abstract_compiler: Add import contract

[nit.git] / src / compiler / abstract_compiler.nit

diff --git a/src/compiler/abstract_compiler.nit b/src/compiler/abstract_compiler.nit
index 1f26f6e..e10be39 100644 (file)
--- a/src/compiler/abstract_compiler.nit
+++ b/src/compiler/abstract_compiler.nit
@@ -26,6 +26,7 @@ import mixin
 import counter
 import pkgconfig
 private import explain_assert_api
+import contracts
 
 # Add compiling options
 redef class ToolContext
@@ -4392,9 +4393,25 @@ redef class ASendExpr
                var res = v.compile_callsite(callsite, args)
                if is_safe then
                        if res != null then
-                               var orig_res = res
+                               # `callsite.mpropdef` may reference a method whose
+                               # return type is a primitive type in C. If it is
+                               # the case, we must convert the primitive type to
+                               # a `val*` to support nullable assignment.
+                               # Autobox's job is to convert primitive type to
+                               # nullable type, eg from `Int` to `nullable `Int`.
+                               # The target type reside in `self.mtype`.
+                               var original_res = v.autobox(res, self.mtype.as(not null))
+
+                               # Here we must create a new_var in case the original
+                               # type is not nullable. We can't call `autobox` to
+                               # convert a complex type to its nullable version.
+                               # eg if we have a type `A`, calling autobox like
+                               # `autobox(A, nullable A)` will return `A` since
+                               # `A` and `nullable A` have the same primitive
+                               # type. The nullable qualifier is only used at
+                               # compile time to add appropriate null checks.
                                res = v.new_var(self.mtype.as(not null))
-                               v.add("{res} = {orig_res};")
+                               v.add("{res} = {original_res};")
                                v.add("\} else \{")
                                v.add("{res} = NULL;")
                        end