[gcc r15-1942] c++, contracts: Fix ICE in create_tmp_var [PR113968]

[Jason Merrill via Gcc-cvs]

https://gcc.gnu.org/g:c829042849da4e82668db8c845ef0847264c8687

commit r15-1942-gc829042849da4e82668db8c845ef0847264c8687
Author: Nina Ranns <dinka.ra...@gmail.com>
Date:   Thu Jul 4 17:08:58 2024 +0100

    c++, contracts: Fix ICE in create_tmp_var [PR113968]
    
    During contract parsing, in grok_contract(), we proceed even if the
    condition contains errors. This results in contracts with embedded errors
    which eventually confuse gimplify. Checks for errors have been added in
    grok_contract() to exit early if an error is encountered.
    
            PR c++/113968
    
    gcc/cp/ChangeLog:
    
            * contracts.cc (grok_contract): Check for error_mark_node early
            exit.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/contracts/pr113968.C: New test.
    
    Signed-off-by: Nina Ranns <dinka.ra...@gmail.com>

Diff:
---
 gcc/cp/contracts.cc                       |  7 +++++++
 gcc/testsuite/g++.dg/contracts/pr113968.C | 29 +++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/gcc/cp/contracts.cc b/gcc/cp/contracts.cc
index 634e3cf4fa9a..a7d0fdacf6ec 100644
--- a/gcc/cp/contracts.cc
+++ b/gcc/cp/contracts.cc
@@ -750,6 +750,9 @@ tree
 grok_contract (tree attribute, tree mode, tree result, cp_expr condition,
               location_t loc)
 {
+  if (condition == error_mark_node)
+    return error_mark_node;
+
   tree_code code;
   if (is_attribute_p ("assert", attribute))
     code = ASSERTION_STMT;
@@ -785,6 +788,10 @@ grok_contract (tree attribute, tree mode, tree result, 
cp_expr condition,
 
   /* The condition is converted to bool.  */
   condition = finish_contract_condition (condition);
+
+  if (condition == error_mark_node)
+    return error_mark_node;
+
   CONTRACT_CONDITION (contract) = condition;
 
   return contract;
diff --git a/gcc/testsuite/g++.dg/contracts/pr113968.C 
b/gcc/testsuite/g++.dg/contracts/pr113968.C
new file mode 100644
index 000000000000..fbaad1c930d5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/contracts/pr113968.C
@@ -0,0 +1,29 @@
+// check that an invalid contract condition doesn't cause an ICE
+// { dg-do compile }
+// { dg-options "-std=c++2a -fcontracts " }
+
+struct A
+{
+  A (A&);
+};
+struct S
+{
+  void f(A a)
+    [[ pre : a]] // { dg-error "could not convert" }
+    [[ pre : a.b]]// { dg-error "has no member" }
+    {
+
+    }
+};
+void f(A a)
+  [[ pre : a]] // { dg-error "could not convert" }
+  [[ pre : a.b]]// { dg-error "has no member" }
+  {
+    [[ assert : a ]]; // { dg-error "could not convert" }
+    [[ assert : a.b ]];// { dg-error "has no member" }
+  }
+
+int
+main ()
+{
+}