5 files changed, 52 insertions, 9 deletions

diff --git a/crates/ra_assists/src/handlers/add_explicit_type.rs b/crates/ra_assists/src/handlers/add_explicit_type.rs
index d86d804b2..6c56d93d8 100644
--- a/crates/ra_assists/src/handlers/add_explicit_type.rs
+++ b/crates/ra_assists/src/handlers/add_explicit_type.rs
@@ -52,21 +52,22 @@ pub(crate) fn add_explicit_type(ctx: AssistCtx) -> Option<Assist> {
     }
     // Infer type
     let ty = ctx.sema.type_of_expr(&expr)?;
-    // Assist not applicable if the type is unknown
-    if ty.contains_unknown() {
+
+    if ty.contains_unknown() || ty.is_closure() {
         return None;
     }
 
     let db = ctx.db;
+    let new_type_string = ty.display_truncated(db, None).to_string();
     ctx.add_assist(
         AssistId("add_explicit_type"),
-        format!("Insert explicit type '{}'", ty.display(db)),
+        format!("Insert explicit type '{}'", new_type_string),
         |edit| {
             edit.target(pat_range);
             if let Some(ascribed_ty) = ascribed_ty {
-                edit.replace(ascribed_ty.syntax().text_range(), format!("{}", ty.display(db)));
+                edit.replace(ascribed_ty.syntax().text_range(), new_type_string);
             } else {
-                edit.insert(name_range.end(), format!(": {}", ty.display(db)));
+                edit.insert(name_range.end(), format!(": {}", new_type_string));
             }
         },
     )
@@ -174,4 +175,41 @@ mod tests {
             "fn f() <|>{let a = match 1 {2 => 3, 3 => 5};}",
         )
     }
+
+    #[test]
+    fn closure_parameters_are_not_added() {
+        check_assist_not_applicable(
+            add_explicit_type,
+            r#"
+fn main() {
+    let multiply_by_two<|> = |i| i * 3;
+    let six = multiply_by_two(2);
+}"#,
+        )
+    }
+
+    #[test]
+    fn default_generics_should_not_be_added() {
+        check_assist(
+            add_explicit_type,
+            r#"
+struct Test<K, T = u8> {
+    k: K,
+    t: T,
+}
+
+fn main() {
+    let test<|> = Test { t: 23, k: 33 };
+}"#,
+            r#"
+struct Test<K, T = u8> {
+    k: K,
+    t: T,
+}
+
+fn main() {
+    let test<|>: Test<i32> = Test { t: 23, k: 33 };
+}"#,
+        );
+    }
 }
diff --git a/crates/ra_assists/src/handlers/add_from_impl_for_enum.rs b/crates/ra_assists/src/handlers/add_from_impl_for_enum.rs
index 864373aa5..0621487e8 100644
--- a/crates/ra_assists/src/handlers/add_from_impl_for_enum.rs
+++ b/crates/ra_assists/src/handlers/add_from_impl_for_enum.rs
@@ -98,7 +98,7 @@ fn already_has_from_impl(
     };
     let var_ty = hir_enum_var.fields(sema.db)[0].signature_ty(sema.db);
 
-    e_ty.impls_trait(sema.db, from_trait, &[var_ty.clone()])
+    e_ty.impls_trait(sema.db, from_trait, &[var_ty])
 }
 
 #[cfg(test)]
diff --git a/crates/ra_assists/src/handlers/introduce_variable.rs b/crates/ra_assists/src/handlers/introduce_variable.rs
index 8d0f7e922..8c09e6bcd 100644
--- a/crates/ra_assists/src/handlers/introduce_variable.rs
+++ b/crates/ra_assists/src/handlers/introduce_variable.rs
@@ -124,7 +124,7 @@ fn anchor_stmt(expr: ast::Expr) -> Option<(SyntaxNode, bool)> {
             }
         }
 
-        if ast::Stmt::cast(node.clone().into()).is_some() {
+        if ast::Stmt::cast(node.clone()).is_some() {
             return Some((node, false));
         }
 
diff --git a/crates/ra_assists/src/handlers/merge_imports.rs b/crates/ra_assists/src/handlers/merge_imports.rs
index ef0ce0586..4be1238f1 100644
--- a/crates/ra_assists/src/handlers/merge_imports.rs
+++ b/crates/ra_assists/src/handlers/merge_imports.rs
@@ -30,7 +30,7 @@ pub(crate) fn merge_imports(ctx: AssistCtx) -> Option<Assist> {
             .filter_map(|dir| neighbor(&use_item, dir))
             .filter_map(|it| Some((it.clone(), it.use_tree()?)))
             .find_map(|(use_item, use_tree)| {
-                Some((try_merge_trees(&tree, &use_tree)?, use_item.clone()))
+                Some((try_merge_trees(&tree, &use_tree)?, use_item))
             })?;
 
         rewriter.replace_ast(&tree, &merged);
diff --git a/crates/ra_assists/src/handlers/split_import.rs b/crates/ra_assists/src/handlers/split_import.rs
index d9244f22d..f25826796 100644
--- a/crates/ra_assists/src/handlers/split_import.rs
+++ b/crates/ra_assists/src/handlers/split_import.rs
@@ -37,7 +37,7 @@ pub(crate) fn split_import(ctx: AssistCtx) -> Option<Assist> {
 
 #[cfg(test)]
 mod tests {
-    use crate::helpers::{check_assist, check_assist_target};
+    use crate::helpers::{check_assist, check_assist_not_applicable, check_assist_target};
 
     use super::*;
 
@@ -63,4 +63,9 @@ mod tests {
     fn split_import_target() {
         check_assist_target(split_import, "use crate::<|>db::{RootDatabase, FileSymbol}", "::");
     }
+
+    #[test]
+    fn issue4044() {
+        check_assist_not_applicable(split_import, "use crate::<|>:::self;")
+    }
 }