1 //: Ingredients of a recipe are meant to be immutable unless they're also
  2 //: products. This layer will start enforcing this check.
  3 //:
  4 //: One hole for now: variables in surrounding spaces are implicitly mutable.
  5 //: [tag: todo]
  6 
  7 :(scenario can_modify_ingredients_that_are_also_products)
  8 # mutable container
  9 def main [
 10   local-scope
 11   p:point <- merge 34, 35
 12   p <- foo p
 13 ]
 14 def foo p:point -> p:point [
 15   local-scope
 16   load-ingredients
 17   p <- put p, x:offset, 34
 18 ]
 19 $error: 0
 20 
 21 :(scenario can_modify_ingredients_that_are_also_products_2)
 22 def main [
 23   local-scope
 24   p:&:point <- new point:type
 25   p <- foo p
 26 ]
 27 # mutable address to container
 28 def foo p:&:point -> p:&:point [
 29   local-scope
 30   load-ingredients
 31   *p <- put *p, x:offset, 34
 32 ]
 33 $error: 0
 34 
 35 :(scenario can_modify_ingredients_that_are_also_products_3)
 36 def main [
 37   local-scope
 38   p:&:@:num <- new number:type, 3
 39   p <- foo p
 40 ]
 41 # mutable address
 42 def foo p:&:@:num -> p:&:@:num [
 43   local-scope
 44   load-ingredients
 45   *p <- put-index *p, 0, 34
 46 ]
 47 $error: 0
 48 
 49 :(scenario ignore_literal_ingredients_for_immutability_checks)
 50 def main [
 51   local-scope
 52   p:&:d1 <- new d1:type
 53   q:num <- foo p
 54 ]
 55 def foo p:&:d1 -> q:num [
 56   local-scope
 57   load-ingredients
 58   x:&:d1 <- new d1:type
 59   *x <- put *x, p:offset, 34  # ignore this 'p'
 60   return 36
 61 ]
 62 container d1 [
 63   p:num
 64   q:num
 65 ]
 66 $error: 0
 67 
 68 :(scenario cannot_modify_immutable_ingredients)
 69 % Hide_errors = true;
 70 def main [
 71   local-scope
 72   x:&:num <- new number:type
 73   foo x
 74 ]
 75 # immutable address to primitive
 76 def foo x:&:num [
 77   local-scope
 78   load-ingredients
 79   *x <- copy 34
 80 ]
 81 +error: foo: cannot modify 'x' in instruction '*x <- copy 34' because it's an ingredient of recipe foo but not also a product
 82 
 83 :(scenario cannot_modify_immutable_containers)
 84 % Hide_errors = true;
 85 def main [
 86   local-scope
 87   x:point-number <- merge 34, 35, 36
 88   foo x
 89 ]
 90 # immutable container
 91 def foo x:point-number [
 92   local-scope
 93   load-ingredients
 94   # copy an element: ok
 95   y:point <- get x, xy:offset
 96   # modify the element: boom
 97   # This could be ok if y contains no addresses, but we're not going to try to be that smart.
 98   # It also makes the rules easier to reason about. If it's just an ingredient, just don't try to change it.
