From 4992d2bf79e9da6db759eb8e1715f90f31ec7eb9 Mon Sep 17 00:00:00 2001
From: oxalica <oxalicc@pm.me>
Date: Fri, 29 Nov 2019 03:10:16 +0800
Subject: Infer range types

---
 crates/ra_hir_def/src/body/lower.rs | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

(limited to 'crates/ra_hir_def/src/body/lower.rs')

diff --git a/crates/ra_hir_def/src/body/lower.rs b/crates/ra_hir_def/src/body/lower.rs
index 331736cb2..d18964d54 100644
--- a/crates/ra_hir_def/src/body/lower.rs
+++ b/crates/ra_hir_def/src/body/lower.rs
@@ -8,7 +8,7 @@ use hir_expand::{
 use ra_arena::Arena;
 use ra_syntax::{
     ast::{
-        self, ArgListOwner, ArrayExprKind, LiteralKind, LoopBodyOwner, NameOwner,
+        self, ArgListOwner, ArrayExprKind, LiteralKind, LoopBodyOwner, NameOwner, RangeOp,
         TypeAscriptionOwner,
     },
     AstNode, AstPtr,
@@ -429,10 +429,28 @@ where
                 let index = self.collect_expr_opt(e.index());
                 self.alloc_expr(Expr::Index { base, index }, syntax_ptr)
             }
+            ast::Expr::RangeExpr(e) => {
+                let lhs = e.start().map(|lhs| self.collect_expr(lhs));
+                let rhs = e.end().map(|rhs| self.collect_expr(rhs));
+                match (lhs, e.op_kind(), rhs) {
+                    (None, _, None) => self.alloc_expr(Expr::RangeFull, syntax_ptr),
+                    (Some(lhs), _, None) => self.alloc_expr(Expr::RangeFrom { lhs }, syntax_ptr),
+                    (None, Some(RangeOp::Inclusive), Some(rhs)) => {
+                        self.alloc_expr(Expr::RangeToInclusive { rhs }, syntax_ptr)
+                    }
+                    (Some(lhs), Some(RangeOp::Inclusive), Some(rhs)) => {
+                        self.alloc_expr(Expr::RangeInclusive { lhs, rhs }, syntax_ptr)
+                    }
+                    // If RangeOp is missing, fallback to exclusive range.
+                    (None, _, Some(rhs)) => self.alloc_expr(Expr::RangeTo { rhs }, syntax_ptr),
+                    (Some(lhs), _, Some(rhs)) => {
+                        self.alloc_expr(Expr::Range { lhs, rhs }, syntax_ptr)
+                    }
+                }
+            }
 
             // FIXME implement HIR for these:
             ast::Expr::Label(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
-            ast::Expr::RangeExpr(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
             ast::Expr::MacroCall(e) => match self.expander.enter_expand(self.db, e) {
                 Some((mark, expansion)) => {
                     let id = self.collect_expr(expansion);
-- 
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