hir, mir: Separate HIR expressions / MIR operands from InlineAsm.

[rust.git] / src / librustc_front / lowering.rs

diff --git a/src/librustc_front/lowering.rs b/src/librustc_front/lowering.rs
index acc7c6164b54ab9a3d0ed36443e7a07f7da2152a..8aac6356f9d3bf0f30ffceb50a7493012997e2ea 100644 (file)
--- a/src/librustc_front/lowering.rs
+++ b/src/librustc_front/lowering.rs
@@ -756,6 +756,7 @@ pub fn lower_impl_item(lctx: &LoweringContext, i: &ImplItem) -> hir::ImplItem {
         name: i.ident.name,
         attrs: lower_attrs(lctx, &i.attrs),
         vis: lower_visibility(lctx, i.vis),
+        defaultness: lower_defaultness(lctx, i.defaultness),
         node: match i.node {
             ImplItemKind::Const(ref ty, ref expr) => {
                 hir::ImplItemKind::Const(lower_ty(lctx, ty), lower_expr(lctx, expr))
@@ -1319,14 +1320,11 @@ fn make_struct(lctx: &LoweringContext,
                     dialect,
                     expn_id,
                 }) => hir::ExprInlineAsm(hir::InlineAsm {
-                inputs: inputs.iter()
-                              .map(|&(ref c, ref input)| (c.clone(), lower_expr(lctx, input)))
-                              .collect(),
+                inputs: inputs.iter().map(|&(ref c, _)| c.clone()).collect(),
                 outputs: outputs.iter()
                                 .map(|out| {
                                     hir::InlineAsmOutput {
                                         constraint: out.constraint.clone(),
-                                        expr: lower_expr(lctx, &out.expr),
                                         is_rw: out.is_rw,
                                         is_indirect: out.is_indirect,
                                     }
@@ -1339,7 +1337,8 @@ fn make_struct(lctx: &LoweringContext,
                 alignstack: alignstack,
                 dialect: dialect,
                 expn_id: expn_id,
-            }),
+            }, outputs.iter().map(|out| lower_expr(lctx, &out.expr)).collect(),
+               inputs.iter().map(|&(_, ref input)| lower_expr(lctx, input)).collect()),
             ExprKind::Struct(ref path, ref fields, ref maybe_expr) => {
                 hir::ExprStruct(lower_path(lctx, path),
                                 fields.iter().map(|x| lower_field(lctx, x)).collect(),
@@ -1605,6 +1604,63 @@ fn make_struct(lctx: &LoweringContext,
                 });
             }
 
+            // Desugar ExprKind::Try
+            // From: `<expr>?`
+            ExprKind::Try(ref sub_expr) => {
+                // to:
+                //
+                // {
+                //     match <expr> {
+                //         Ok(val) => val,
+                //         Err(err) => {
+                //             return Err(From::from(err))
+                //         }
+                //     }
+                // }
+
+                return cache_ids(lctx, e.id, |lctx| {
+                    // expand <expr>
+                    let sub_expr = lower_expr(lctx, sub_expr);
+
+                    // Ok(val) => val
+                    let ok_arm = {
+                        let val_ident = lctx.str_to_ident("val");
+                        let val_pat = pat_ident(lctx, e.span, val_ident);
+                        let val_expr = expr_ident(lctx, e.span, val_ident, None);
+                        let ok_pat = pat_ok(lctx, e.span, val_pat);
+
+                        arm(hir_vec![ok_pat], val_expr)
+                    };
+
+                    // Err(err) => return Err(From::from(err))
+                    let err_arm = {
+                        let err_ident = lctx.str_to_ident("err");
+                        let from_expr = {
+                            let path = std_path(lctx, &["convert", "From", "from"]);
+                            let path = path_global(e.span, path);
+                            let from = expr_path(lctx, path, None);
+                            let err_expr = expr_ident(lctx, e.span, err_ident, None);
+
+                            expr_call(lctx, e.span, from, hir_vec![err_expr], None)
+                        };
+                        let err_expr = {
+                            let path = std_path(lctx, &["result", "Result", "Err"]);
+                            let path = path_global(e.span, path);
+                            let err_ctor = expr_path(lctx, path, None);
+                            expr_call(lctx, e.span, err_ctor, hir_vec![from_expr], None)
+                        };
+                        let err_pat = pat_err(lctx, e.span, pat_ident(lctx, e.span, err_ident));
+                        let ret_expr = expr(lctx, e.span,
+                                            hir::Expr_::ExprRet(Some(err_expr)), None);
+
+                        arm(hir_vec![err_pat], ret_expr)
+                    };
+
+                    expr_match(lctx, e.span, sub_expr, hir_vec![err_arm, ok_arm],
+                               hir::MatchSource::TryDesugar, None)
+                })
+            }
+
             ExprKind::Mac(_) => panic!("Shouldn't exist here"),
         },
         span: e.span,
@@ -1650,6 +1706,13 @@ pub fn lower_visibility(_lctx: &LoweringContext, v: Visibility) -> hir::Visibili
     }
 }
 
+pub fn lower_defaultness(_lctx: &LoweringContext, d: Defaultness) -> hir::Defaultness {
+    match d {
+        Defaultness::Default => hir::Defaultness::Default,
+        Defaultness::Final => hir::Defaultness::Final,
+    }
+}
+
 pub fn lower_block_check_mode(lctx: &LoweringContext, b: &BlockCheckMode) -> hir::BlockCheckMode {
     match *b {
         BlockCheckMode::Default => hir::DefaultBlock,
@@ -1819,6 +1882,18 @@ fn block_all(lctx: &LoweringContext,
     })
 }
 
+fn pat_ok(lctx: &LoweringContext, span: Span, pat: P<hir::Pat>) -> P<hir::Pat> {
+    let ok = std_path(lctx, &["result", "Result", "Ok"]);
+    let path = path_global(span, ok);
+    pat_enum(lctx, span, path, hir_vec![pat])
+}
+
+fn pat_err(lctx: &LoweringContext, span: Span, pat: P<hir::Pat>) -> P<hir::Pat> {
+    let err = std_path(lctx, &["result", "Result", "Err"]);
+    let path = path_global(span, err);
+    pat_enum(lctx, span, path, hir_vec![pat])
+}
+
 fn pat_some(lctx: &LoweringContext, span: Span, pat: P<hir::Pat>) -> P<hir::Pat> {
     let some = std_path(lctx, &["option", "Option", "Some"]);
     let path = path_global(span, some);