rename `NativeString` to `CString`

[nit.git] / src / semantize / typing.nit

diff --git a/src/semantize/typing.nit b/src/semantize/typing.nit
index 6c4de01..d586881 100644 (file)
--- a/src/semantize/typing.nit
+++ b/src/semantize/typing.nit
@@ -102,9 +102,9 @@ private class TypeVisitor
        end
 
        # Check that `sub` is a subtype of `sup`.
-       # If `sub` is not a valid suptype, then display an error on `node` an return null.
-       # If `sub` is a safe subtype of `sup` then return `sub`.
-       # If `sub` is an unsafe subtype (ie an implicit cast is required), then return `sup`.
+       # If `sub` is not a valid suptype, then display an error on `node` and return `null`.
+       # If `sub` is a safe subtype of `sup`, then return `sub`.
+       # If `sub` is an unsafe subtype (i.e., an implicit cast is required), then return `sup`.
        #
        # The point of the return type is to determinate the usable type on an expression when `autocast` is true:
        # If the suptype is safe, then the return type is the one on the expression typed by `sub`.
@@ -117,7 +117,7 @@ private class TypeVisitor
                        #node.debug("Unsafe typing: expected {sup}, got {sub}")
                        return sup
                end
-               if sup isa MBottomType then return null # Skip error
+               if sup isa MErrorType then return null # Skip error
                if sub.need_anchor then
                        var u = anchor_to(sub)
                        self.modelbuilder.error(node, "Type Error: expected `{sup}`, got `{sub}: {u}`.")
@@ -1480,7 +1480,7 @@ redef class AugmentedStringFormExpr
        var newline: nullable CallSite = null
        # Regex::extended, used for suffix `b` on `re`
        var extended: nullable CallSite = null
-       # NativeString::to_bytes_with_copy, used for prefix `b`
+       # CString::to_bytes_with_copy, used for prefix `b`
        var to_bytes_with_copy: nullable CallSite = null
 
        redef fun accept_typing(v) do
@@ -1666,11 +1666,15 @@ redef class AIsaExpr
 
                var variable = self.n_expr.its_variable
                if variable != null then
-                       #var orig = self.n_expr.mtype
+                       var orig = self.n_expr.mtype
                        #var from = if orig != null then orig.to_s else "invalid"
                        #var to = if mtype != null then mtype.to_s else "invalid"
                        #debug("adapt {variable}: {from} -> {to}")
-                       self.after_flow_context.when_true.set_var(v, variable, mtype)
+
+                       # Do not adapt if there is no information gain (i.e. adapt to a supertype)
+                       if mtype == null or orig == null or not v.is_subtype(orig, mtype) then
+                               self.after_flow_context.when_true.set_var(v, variable, mtype)
+                       end
                end
 
                self.mtype = v.type_bool(self)