 99   y <- put y, x:offset, 37
100 ]
101 +error: foo: cannot modify 'y' in instruction 'y <- put y, x:offset, 37' because that would modify 'x' which is an ingredient of recipe foo but not also a product
102 
103 :(scenario can_modify_immutable_pointers)
104 def main [
105   local-scope
106   x:&:num <- new number:type
107   foo x
108 ]
109 def foo x:&:num [
110   local-scope
111   load-ingredients
112   # modify the address, not the payload
113   x <- copy null
114 ]
115 $error: 0
116 
117 :(scenario can_modify_immutable_pointers_but_not_their_payloads)
118 % Hide_errors = true;
119 def main [
120   local-scope
121   x:&:num <- new number:type
122   foo x
123 ]
124 def foo x:&:num [
125   local-scope
126   load-ingredients
127   # modify address; ok
128   x <- new number:type
129   # modify payload: boom
130   # this could be ok, but we're not going to try to be that smart
131   *x <- copy 34
132 ]
133 +error: foo: cannot modify 'x' in instruction '*x <- copy 34' because it's an ingredient of recipe foo but not also a product
134 
135 :(scenario cannot_call_mutating_recipes_on_immutable_ingredients)
136 % Hide_errors = true;
137 def main [
138   local-scope
139   p:&:point <- new point:type
140   foo p
141 ]
142 def foo p:&:point [
143   local-scope
144   load-ingredients
145   bar p
146 ]
147 def bar p:&:point -> p:&:point [
148   local-scope
149   load-ingredients
150   # p could be modified here, but it doesn't have to be, it's already marked
151   # mutable in the header
152 ]
153 +error: foo: cannot modify 'p' in instruction 'bar p' because it's an ingredient of recipe foo but not also a product
154 
155 :(scenario cannot_modify_copies_of_immutable_ingredients)
156 % Hide_errors = true;
157 def main [
158   local-scope
159   p:&:point <- new point:type
160   foo p
161 ]
162 def foo p:&:point [
163   local-scope
164   load-ingredients
165   q:&:point <- copy p
166   *q <- put *q, x:offset, 34
167 ]
168 +error: foo: cannot modify 'q' in instruction '*q <- put *q, x:offset, 34' because that would modify p which is an ingredient of recipe foo but not also a product
169 
170 :(scenario can_modify_copies_of_mutable_ingredients)
171 def main [
172   local-scope
173   p:&:point <- new point:type
174   foo p
175 ]
176 def foo p:&:point -> p:&:point [
177   local-scope
178   load-ingredients
179   q:&:point <- copy p
180   *q <- put *q, x:offset, 34
181 ]
182 $error: 0
183 
184 :(scenario cannot_modify_address_inside_immutable_ingredients)
185 % Hide_errors = true;
186 container foo [
187   x:&:@:num  # contains an address
188 ]
189 def main [
190   # don't run anything
191 ]
192 def foo a:&:foo [
193   local-scope
194   load-ingredients
195   x:&:@:num <- get *a, x:offset  # just a regular get of the container
196   *x <- put-index *x, 0, 34  # but then a put-index on the result
197 ]
198 +error: foo: cannot modify 'x' in instruction '*x <- put-index *x, 0, 34' because that would modify a which is an ingredient of recipe foo but not also a product
199 
200 :(scenario cannot_modify_address_inside_immutable_ingredients_2)
201 container foo [
202   x:&:@:num  # contains an address
203 ]
204 def main [
205   # don't run anything
206 ]
207 def foo a:&:foo [
208   local-scope
209   load-ingredients
210   b:foo <- merge null
211   # modify b, completely unrelated to immutable ingredient a
212   x:&:@:num <- get b, x:offset
213   *x <- put-index *x, 0, 34
214 ]
215 $error: 0
216 
217 :(scenario cannot_modify_address_inside_immutable_ingredients_3)
218 % Hide_errors = true;
219 def main [
220   # don't run anything
221 ]
222 def foo a:&:@:&:num [
223   local-scope
224   load-ingredients
225   x:&:num <- index *a, 0  # just a regular index of the array
226   *x <- copy 34  # but then modify the result
227 ]
228 +error: foo: cannot modify 'x' in instruction '*x <- copy 34' because that would modify a which is an ingredient of recipe foo but not also a product
229 
230 :(scenario cannot_modify_address_inside_immutable_ingredients_4)
231 def main [
232   # don't run anything
233 ]
234 def foo a:&:@:&:num [
235   local-scope
236   load-ingredients
237   b:&:@:&:num <- new {(address number): type}, 3
238   # modify b, completely unrelated to immutable ingredient a
239   x:&:num <- index *b, 0
240   *x <- copy 34
241 ]
242 $error: 0
243 
244 :(scenario latter_ingredient_of_index_is_immutable)
245 def main [
246   # don't run anything
247 ]
248 def foo a:&:@:&:@:num, b:num -> a:&:@:&:@:num [
249 <