3752 - fix a couple of segfaults

Thanks Ella Couch for running into these.

021check_instruction.cc

@@ -126,6 +126,7 @@ bool types_match(const reagent& to, const reagent& from) {
 //: copy arguments for later layers
 bool types_strictly_match(reagent/*copy*/ to, reagent/*copy*/ from) {
   // End Preprocess types_strictly_match(reagent to, reagent from)
+  if (to.type == NULL) return false;  // error
   if (is_literal(from) && to.type->value == get(Type_ordinal, "number")) return true;
   // to sidestep type-checking, use /unsafe in the source.
   // this will be highlighted in red inside vim. just for setting up some tests.

053recipe_header.cc

@@ -365,12 +365,29 @@ def foo -> x:num [
 
 :(scenario recipe_headers_check_for_duplicate_names)
 % Hide_errors = true;
-def add2 x:num, x:num -> z:num [
+def foo x:num, x:num -> z:num [
   local-scope
   load-ingredients
   return z
 ]
-+error: add2: 'x' can't repeat in the ingredients
++error: foo: 'x' can't repeat in the ingredients
+
+:(scenario recipe_headers_check_for_duplicate_names_2)
+% Hide_errors = true;
+def foo x:num, x:num [  # no result
+  local-scope
+  load-ingredients
+]
++error: foo: 'x' can't repeat in the ingredients
+
+:(scenario recipe_headers_check_for_missing_types)
+% Hide_errors = true;
+def main [
+  foo 0
+]
+def foo a [  # no type for 'a'
+]
++error: foo: ingredient 'a' has no type
 
 :(before "End recipe Fields")
 map<string, int> ingredient_index;
@@ -381,10 +398,11 @@ Transform.push_back(check_header_ingredients);  // idempotent
 :(code)
 void check_header_ingredients(const recipe_ordinal r) {
   recipe& caller_recipe = get(Recipe, r);
-  if (caller_recipe.products.empty()) return;
   caller_recipe.ingredient_index.clear();
   trace(9991, "transform") << "--- checking return instructions against header for " << caller_recipe.name << end();
   for (int i = 0;  i < SIZE(caller_recipe.ingredients);  ++i) {
+    if (caller_recipe.ingredients.at(i).type == NULL)
+      raise << maybe(caller_recipe.name) << "ingredient '" << caller_recipe.ingredients.at(i).name << "' has no type\n" << end();
     if (contains_key(caller_recipe.ingredient_index, caller_recipe.ingredients.at(i).name))
       raise << maybe(caller_recipe.name) << "'" << caller_recipe.ingredients.at(i).name << "' can't repeat in the ingredients\n" << end();
     put(caller_recipe.ingredient_index, caller_recipe.ingredients.at(i).name, i);