Add better assertion messages

src/bindgen/cdecl.rs

@@ -69,22 +69,22 @@ impl CDecl {
         match t {
             &Type::Path(ref path) => {
                 if is_const {
-                    assert!(self.type_qualifers.len() == 0);
+                    assert!(self.type_qualifers.len() == 0, "error generating cdecl for {:?}", t);
                     self.type_qualifers = "const".to_owned();
                 }
 
-                assert!(self.type_name.len() == 0);
+                assert!(self.type_name.len() == 0, "error generating cdecl for {:?}", t);
                 self.type_name = path.name.clone();
-                assert!(self.type_generic_args.len() == 0);
+                assert!(self.type_generic_args.len() == 0, "error generating cdecl for {:?}", t);
                 self.type_generic_args = path.generics.clone();
             }
             &Type::Primitive(ref p) => {
                 if is_const {
-                    assert!(self.type_qualifers.len() == 0);
+                    assert!(self.type_qualifers.len() == 0, "error generating cdecl for {:?}", t);
                     self.type_qualifers = "const".to_owned();
                 }
 
-                assert!(self.type_name.len() == 0);
+                assert!(self.type_name.len() == 0, "error generating cdecl for {:?}", t);
                 self.type_name = p.to_string();
             }
 

src/bindgen/ir/opaque.rs

@@ -74,7 +74,12 @@ impl Item for OpaqueItem {
         _library: &Library,
         out: &mut Monomorphs,
     ) {
-        assert!(self.generic_params.len() > 0 && self.generic_params.len() == generic_values.len());
+        assert!(self.generic_params.len() > 0, "{} is not generic", self.name);
+        assert!(self.generic_params.len() == generic_values.len(), "{} has {} params but is being instantiated with {} values",
+            self.name,
+            self.generic_params.len(),
+            generic_values.len(),
+        );
 
         let monomorph = OpaqueItem {
             name: mangle::mangle_path(&self.name, generic_values),

src/bindgen/ir/path.rs

@@ -24,7 +24,7 @@ impl GenericPath {
     }
 
     pub fn load(path: &syn::Path) -> Result<GenericPath, String> {
-        assert!(path.segments.len() > 0);
+        assert!(path.segments.len() > 0, "{:?} doesn't have any segments", path);
         let last_segment_token = path.segments.last().unwrap();
         let last_segment = last_segment_token.value();
         let name = last_segment.ident.to_string();

src/bindgen/ir/structure.rs

@@ -176,7 +176,12 @@ impl Item for Struct {
         library: &Library,
         out: &mut Monomorphs,
     ) {
-        assert!(self.generic_params.len() > 0 && self.generic_params.len() == generic_values.len());
+        assert!(self.generic_params.len() > 0, "{} is not generic", self.name);
+        assert!(self.generic_params.len() == generic_values.len(), "{} has {} params but is being instantiated with {} values",
+            self.name,
+            self.generic_params.len(),
+            generic_values.len(),
+        );
 
         let mappings = self.generic_params
             .iter()

src/bindgen/ir/typedef.rs

@@ -125,7 +125,12 @@ impl Item for Typedef {
         library: &Library,
         out: &mut Monomorphs,
     ) {
-        assert!(self.generic_params.len() > 0 && self.generic_params.len() == generic_values.len());
+        assert!(self.generic_params.len() > 0, "{} is not generic", self.name);
+        assert!(self.generic_params.len() == generic_values.len(), "{} has {} params but is being instantiated with {} values",
+            self.name,
+            self.generic_params.len(),
+            generic_values.len(),
+        );
 
         let mappings = self.generic_params
             .iter()

src/bindgen/ir/union.rs

@@ -165,7 +165,12 @@ impl Item for Union {
         library: &Library,
         out: &mut Monomorphs,
     ) {
-        assert!(self.generic_params.len() > 0 && self.generic_params.len() == generic_values.len());
+        assert!(self.generic_params.len() > 0, "{} is not generic", self.name);
+        assert!(self.generic_params.len() == generic_values.len(), "{} has {} params but is being instantiated with {} values",
+            self.name,
+            self.generic_params.len(),
+            generic_values.len(),
+        );
 
         let mappings = self.generic_params
             .iter()