1 files changed, 132 insertions, 72 deletions

diff --git a/crates/ra_assists/src/handlers/add_function.rs b/crates/ra_assists/src/handlers/add_function.rs
index 278079665..de016ae4e 100644
--- a/crates/ra_assists/src/handlers/add_function.rs
+++ b/crates/ra_assists/src/handlers/add_function.rs
@@ -1,14 +1,17 @@
+use hir::HirDisplay;
+use ra_db::FileId;
 use ra_syntax::{
-    ast::{self, AstNode},
+    ast::{
+        self,
+        edit::{AstNodeEdit, IndentLevel},
+        ArgListOwner, AstNode, ModuleItemOwner,
+    },
     SyntaxKind, SyntaxNode, TextSize,
 };
-
-use crate::{Assist, AssistCtx, AssistId};
-use ast::{edit::IndentLevel, ArgListOwner, ModuleItemOwner};
-use hir::HirDisplay;
-use ra_db::FileId;
 use rustc_hash::{FxHashMap, FxHashSet};
 
+use crate::{AssistContext, AssistId, Assists};
+
 // Assist: add_function
 //
 // Adds a stub function with a signature matching the function under the cursor.
@@ -34,7 +37,7 @@ use rustc_hash::{FxHashMap, FxHashSet};
 // }
 //
 // ```
-pub(crate) fn add_function(ctx: AssistCtx) -> Option<Assist> {
+pub(crate) fn add_function(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
     let path_expr: ast::PathExpr = ctx.find_node_at_offset()?;
     let call = path_expr.syntax().parent().and_then(ast::CallExpr::cast)?;
     let path = path_expr.path()?;
@@ -44,22 +47,18 @@ pub(crate) fn add_function(ctx: AssistCtx) -> Option<Assist> {
         return None;
     }
 
-    let target_module = if let Some(qualifier) = path.qualifier() {
-        if let Some(hir::PathResolution::Def(hir::ModuleDef::Module(module))) =
-            ctx.sema.resolve_path(&qualifier)
-        {
-            Some(module.definition_source(ctx.sema.db))
-        } else {
-            return None;
-        }
-    } else {
-        None
+    let target_module = match path.qualifier() {
+        Some(qualifier) => match ctx.sema.resolve_path(&qualifier) {
+            Some(hir::PathResolution::Def(hir::ModuleDef::Module(module))) => Some(module),
+            _ => return None,
+        },
+        None => None,
     };
 
     let function_builder = FunctionBuilder::from_call(&ctx, &call, &path, target_module)?;
 
     let target = call.syntax().text_range();
-    ctx.add_assist(AssistId("add_function"), "Add function", target, |edit| {
+    acc.add(AssistId("add_function"), "Add function", target, |edit| {
         let function_template = function_builder.render();
         edit.set_file(function_template.file);
         edit.set_cursor(function_template.cursor_offset);
@@ -84,25 +83,29 @@ struct FunctionBuilder {
 }
 
 impl FunctionBuilder {
-    /// Prepares a generated function that matches `call` in `generate_in`
-    /// (or as close to `call` as possible, if `generate_in` is `None`)
+    /// Prepares a generated function that matches `call`.
+    /// The function is generated in `target_module` or next to `call`
     fn from_call(
-        ctx: &AssistCtx,
+        ctx: &AssistContext,
         call: &ast::CallExpr,
         path: &ast::Path,
-        target_module: Option<hir::InFile<hir::ModuleSource>>,
+        target_module: Option<hir::Module>,
     ) -> Option<Self> {
-        let needs_pub = target_module.is_some();
         let mut file = ctx.frange.file_id;
-        let target = if let Some(target_module) = target_module {
-            let (in_file, target) = next_space_for_fn_in_module(ctx.sema.db, target_module)?;
-            file = in_file;
-            target
-        } else {
-            next_space_for_fn_after_call_site(&call)?
+        let target = match &target_module {
+            Some(target_module) => {
+                let module_source = target_module.definition_source(ctx.db);
+                let (in_file, target) = next_space_for_fn_in_module(ctx.sema.db, &module_source)?;
+                file = in_file;
+                target
+            }
+            None => next_space_for_fn_after_call_site(&call)?,
         };
+        let needs_pub = target_module.is_some();
+        let target_module = target_module.or_else(|| ctx.sema.scope(target.syntax()).module())?;
         let fn_name = fn_name(&path)?;
-        let (type_params, params) = fn_args(ctx, &call)?;
+        let (type_params, params) = fn_args(ctx, target_module, &call)?;
+
         Some(Self { target, fn_name, type_params, params, file, needs_pub })
     }
 
