Better complete expression keywords

crates/ra_ide/src/completion/complete_keyword.rs

@@ -92,20 +92,18 @@ pub(super) fn complete_expr_keyword(acc: &mut Completions, ctx: &CompletionConte
         add_keyword(ctx, acc, "union", "union $0 {}");
     }
 
-    if ctx.block_expr_parent || ctx.is_match_arm {
+    if ctx.can_be_expr {
         add_keyword(ctx, acc, "match", "match $0 {}");
-        add_keyword(ctx, acc, "loop", "loop {$0}");
-    }
-    if ctx.block_expr_parent {
         add_keyword(ctx, acc, "while", "while $0 {}");
-    }
+        add_keyword(ctx, acc, "loop", "loop {$0}");
-    if ctx.if_is_prev || ctx.block_expr_parent {
-        add_keyword(ctx, acc, "let", "let ");
-    }
-    if ctx.if_is_prev || ctx.block_expr_parent || ctx.is_match_arm {
         add_keyword(ctx, acc, "if", "if ");
         add_keyword(ctx, acc, "if let", "if let ");
     }
+
+    if ctx.if_is_prev || ctx.block_expr_parent {
+        add_keyword(ctx, acc, "let", "let ");
+    }
+
     if ctx.after_if {
         add_keyword(ctx, acc, "else", "else {$0}");
         add_keyword(ctx, acc, "else if", "else if $0 {}");
@@ -343,9 +341,7 @@ mod tests {
         check(
             r#"
 fn quux() -> i32 {
-    match () {
+    match () { () => <|> }
-        () => <|>
-    }
 }
 "#,
             expect![[r#"
@@ -355,6 +351,7 @@ fn quux() -> i32 {
                 kw match
                 kw return
                 kw unsafe
+                kw while
             "#]],
         );
     }
@@ -525,4 +522,19 @@ pub mod future {
             "#]],
         )
     }
+
+    #[test]
+    fn after_let() {
+        check(
+            r#"fn main() { let _ = <|> }"#,
+            expect![[r#"
+                kw if
+                kw if let
+                kw loop
+                kw match
+                kw return
+                kw while
+            "#]],
+        )
+    }
 }

crates/ra_ide/src/completion/completion_context.rs

@@ -53,6 +53,8 @@ pub(crate) struct CompletionContext<'a> {
     pub(super) after_if: bool,
     /// `true` if we are a statement or a last expr in the block.
     pub(super) can_be_stmt: bool,
+    /// `true` if we expect an expression at the cursor position.
+    pub(super) can_be_expr: bool,
     /// Something is typed at the "top" level, in module or impl/trait.
     pub(super) is_new_item: bool,
     /// The receiver if this is a field or method access, i.e. writing something.<|>
@@ -127,6 +129,7 @@ impl<'a> CompletionContext<'a> {
             path_prefix: None,
             after_if: false,
             can_be_stmt: false,
+            can_be_expr: false,
             is_new_item: false,
             dot_receiver: None,
             is_call: false,
@@ -403,6 +406,7 @@ impl<'a> CompletionContext<'a> {
                         None
                     })
                     .unwrap_or(false);
+                self.can_be_expr = path.syntax().parent().and_then(ast::PathExpr::cast).is_some();
 
                 if let Some(off) = name_ref.syntax().text_range().start().checked_sub(2.into()) {
                     if let Some(if_expr) =