Merge #1796

1796: Support completion for macros r=matklad a=uHOOCCOOHu

This is based on #1795 , and fixes #1727 

Also prettify hover text of macros.

Some screenshorts below:

Completion in item place.
<img width="416" alt="Screenshot_20190910_134056" src="https://user-images.githubusercontent.com/14816024/64587159-fa72da00-d3d0-11e9-86bb-c98f169ec08d.png">

After pressing `tab`.
<img width="313" alt="Screenshot_20190910_134111" src="https://user-images.githubusercontent.com/14816024/64587160-fa72da00-d3d0-11e9-9464-21e3f6957bd7.png">

Complete macros from `std`.
<img width="588" alt="Screenshot_20190910_134147" src="https://user-images.githubusercontent.com/14816024/64587161-fb0b7080-d3d0-11e9-866e-5161f0d1b546.png">

Hover text.
<img width="521" alt="Screenshot_20190910_134242" src="https://user-images.githubusercontent.com/14816024/64587162-fb0b7080-d3d0-11e9-8f09-ad17e3f6702a.png">



Co-authored-by: uHOOCCOOHu <[email protected]>

1 files changed, 7 insertions, 1 deletions

diff --git a/crates/ra_ide_api/src/display.rs b/crates/ra_ide_api/src/display.rs
index cc59e99d8..a980c56bc 100644
--- a/crates/ra_ide_api/src/display.rs
+++ b/crates/ra_ide_api/src/display.rs
@@ -7,7 +7,7 @@ mod structure;
 mod short_label;
 
 use ra_syntax::{
-    ast::{self, AstNode, TypeParamsOwner},
+    ast::{self, AstNode, AttrsOwner, NameOwner, TypeParamsOwner},
     SyntaxKind::{ATTR, COMMENT},
 };
 
@@ -61,6 +61,12 @@ pub(crate) fn where_predicates<N: TypeParamsOwner>(node: &N) -> Vec<String> {
     res
 }
 
+pub(crate) fn macro_label(node: &ast::MacroCall) -> String {
+    let name = node.name().map(|name| name.syntax().text().to_string()).unwrap_or_default();
+    let vis = if node.has_atom_attr("macro_export") { "#[macro_export]\n" } else { "" };
+    format!("{}macro_rules! {}", vis, name)
+}
+
 pub(crate) fn rust_code_markup<CODE: AsRef<str>>(val: CODE) -> String {
     rust_code_markup_with_doc::<_, &str>(val, None)
 }