@@ -117,17 +120,16 @@ impl FunctionBuilder {
         let (fn_def, insert_offset) = match self.target {
             GeneratedFunctionTarget::BehindItem(it) => {
                 let with_leading_blank_line = ast::make::add_leading_newlines(2, fn_def);
-                let indented = IndentLevel::from_node(&it).increase_indent(with_leading_blank_line);
+                let indented = with_leading_blank_line.indent(IndentLevel::from_node(&it));
                 (indented, it.text_range().end())
             }
             GeneratedFunctionTarget::InEmptyItemList(it) => {
                 let indent_once = IndentLevel(1);
                 let indent = IndentLevel::from_node(it.syntax());
-
                 let fn_def = ast::make::add_leading_newlines(1, fn_def);
-                let fn_def = indent_once.increase_indent(fn_def);
+                let fn_def = fn_def.indent(indent_once);
                 let fn_def = ast::make::add_trailing_newlines(1, fn_def);
-                let fn_def = indent.increase_indent(fn_def);
+                let fn_def = fn_def.indent(indent);
                 (fn_def, it.syntax().text_range().start() + TextSize::of('{'))
             }
         };
@@ -145,6 +147,15 @@ enum GeneratedFunctionTarget {
     InEmptyItemList(ast::ItemList),
 }
 
+impl GeneratedFunctionTarget {
+    fn syntax(&self) -> &SyntaxNode {
+        match self {
+            GeneratedFunctionTarget::BehindItem(it) => it,
+            GeneratedFunctionTarget::InEmptyItemList(it) => it.syntax(),
+        }
+    }
+}
+
 fn fn_name(call: &ast::Path) -> Option<ast::Name> {
     let name = call.segment()?.syntax().to_string();
     Some(ast::make::name(&name))
@@ -152,18 +163,18 @@ fn fn_name(call: &ast::Path) -> Option<ast::Name> {
 
 /// Computes the type variables and arguments required for the generated function
 fn fn_args(
-    ctx: &AssistCtx,
+    ctx: &AssistContext,
+    target_module: hir::Module,
     call: &ast::CallExpr,
 ) -> Option<(Option<ast::TypeParamList>, ast::ParamList)> {
     let mut arg_names = Vec::new();
     let mut arg_types = Vec::new();
     for arg in call.arg_list()?.args() {
-        let arg_name = match fn_arg_name(&arg) {
+        arg_names.push(match fn_arg_name(&arg) {
             Some(name) => name,
             None => String::from("arg"),
-        };
-        arg_names.push(arg_name);
-        arg_types.push(match fn_arg_type(ctx, &arg) {
+        });
+        arg_types.push(match fn_arg_type(ctx, target_module, &arg) {
             Some(ty) => ty,
             None => String::from("()"),
         });
@@ -219,12 +230,21 @@ fn fn_arg_name(fn_arg: &ast::Expr) -> Option<String> {
     }
 }
 
-fn fn_arg_type(ctx: &AssistCtx, fn_arg: &ast::Expr) -> Option<String> {
+fn fn_arg_type(
+    ctx: &AssistContext,
+    target_module: hir::Module,
+    fn_arg: &ast::Expr,
+) -> Option<String> {
     let ty = ctx.sema.type_of_expr(fn_arg)?;
     if ty.is_unknown() {
         return None;
     }
-    Some(ty.display(ctx.sema.db).to_string())
+
+    if let Ok(rendered) = ty.display_source_code(ctx.db, target_module.into()) {
+        Some(rendered)
+    } else {
+        None
+    }
 }
 
