This was an assert that was too picky. The reason I had to alter array construction was that on stream in, we cannot dynamically determine a type's dependentness. Thus on stream out of the 'problematic' types, we save the dependentness for reconstruction. Fortunately the paths into cp_build_qualified_type_real from streamin with arrays do have the array's dependentess set as needed.
PR c++/98538 gcc/cp/ * tree.c (cp_build_qualified_type_real): Propagate an array's dependentness to the copy, if known. gcc/testsuite/ g++.dg/template/pr98538.C: New. -- Nathan Sidwell
diff --git c/gcc/cp/tree.c w/gcc/cp/tree.c index 3a9a86de34a..55325d7c671 100644 --- c/gcc/cp/tree.c +++ w/gcc/cp/tree.c @@ -1332,10 +1332,12 @@ cp_build_qualified_type_real (tree type, if (!t) { - gcc_checking_assert (TYPE_DEPENDENT_P_VALID (type) - || !dependent_type_p (type)); + /* If we already know the dependentness, tell the array type + constructor. This is important for module streaming, as we cannot + dynamically determine that on read in. */ t = build_cplus_array_type (element_type, TYPE_DOMAIN (type), - TYPE_DEPENDENT_P (type)); + TYPE_DEPENDENT_P_VALID (type) + ? int (TYPE_DEPENDENT_P (type)) : -1); /* Keep the typedef name. */ if (TYPE_NAME (t) != TYPE_NAME (type)) diff --git c/gcc/testsuite/g++.dg/template/pr98538.C w/gcc/testsuite/g++.dg/template/pr98538.C new file mode 100644 index 00000000000..b62e8a96af8 --- /dev/null +++ w/gcc/testsuite/g++.dg/template/pr98538.C @@ -0,0 +1,18 @@ +// PR c++/98538 +// { dg-do compile { target c++11 } } +// ICE bulding a dependent array type variant + +template<typename T> using A = int[1]; +template<typename T, const A<T>> struct X { }; + +template<typename T> +void +f (const A<T>) +{ + const A<T> a; +} + +template<typename T> +struct Y { + const A<T> a; +};