function/stdlib: Don't panic if one of the setproduct arguments is an…

… empty collection

Due to some incorrect marking in the empty result codepaths, this was causing panics.
When applying a ValueMarks we must use WithMarks, not Mark.

cty/function/stdlib/collection.go

@@ -953,9 +953,9 @@ var SetProductFunc = function.New(&function.Spec{
 			// If any of the arguments was an empty collection then our result
 			// is also an empty collection, which we'll short-circuit here.
 			if retType.IsListType() {
-				return cty.ListValEmpty(ety).Mark(retMarks), nil
+				return cty.ListValEmpty(ety).WithMarks(retMarks), nil
 			}
-			return cty.SetValEmpty(ety).Mark(retMarks), nil
+			return cty.SetValEmpty(ety).WithMarks(retMarks), nil
 		}
 
 		subEtys := ety.TupleElementTypes()

cty/function/stdlib/collection_test.go

@@ -1939,6 +1939,44 @@ func TestSetproduct(t *testing.T) {
 			cty.NilVal,
 			`at least two arguments are required`,
 		},
+		{
+			[]cty.Value{
+				cty.ListValEmpty(cty.EmptyObject),
+				cty.ListVal([]cty.Value{
+					cty.StringVal("quick"),
+					cty.StringVal("fox"),
+				}),
+			},
+			cty.ListValEmpty(cty.Tuple([]cty.Type{cty.EmptyObject, cty.String})),
+			``,
+		},
+		{
+			[]cty.Value{
+				cty.SetValEmpty(cty.EmptyObject),
+				cty.SetVal([]cty.Value{
+					cty.StringVal("quick"),
+					cty.StringVal("fox"),
+				}),
+			},
+			cty.SetValEmpty(cty.Tuple([]cty.Type{cty.EmptyObject, cty.String})),
+			``,
+		},
+		{
+			[]cty.Value{
+				cty.ListValEmpty(cty.EmptyObject),
+				cty.ListValEmpty(cty.EmptyObject),
+			},
+			cty.ListValEmpty(cty.Tuple([]cty.Type{cty.EmptyObject, cty.EmptyObject})),
+			``,
+		},
+		{
+			[]cty.Value{
+				cty.SetValEmpty(cty.EmptyObject),
+				cty.SetValEmpty(cty.EmptyObject),
+			},
+			cty.SetValEmpty(cty.Tuple([]cty.Type{cty.EmptyObject, cty.EmptyObject})),
+			``,
+		},
 		{
 			[]cty.Value{
 				cty.ListVal([]cty.Value{cty.ListValEmpty(cty.String)}),