 /// Returns the position inside the current mod or file
@@ -253,10 +273,10 @@ fn next_space_for_fn_after_call_site(expr: &ast::CallExpr) -> Option<GeneratedFu
 
 fn next_space_for_fn_in_module(
     db: &dyn hir::db::AstDatabase,
-    module: hir::InFile<hir::ModuleSource>,
+    module_source: &hir::InFile<hir::ModuleSource>,
 ) -> Option<(FileId, GeneratedFunctionTarget)> {
-    let file = module.file_id.original_file(db);
-    let assist_item = match module.value {
+    let file = module_source.file_id.original_file(db);
+    let assist_item = match &module_source.value {
         hir::ModuleSource::SourceFile(it) => {
             if let Some(last_item) = it.items().last() {
                 GeneratedFunctionTarget::BehindItem(last_item.syntax().clone())
@@ -600,8 +620,33 @@ fn bar(foo: impl Foo) {
     }
 
     #[test]
-    #[ignore]
-    // FIXME print paths properly to make this test pass
+    fn borrowed_arg() {
+        check_assist(
+            add_function,
+            r"
+struct Baz;
+fn baz() -> Baz { todo!() }
+
+fn foo() {
+    bar<|>(&baz())
+}
+",
+            r"
+struct Baz;
+fn baz() -> Baz { todo!() }
+
+fn foo() {
+    bar(&baz())
+}
+
+fn bar(baz: &Baz) {
+    <|>todo!()
+}
+",
+        )
+    }
+
+    #[test]
     fn add_function_with_qualified_path_arg() {
         check_assist(
             add_function,
@@ -610,10 +655,8 @@ mod Baz {
     pub struct Bof;
     pub fn baz() -> Bof { Bof }
 }
-mod Foo {
-    fn foo() {
-        <|>bar(super::Baz::baz())
-    }
+fn foo() {
+    <|>bar(Baz::baz())
 }
 ",
             r"
@@ -621,14 +664,12 @@ mod Baz {
     pub struct Bof;
     pub fn baz() -> Bof { Bof }
 }
-mod Foo {
-    fn foo() {
-        bar(super::Baz::baz())
-    }
+fn foo() {
+    bar(Baz::baz())
+}
 
-    fn bar(baz: super::Baz::Bof) {
-        <|>todo!()
-    }
+fn bar(baz: Baz::Bof) {
+    <|>todo!()
 }
 ",
         )
@@ -810,6 +851,40 @@ fn foo() {
     }
 
     #[test]
+    #[ignore]
+    // Ignored until local imports are supported.
+    // See https://github.com/rust-analyzer/rust-analyzer/issues/1165
+    fn qualified_path_uses_correct_scope() {
+        check_assist(
+            add_function,
+            "
+mod foo {
+    pub struct Foo;
+}
+fn bar() {
+    use foo::Foo;
+    let foo = Foo;
+    baz<|>(foo)
+}
+",
+            "
+mod foo {
+    pub struct Foo;
+}
+fn bar() {
+    use foo::Foo;
+    let foo = Foo;
+    baz(foo)
+}
+
+fn baz(foo: foo::Foo) {
+    <|>todo!()
+}
+",
+        )
+    }
+
+    #[test]
     fn add_function_in_module_containing_other_items() {
         check_assist(
             add_function,
@@ -921,21 +996,6 @@ fn bar(baz: ()) {}
     }
 
     #[test]
-    fn add_function_not_applicable_if_function_path_not_singleton() {
-        // In the future this assist could be extended to generate functions
-        // if the path is in the same crate (or even the same workspace).
-        // For the beginning, I think this is fine.
-        check_assist_not_applicable(
-            add_function,
-            r"
-fn foo() {
-    other_crate::bar<|>();
-}
-        ",
-        )
-    }
-
-    #[test]
     #[ignore]
     fn create_method_with_no_args() {
         check_assist(