1 files changed, 20 insertions, 3 deletions

diff --git a/crates/ra_hir/src/from_source.rs b/crates/ra_hir/src/from_source.rs
index 437f800c1..686ab1d79 100644
--- a/crates/ra_hir/src/from_source.rs
+++ b/crates/ra_hir/src/from_source.rs
@@ -1,7 +1,7 @@
 //! FIXME: write short doc here
 use hir_def::{
     child_by_source::ChildBySource, dyn_map::DynMap, keys, nameres::ModuleSource, AstItemDef,
-    EnumVariantId, LocationCtx, ModuleId, VariantId,
+    EnumVariantId, GenericDefId, LocationCtx, ModuleId, VariantId,
 };
 use hir_expand::{name::AsName, AstId, MacroDefId, MacroDefKind};
 use ra_syntax::{
@@ -11,8 +11,8 @@ use ra_syntax::{
 
 use crate::{
     db::{AstDatabase, DefDatabase, HirDatabase},
-    Const, DefWithBody, Enum, EnumVariant, FieldSource, Function, ImplBlock, InFile, Local,
-    MacroDef, Module, Static, Struct, StructField, Trait, TypeAlias, Union,
+    Const, DefWithBody, Enum, EnumVariant, FieldSource, Function, GenericParam, ImplBlock, InFile,
+    Local, MacroDef, Module, Static, Struct, StructField, Trait, TypeAlias, Union,
 };
 
 pub trait FromSource: Sized {
@@ -177,6 +177,23 @@ impl Local {
     }
 }
 
+impl GenericParam {
+    pub fn from_source(db: &impl HirDatabase, src: InFile<ast::TypeParam>) -> Option<Self> {
+        let file_id = src.file_id;
+        let parent: GenericDefId = src.value.syntax().ancestors().find_map(|it| {
+            let res = match_ast! {
+                match it {
+                    ast::FnDef(value) => { Function::from_source(db, InFile { value, file_id})?.id.into() },
+                    _ => return None,
+                }
+            };
+            Some(res)
+        })?;
+        let &id = parent.child_by_source(db)[keys::TYPE_PARAM].get(&src)?;
+        Some(GenericParam { id })
+    }
+}
+
 impl Module {
     pub fn from_declaration(db: &impl DefDatabase, src: InFile<ast::Module>) -> Option<Self> {
         let parent_declaration = src.value.syntax().ancestors().skip(1).find_map(ast::Module::cast);