
+  int a = 0;
+  // expected-error@+1{{argument to noexcept specifier must be a constant 
expression}}
+  template <class T> T f() noexcept(a++){ return {};}
+  void g(){
+    f<int>();
+  }
+};
Index: lib/Sema/SemaDeclCXX.cpp
===================================================================
--- lib/Sema/SemaDeclCXX.cpp
+++ lib/Sema/SemaDeclCXX.cpp
@@ -14858,10 +14858,16 @@
         return;
       }
 
-      if (!NoexceptExpr->isValueDependent())
-        NoexceptExpr = VerifyIntegerConstantExpression(NoexceptExpr, nullptr,
-                         diag::err_noexcept_needs_constant_expression,
-                         /*AllowFold*/ false).get();
+      if (!NoexceptExpr->isValueDependent()) {
+        ExprResult Result = VerifyIntegerConstantExpression(
+            NoexceptExpr, nullptr, 
diag::err_noexcept_needs_constant_expression,
+            /*AllowFold*/ false);
+        if (Result.isInvalid()) {
+          ESI.Type = EST_BasicNoexcept;
+          return;
+        }
+        NoexceptExpr = Result.get();
+      }
       ESI.NoexceptExpr = NoexceptExpr;
     }
     return;



Index: test/CXX/except/except.spec/p1.cpp
===================================================================
--- test/CXX/except/except.spec/p1.cpp
+++ test/CXX/except/except.spec/p1.cpp
@@ -86,3 +86,12 @@
     f<0>(); // expected-note{{in instantiation of function template specialization}}
   }
 }
+
+namespace FuncTmplNoexceptError {
+  int a = 0;
+  // expected-error@+1{{argument to noexcept specifier must be a constant expression}}
+  template <class T> T f() noexcept(a++){ return {};}
+  void g(){
+    f<int>();
+  }
+};
Index: lib/Sema/SemaDeclCXX.cpp
===================================================================
--- lib/Sema/SemaDeclCXX.cpp
+++ lib/Sema/SemaDeclCXX.cpp
@@ -14858,10 +14858,16 @@
         return;
       }
 
-      if (!NoexceptExpr->isValueDependent())
-        NoexceptExpr = VerifyIntegerConstantExpression(NoexceptExpr, nullptr,
-                         diag::err_noexcept_needs_constant_expression,
-                         /*AllowFold*/ false).get();
+      if (!NoexceptExpr->isValueDependent()) {
+        ExprResult Result = VerifyIntegerConstantExpression(
+            NoexceptExpr, nullptr, diag::err_noexcept_needs_constant_expression,
+            /*AllowFold*/ false);
+        if (Result.isInvalid()) {
+          ESI.Type = EST_BasicNoexcept;
+          return;
+        }
+        NoexceptExpr = Result.get();
+      }
       ESI.NoexceptExpr = NoexceptExpr;
     }
     return;

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