Remove Blank, support Erroneous

src/pretty_print_types.rs

@@ -70,6 +70,9 @@ fn write_flat_type(flat_type: FlatType, subs: &mut Subs, buf: &mut String, use_p
             if use_parens {
                 buf.push_str(")");
             }
+        },
+        Erroneous(problem) => {
+            buf.push_str(&format!("<Type Mismatch: {:?}>", problem));
         }
     }
 }

src/solve.rs

@@ -106,16 +106,11 @@ fn type_to_variable(subs: &mut Subs, typ: Type) -> Variable {
 
             subs.fresh(Descriptor::from(content))
         },
-        _ => panic!("TODO type_to_var {:?}", typ)
+        Erroneous(problem) => {
+            let content = Content::Structure(FlatType::Erroneous(problem));
 
-        // AppN home name args ->
+            subs.fresh(Descriptor::from(content))
-        // do  argVars <- traverse go args
+        }
-        //     register rank pools (Structure (App1 home name argVars))
-
-        // FunN a b ->
-        // do  aVar <- go a
-        //     bVar <- go b
-        //     register rank pools (Structure (Fun1 aVar bVar))
     }
 }
 

src/subs.rs

@@ -1,7 +1,9 @@
 use ena::unify::{UnificationTable, UnifyKey, InPlace};
 use std::fmt;
+use types::Problem;
 use unify;
 
+#[derive(Debug)]
 pub struct Subs {
     utable: UnificationTable<InPlace<Variable>>
 }
@@ -141,6 +143,7 @@ pub enum Content {
 pub enum FlatType {
     Apply(String /* module name */, String /* type name */, Vec<Variable>),
     Func(Vec<Variable>, Variable),
+    Erroneous(Problem),
     EmptyRecord,
 }
 

src/types.rs

@@ -15,8 +15,6 @@ pub enum Type {
     /// Applying a type to some arguments (e.g. Map.Map String Int)
     Apply(ModuleName, String, Vec<Type>),
     Variable(Variable),
-    /// A Blank in the editor (a "typed hole" as they're also known)
-    Blank,
     /// A type error, which will code gen to a runtime error
     Erroneous(Problem),
 }