Fixing an ICE with dependent contract conditions

Author: NinaRanns

gcc/cp/pt.cc

@@ -12060,7 +12060,15 @@ tsubst_contract (tree decl, tree t, tree args, tsubst_flags_t complain,
   CONTRACT_CONDITION (r)
       = tsubst_expr (CONTRACT_CONDITION (t), args, complain, in_decl);
 
+  /* The condition is converted to bool.  */
+  CONTRACT_CONDITION (r) = finish_contract_condition (CONTRACT_CONDITION (r));
+
   /* And the comment.  */
+  /* TODO : this does not do anything at the moment. The CONTRACT_COMMENT is
+     (currently) a string literal, built from the string of the contract.
+     There is nothing to substitute. If we wanted to rebuild the
+     CONTRACT_COMMENT from the substituted contract tree, we would need to
+     modify how a CONTRACT_COMMENT is built.  */
   CONTRACT_COMMENT (r)
       = tsubst_expr (CONTRACT_COMMENT (r), args, complain, in_decl);
 

gcc/testsuite/g++.dg/contracts/cpp26/dependent_contract.C

@@ -0,0 +1,32 @@
+// check that dependent contract check does not cause an ICE
+// { dg-do run }
+// { dg-options "-std=c++2a -fcontracts -fcontracts-nonattr -fcontract-evaluation-semantic=observe " }
+template <typename ST>
+struct S{
+
+  int* check() const
+  {
+      static int i = 6;
+      return &i;
+  }
+
+  template <typename T>
+  T* tcheck(T) const{
+    static T t;
+    return nullptr;
+  }
+
+  void f() pre(check()) pre(tcheck(1)){
+  }
+
+  template <typename T>
+  void f(T t) pre(check()) pre(tcheck(1)) pre(tcheck<T>(t)){
+  }
+
+};
+
+int main() {
+    S<int> s;
+    s.f();
+    s.f(1);
+}