PR c++/90548 - ICE with generic lambda and empty pack.

	* pt.c (tsubst_copy_and_build): Handle pack expansion properly.

	* g++.dg/cpp1y/lambda-generic-90548.C: New test.

From-SVN: r271708

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 40c920280dc20c3e42067e5d7571fb85c3102762..a0235a7dcbbeefbd0e3b290c3777c49d543faeef 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,11 @@
+2019-05-28  Marek Polacek  <polacek@redhat.com>
+
+       Backported from mainline
+       2019-05-28  Marek Polacek  <polacek@redhat.com>
+
+       PR c++/90548 - ICE with generic lambda and empty pack.
+       * pt.c (tsubst_copy_and_build): Handle pack expansion properly.
+
 2019-05-25  Marek Polacek  <polacek@redhat.com>
 
        Backported from mainline

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index f316644d430174cda052118ca68865beae48508b..9b5e6576b7e14fb02d2e868b8d41305e8234830e 100644 (file)
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -18856,6 +18856,9 @@ tsubst_copy_and_build (tree t,
           the thunk template for a generic lambda.  */
        if (CALL_FROM_THUNK_P (t))
          {
+           /* Now that we've expanded any packs, the number of call args
+              might be different.  */
+           unsigned int cargs = call_args->length ();
            tree thisarg = NULL_TREE;
            if (TREE_CODE (function) == COMPONENT_REF)
              {
@@ -18869,7 +18872,7 @@ tsubst_copy_and_build (tree t,
            /* We aren't going to do normal overload resolution, so force the
               template-id to resolve.  */
            function = resolve_nondeduced_context (function, complain);
-           for (unsigned i = 0; i < nargs; ++i)
+           for (unsigned i = 0; i < cargs; ++i)
              {
                /* In a thunk, pass through args directly, without any
                   conversions.  */
@@ -18880,12 +18883,18 @@ tsubst_copy_and_build (tree t,
              }
            if (thisarg)
              {
-               /* Shift the other args over to make room.  */
-               tree last = (*call_args)[nargs - 1];
-               vec_safe_push (call_args, last);
-               for (int i = nargs-1; i > 0; --i)
-                 (*call_args)[i] = (*call_args)[i-1];
-               (*call_args)[0] = thisarg;
+               /* If there are no other args, just push 'this'.  */
+               if (cargs == 0)
+                 vec_safe_push (call_args, thisarg);
+               else
+                 {
+                   /* Otherwise, shift the other args over to make room.  */
+                   tree last = (*call_args)[cargs - 1];
+                   vec_safe_push (call_args, last);
+                   for (int i = cargs - 1; i > 0; --i)
+                     (*call_args)[i] = (*call_args)[i - 1];
+                   (*call_args)[0] = thisarg;
+                 }
              }
            ret = build_call_a (function, call_args->length (),
                                call_args->address ());

diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-generic-90548.C b/gcc/testsuite/g++.dg/cpp1y/lambda-generic-90548.C
new file mode 100644 (file)
index 0000000..b845dd8
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/lambda-generic-90548.C
@@ -0,0 +1,22 @@
+// PR c++/90548
+// { dg-do compile { target c++14 } }
+
+struct S { S (void ()); };
+S foo([] (auto...) { });
+S foo2{[] (auto...) {}};
+S foo3 = {[] (auto...) {}};
+
+struct W { W(void (int)); };
+W bar([](auto...) { });
+W bar2{[](auto...) { }};
+W bar3 = {[](auto...) { }};
+
+struct T { T(void (int, int)); };
+T qux([](auto...) { });
+T qux2{[](auto...) { }};
+T qux3 = {[](auto...) { }};
+
+struct R { R(void (int, int, int, int, int, int, int, int, int, int)); };
+R baz([](auto...) { });
+R baz2{[](auto...) { }};
+R baz3 = {[](auto...) { }};