Adds support for multiple errors from the resolver (#247)

* Adds support for multiple errors from the resolver

* Add missing test assertion

Author: popematt

ion-schema/src/model/constraints/annotations/v2_simple.rs

@@ -111,9 +111,9 @@ impl TypeDefinitionBuilder<ISL_2_0> {
     ///
     /// # Arguments
     /// * `modifier` - An [`AnnotationsV2Modifier`] that specifies how the annotations should be applied
-    ///               (e.g., required, closed, or both)
+    ///   (e.g., required, closed, or both)
     /// * `annotations` - An iterable collection of items that can be converted into [`Symbol`],
-    ///                  representing the annotation names
+    ///   representing the annotation names
     ///
     /// # Returns
     /// * Returns `Self` to allow for method chaining in the builder pattern

ion-schema/src/model/schema_header.rs

@@ -94,6 +94,22 @@ impl Import {
             .and_then(|type_import| type_import.alias.as_deref())
     }
 }
+impl Display for Import {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.write_str("{id:")?;
+        f.write_str(&self.schema_id)?;
+        if let Some(name) = self.type_name() {
+            f.write_str(",type:")?;
+            f.write_str(name)?;
+            if let Some(alias) = self.type_alias() {
+                f.write_str(",as:")?;
+                f.write_str(alias)?;
+            }
+        }
+        f.write_char('}')?;
+        Ok(())
+    }
+}
 impl HasIslSourceLocation for Import {
     fn isl_source_location(&self) -> IslSourceLocation {
         self.source_location

ion-schema/src/resolver/mod.rs

@@ -13,7 +13,7 @@ pub use resolved_schema::*;
 pub(crate) use type_ref_visitor::*;
 
 /// A schema index and type index.
-#[derive(Copy, Clone, Debug, Ord, PartialOrd, Eq, PartialEq)]
+#[derive(Copy, Clone, Debug, Ord, PartialOrd, Eq, PartialEq, Hash)]
 pub(crate) struct TypeCoordinates(usize, usize);
 impl TypeCoordinates {
     #[cfg(test)]