TemplateParameters.num_self_template_params doesn't return Option

Author: tamird

src/ir/context.rs

@@ -1549,15 +1549,16 @@ impl BindgenContext {
             .and_then(|canon_decl| {
                 self.get_resolved_type(&canon_decl).and_then(
                     |template_decl_id| {
-                        template_decl_id.num_self_template_params(self).map(
-                            |num_params| {
-                                (
-                                    *canon_decl.cursor(),
-                                    template_decl_id.into(),
-                                    num_params,
-                                )
-                            },
-                        )
+                        let num_params = template_decl_id.num_self_template_params(self);
+                        if num_params == 0 {
+                            None
+                        } else {
+                            Some((
+                                *canon_decl.cursor(),
+                                template_decl_id.into(),
+                                num_params,
+                            ))
+                        }
                     },
                 )
             })
@@ -1578,15 +1579,16 @@ impl BindgenContext {
                             .cloned()
                     })
                     .and_then(|template_decl| {
-                        template_decl.num_self_template_params(self).map(
-                            |num_template_params| {
-                                (
-                                    *template_decl.decl(),
-                                    template_decl.id(),
-                                    num_template_params,
-                                )
-                            },
-                        )
+                        let num_template_params = template_decl.num_self_template_params(self);
+                        if num_template_params == 0 {
+                            None
+                        } else {
+                            Some((
+                                *template_decl.decl(),
+                                template_decl.id(),
+                                num_template_params,
+                            ))
+                        }
                     })
             })
     }
@@ -1633,17 +1635,14 @@ impl BindgenContext {
     ) -> Option<TypeId> {
         use clang_sys;
 
-        let num_expected_args = match self.resolve_type(template)
-            .num_self_template_params(self) {
-            Some(n) => n,
-            None => {
-                warn!(
-                    "Tried to instantiate a template for which we could not \
-                       determine any template parameters"
-                );
-                return None;
-            }
-        };
+        let num_expected_args = self.resolve_type(template).num_self_template_params(self);
+        if num_expected_args == 0 {
+            warn!(
+                "Tried to instantiate a template for which we could not \
+                   determine any template parameters"
+            );
+            return None;
+        }
 
         let mut args = vec![];
         let mut found_const_arg = false;
@@ -2650,7 +2649,7 @@ impl TemplateParameters for PartialType {
         vec![]
     }
 
-    fn num_self_template_params(&self, _ctx: &BindgenContext) -> Option<usize> {
+    fn num_self_template_params(&self, _ctx: &BindgenContext) -> usize {
         // Wouldn't it be nice if libclang would reliably give us this
         // information‽
         match self.decl().kind() {
@@ -2669,9 +2668,9 @@ impl TemplateParameters for PartialType {
                     };
                     clang_sys::CXChildVisit_Continue
                 });
-                Some(num_params)
+                num_params
             }
-            _ => None,
+            _ => 0,
         }
     }
 }

src/ir/template.rs

@@ -81,12 +81,12 @@ use parse::ClangItemParser;
 /// +------+----------------------+--------------------------+------------------------+----
 /// |Decl. | self_template_params | num_self_template_params | all_template_parameters| ...
 /// +------+----------------------+--------------------------+------------------------+----
-/// |Foo   | [T, U]               | Some(2)                  | Some([T, U])           | ...
-/// |Bar   | [V]                  | Some(1)                  | Some([T, U, V])        | ...
-/// |Inner | []                   | None                     | Some([T, U])           | ...
-/// |Lol   | [W]                  | Some(1)                  | Some([T, U, W])        | ...
-/// |Wtf   | [X]                  | Some(1)                  | Some([T, U, X])        | ...
-/// |Qux   | []                   | None                     | None                   | ...
+/// |Foo   | [T, U]               | 2                        | Some([T, U])           | ...
+/// |Bar   | [V]                  | 1                        | Some([T, U, V])        | ...
+/// |Inner | []                   | 0                        | Some([T, U])           | ...
+/// |Lol   | [W]                  | 1                        | Some([T, U, W])        | ...
+/// |Wtf   | [X]                  | 1                        | Some([T, U, X])        | ...
+/// |Qux   | []                   | 0                        | None                   | ...
 /// +------+----------------------+--------------------------+------------------------+----
 ///
 /// ----+------+-----+----------------------+
@@ -113,18 +113,8 @@ pub trait TemplateParameters {
 
     /// Get the number of free template parameters this template declaration
     /// has.
-    ///
-    /// Implementations *may* return `Some` from this method when
-    /// `template_params` returns `None`. This is useful when we only have
-    /// partial information about the template declaration, such as when we are
-    /// in the middle of parsing it.
-    fn num_self_template_params(&self, ctx: &BindgenContext) -> Option<usize> {
-        let len = self.self_template_params(ctx).len();
-        if len > 0 {
-            Some(len)
-        } else {
-            None
-        }
+    fn num_self_template_params(&self, ctx: &BindgenContext) -> usize {
+        self.self_template_params(ctx).len()
     }
 
     /// Get the complete set of template parameters that can affect this