subtype unification: check seq-/struct-/enum-repr type

src/morphism_path_sugared.rs

@@ -91,10 +91,10 @@ impl<'a, M:SugaredMorphism+Clone> SugaredShortestPathProblem<'a, M> {
                     self.morphism_base.complex_morphism_decomposition( &cur_path.cur_type, &self.goal )
                 {
                     self.advance(&cur_path, complex_morph);
-                } else {
-                    for next_morph_inst in self.morphism_base.enum_morphisms_from(&cur_path.cur_type) {
-                        self.advance(&cur_path, next_morph_inst);
-                    }
+                }
+
+                for next_morph_inst in self.morphism_base.enum_morphisms_from(&cur_path.cur_type) {
+                    self.advance(&cur_path, next_morph_inst);
                 }
             }
         }

src/unification_sugared.rs

@@ -329,9 +329,20 @@ impl SugaredUnificationProblem {
             (SugaredTypeTerm::Seq{ seq_repr: lhs_seq_repr, items: lhs_items },
                 SugaredTypeTerm::Seq { seq_repr: rhs_seq_repr, items: rhs_items })
             => {
+                let mut new_addr = unification_pair.addr.clone();
+                new_addr.push(0);
+
+                if let Some(rhs_seq_repr) = rhs_seq_repr.as_ref() {
+                    if let Some(lhs_seq_repr) = lhs_seq_repr.as_ref() {
+                        let _seq_repr_ψ = self.eval_subtype(SugaredUnificationPair { addr: new_addr.clone(), lhs: *lhs_seq_repr.clone(), rhs: *rhs_seq_repr.clone() })?;
+                    } else {
+                        return Err(SugaredUnificationError{ addr: new_addr, t1: unification_pair.lhs, t2: unification_pair.rhs });
+                    }
+                }
+
+                let mut new_addr = unification_pair.addr.clone();
+                new_addr.push(1);
                 if lhs_items.len() == rhs_items.len() && lhs_items.len() > 0 {
-                    let mut new_addr = unification_pair.addr.clone();
-                    new_addr.push(0);
                     match self.eval_subtype( SugaredUnificationPair { addr: new_addr.clone(), lhs: lhs_items[0].clone(), rhs: rhs_items[0].clone() } ) {
                         Ok(ψ) => Ok(SugaredTypeTerm::Seq {
                                 seq_repr: None, // <<- todo
@@ -344,12 +355,21 @@ impl SugaredUnificationProblem {
                             })
                     }
                 } else {
-                    Err(SugaredUnificationError{ addr: unification_pair.addr, t1: unification_pair.lhs, t2: unification_pair.rhs })
+                    Err(SugaredUnificationError{ addr: new_addr, t1: unification_pair.lhs, t2: unification_pair.rhs })
                 }
             }
             (SugaredTypeTerm::Struct{ struct_repr: lhs_struct_repr, members: lhs_members },
                 SugaredTypeTerm::Struct{ struct_repr: rhs_struct_repr, members: rhs_members })
             => {
+                let new_addr = unification_pair.addr.clone();
+                if let Some(rhs_struct_repr) = rhs_struct_repr.as_ref() {
+                    if let Some(lhs_struct_repr) = lhs_struct_repr.as_ref() {
+                        let _struct_repr_ψ = self.eval_subtype(SugaredUnificationPair { addr: new_addr.clone(), lhs: *lhs_struct_repr.clone(), rhs: *rhs_struct_repr.clone() })?;
+                    } else {
+                        return Err(SugaredUnificationError{ addr: new_addr.clone(), t1: unification_pair.lhs, t2: unification_pair.rhs });
+                    }
+                }
+
                 if lhs_members.len() == rhs_members.len() {
                     let mut halo_members = Vec::new();
                     for (i,
@@ -375,6 +395,15 @@ impl SugaredUnificationProblem {
             (SugaredTypeTerm::Enum{ enum_repr: lhs_enum_repr, variants: lhs_variants },
                 SugaredTypeTerm::Enum{ enum_repr: rhs_enum_repr, variants: rhs_variants })
             => {
+                let mut new_addr = unification_pair.addr.clone();
+                if let Some(rhs_enum_repr) = rhs_enum_repr.as_ref() {
+                    if let Some(lhs_enum_repr) = lhs_enum_repr.as_ref() {
+                        let _enum_repr_ψ = self.eval_subtype(SugaredUnificationPair { addr: new_addr.clone(), lhs: *lhs_enum_repr.clone(), rhs: *rhs_enum_repr.clone() })?;
+                    } else {
+                        return Err(SugaredUnificationError{ addr: new_addr, t1: unification_pair.lhs, t2: unification_pair.rhs });
+                    }
+                }
+
                 if lhs_variants.len() == rhs_variants.len() {
                     let mut halo_variants = Vec::new();
                     for (i,