---

Jorge Aparicio · Jorge Aparicio · commit 0301d537aeac · 2015-01-30T10:37:44.000-05:00
yaml --- r: 182904 b: refs/heads/beta c: 76362f0 h: refs/heads/master v: v3
diff --git a/[refs] b/[refs]
@@ -31,7 +31,7 @@ refs/heads/automation-fail: 1bf06495443584539b958873e04cc2f864ab10e4
 refs/heads/issue-18208-method-dispatch-3-quick-reject: 2009f85b9f99dedcec4404418eda9ddba90258a2
 refs/heads/batch: b7fd822592a4fb577552d93010c4a4e14f314346
 refs/heads/building: 126db549b038c84269a1e4fe46f051b2c15d6970
-refs/heads/beta: 5e1820f34611e311759518440fd4129c5f0c322a
+refs/heads/beta: 76362f0a0ee1b66d7df524c4c8dea9b15b45cf78
 refs/heads/windistfix: 7608dbad651f02e837ed05eef3d74a6662a6e928
 refs/tags/1.0.0-alpha: e42bd6d93a1d3433c486200587f8f9e12590a4d7
 refs/heads/tmp: eb836bf767aa1d8d4cba488a9091cde3c0ab4b2f
diff --git a/branches/beta/src/librustc/lint/builtin.rs b/branches/beta/src/librustc/lint/builtin.rs
@@ -1163,6 +1163,7 @@ impl LintPass for UnusedParens {
                 ast::MatchSource::Normal => (head, "`match` head expression", true),
                 ast::MatchSource::IfLetDesugar { .. } => (head, "`if let` head expression", true),
                 ast::MatchSource::WhileLetDesugar => (head, "`while let` head expression", true),
+                ast::MatchSource::ForLoopDesugar => (head, "`for` head expression", true),
             },
             ast::ExprRet(Some(ref value)) => (value, "`return` value", false),
             ast::ExprAssign(_, ref value) => (value, "assigned value", false),
diff --git a/branches/beta/src/librustc/middle/check_match.rs b/branches/beta/src/librustc/middle/check_match.rs
@@ -221,7 +221,7 @@ fn check_expr(cx: &mut MatchCheckCtxt, ex: &ast::Expr) {
                 .flat_map(|arm| arm.0.iter())
                 .map(|pat| vec![&**pat])
                 .collect();
-            check_exhaustive(cx, ex.span, &matrix);
+            check_exhaustive(cx, ex.span, &matrix, source);
         },
         ast::ExprForLoop(ref pat, _, _, _) => {
             let mut static_inliner = StaticInliner::new(cx.tcx);
@@ -327,6 +327,14 @@ fn check_arms(cx: &MatchCheckCtxt,
                             span_err!(cx.tcx.sess, span, E0165, "irrefutable while-let pattern");
                         },
 
+                        ast::MatchSource::ForLoopDesugar => {
+                            // this is a bug, because on `match iter.next()` we cover
+                            // `Some(<head>)` and `None`. It's impossible to have an unreachable
+                            // pattern
+                            // (see libsyntax/ext/expand.rs for the full expansion of a for loop)
+                            cx.tcx.sess.span_bug(pat.span, "unreachable for-loop pattern")
+                        },
+
                         ast::MatchSource::Normal => {
                             span_err!(cx.tcx.sess, pat.span, E0001, "unreachable pattern")
                         },
@@ -351,18 +359,37 @@ fn raw_pat<'a>(p: &'a Pat) -> &'a Pat {
     }
 }
 
-fn check_exhaustive(cx: &MatchCheckCtxt, sp: Span, matrix: &Matrix) {
+fn check_exhaustive(cx: &MatchCheckCtxt, sp: Span, matrix: &Matrix, source: ast::MatchSource) {
     match is_useful(cx, matrix, &[DUMMY_WILD_PAT], ConstructWitness) {
         UsefulWithWitness(pats) => {
             let witness = match &pats[] {
                 [ref witness] => &**witness,
                 [] => DUMMY_WILD_PAT,
                 _ => unreachable!()
             };
-            span_err!(cx.tcx.sess, sp, E0004,
-                "non-exhaustive patterns: `{}` not covered",
-                pat_to_string(witness)
-            );
+            match source {
+                ast::MatchSource::ForLoopDesugar => {
+                    // `witness` has the form `Some(<head>)`, peel off the `Some`
+                    let witness = match witness.node {
+                        ast::PatEnum(_, Some(ref pats)) => match &pats[] {
+                            [ref pat] => &**pat,
+                            _ => unreachable!(),
+                        },
+                        _ => unreachable!(),
+                    };
+
+                    span_err!(cx.tcx.sess, sp, E0297,
+                        "refutable pattern in `for` loop binding: \
+                                `{}` not covered",
+                                pat_to_string(witness));
+                },
+                _ => {
+                    span_err!(cx.tcx.sess, sp, E0004,
+                        "non-exhaustive patterns: `{}` not covered",
+                        pat_to_string(witness)
+                    );
+                },
+            }
         }
         NotUseful => {
             // This is good, wildcard pattern isn't reachable
diff --git a/branches/beta/src/librustc/util/ppaux.rs b/branches/beta/src/librustc/util/ppaux.rs
@@ -100,6 +100,7 @@ pub fn explain_region_and_span(cx: &ctxt, region: ty::Region)
               ast::ExprMethodCall(..) => "method call",
               ast::ExprMatch(_, _, ast::MatchSource::IfLetDesugar { .. }) => "if let",
               ast::ExprMatch(_, _, ast::MatchSource::WhileLetDesugar) =>  "while let",
+              ast::ExprMatch(_, _, ast::MatchSource::ForLoopDesugar) =>  "for",
               ast::ExprMatch(..) => "match",
               _ => "expression",
           },
diff --git a/branches/beta/src/libsyntax/ast.rs b/branches/beta/src/libsyntax/ast.rs
@@ -788,6 +788,7 @@ pub enum MatchSource {
     Normal,
     IfLetDesugar { contains_else_clause: bool },
     WhileLetDesugar,
+    ForLoopDesugar,
 }
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
diff --git a/branches/beta/src/libsyntax/ext/expand.rs b/branches/beta/src/libsyntax/ext/expand.rs
@@ -288,8 +288,8 @@ pub fn expand_expr(e: P<ast::Expr>, fld: &mut MacroExpander) -> P<ast::Expr> {
                     fld.cx.expr_call(span, fld.cx.expr_path(next_path), vec![ref_mut_iter]);
                 let arms = vec![pat_arm, break_arm];
 
-                // FIXME(japaric) This should use `ForLoopDesugar` as MatchSource
-                fld.cx.expr_match(pat_span, next_expr, arms)
+                fld.cx.expr(pat_span,
+                            ast::ExprMatch(next_expr, arms, ast::MatchSource::ForLoopDesugar))
             };
 
             // `[opt_ident]: loop { ... }`
diff --git a/branches/beta/src/test/compile-fail/for-loop-refutable-pattern-error-message.rs b/branches/beta/src/test/compile-fail/for-loop-refutable-pattern-error-message.rs
@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-
 fn main() {
     for
         &1is //~ ERROR refutable pattern in `for` loop binding

Original file line number	Diff line number	Diff line change
`@@ -788,6 +788,7 @@ pub enum MatchSource {`
`788`	`788`	`Normal,`
`789`	`789`	`IfLetDesugar { contains_else_clause: bool },`
`790`	`790`	`WhileLetDesugar,`
	`791`	`+ ForLoopDesugar,`
`791`	`792`	`}`
`792`	`793`
`793`	`794`	`#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]`