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, 23 insertions, 1 deletions

diff --git a/crates/ra_ide_api/src/completion/presentation.rs b/crates/ra_ide_api/src/completion/presentation.rs
index db7e8348e..1b706bb13 100644
--- a/crates/ra_ide_api/src/completion/presentation.rs
+++ b/crates/ra_ide_api/src/completion/presentation.rs
@@ -8,7 +8,7 @@ use crate::completion::{
     CompletionContext, CompletionItem, CompletionItemKind, CompletionKind, Completions,
 };
 
-use crate::display::{const_label, function_label, type_label};
+use crate::display::{const_label, function_label, macro_label, type_label};
 
 impl Completions {
     pub(crate) fn add_field(
@@ -43,8 +43,14 @@ impl Completions {
     ) {
         use hir::ModuleDef::*;
 
+        if let Some(macro_) = resolution.get_macros() {
+            self.add_macro(ctx, Some(local_name.clone()), macro_);
+        }
+
         let def = resolution.as_ref().take_types().or_else(|| resolution.as_ref().take_values());
         let def = match def {
+            // Only insert once if it is just a macro name
+            None if resolution.get_macros().is_some() => return,
             None => {
                 self.add(CompletionItem::new(
                     CompletionKind::Reference,
@@ -98,6 +104,22 @@ impl Completions {
         self.add_function_with_name(ctx, None, func)
     }
 
+    fn add_macro(&mut self, ctx: &CompletionContext, name: Option<String>, macro_: hir::MacroDef) {
+        let ast_node = macro_.source(ctx.db).ast;
+        if let Some(name) = name {
+            let detail = macro_label(&ast_node);
+
+            let builder =
+                CompletionItem::new(CompletionKind::Reference, ctx.source_range(), name.clone())
+                    .kind(CompletionItemKind::Macro)
+                    .set_documentation(macro_.docs(ctx.db))
+                    .detail(detail)
+                    .insert_snippet(format!("{}!", name));
+
+            self.add(builder);
+        }
+    }
+
     fn add_function_with_name(
         &mut self,
         ctx: &CompletionContext,