Rollup merge of rust-lang#51146 - dlrobertson:fix_51102, r=estebank

typeck: Do not pass the field check on field error

If a struct pattern has a field error return an error.

Fixes: rust-lang#51102

Author: kennytm

src/librustc_typeck/check/_match.rs

@@ -720,8 +720,11 @@ https://doc.rust-lang.org/reference/types.html#trait-objects");
         self.demand_eqtype(pat.span, expected, pat_ty);
 
         // Type check subpatterns.
-        self.check_struct_pat_fields(pat_ty, pat.id, pat.span, variant, fields, etc, def_bm);
-        pat_ty
+        if self.check_struct_pat_fields(pat_ty, pat.id, pat.span, variant, fields, etc, def_bm) {
+            pat_ty
+        } else {
+            self.tcx.types.err
+        }
     }
 
     fn check_pat_path(&self,
@@ -846,7 +849,7 @@ https://doc.rust-lang.org/reference/types.html#trait-objects");
                                variant: &'tcx ty::VariantDef,
                                fields: &'gcx [Spanned<hir::FieldPat>],
                                etc: bool,
-                               def_bm: ty::BindingMode) {
+                               def_bm: ty::BindingMode) -> bool {
         let tcx = self.tcx;
 
         let (substs, adt) = match adt_ty.sty {
@@ -864,6 +867,7 @@ https://doc.rust-lang.org/reference/types.html#trait-objects");
 
         // Keep track of which fields have already appeared in the pattern.
         let mut used_fields = FxHashMap();
+        let mut no_field_errors = true;
 
         let mut inexistent_fields = vec![];
         // Typecheck each field.
@@ -879,6 +883,7 @@ https://doc.rust-lang.org/reference/types.html#trait-objects");
                                     format!("multiple uses of `{}` in pattern", field.ident))
                         .span_label(*occupied.get(), format!("first use of `{}`", field.ident))
                         .emit();
+                    no_field_errors = false;
                     tcx.types.err
                 }
                 Vacant(vacant) => {
@@ -891,6 +896,7 @@ https://doc.rust-lang.org/reference/types.html#trait-objects");
                         })
                         .unwrap_or_else(|| {
                             inexistent_fields.push((span, field.ident));
+                            no_field_errors = false;
                             tcx.types.err
                         })
                 }
@@ -989,5 +995,6 @@ https://doc.rust-lang.org/reference/types.html#trait-objects");
                 diag.emit();
             }
         }
+        no_field_errors
     }
 }

src/test/ui/issue-51102.rs

@@ -0,0 +1,48 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+enum SimpleEnum {
+    NoState,
+}
+
+struct SimpleStruct {
+    no_state_here: u64,
+}
+
+fn main() {
+    let _ = |simple| {
+        match simple {
+            SimpleStruct {
+                state: 0,
+                //~^ struct `SimpleStruct` does not have a field named `state` [E0026]
+                ..
+            } => (),
+        }
+    };
+
+    let _ = |simple| {
+        match simple {
+            SimpleStruct {
+                no_state_here: 0,
+                no_state_here: 1
+                //~^ ERROR field `no_state_here` bound multiple times in the pattern [E0025]
+            } => (),
+        }
+    };
+
+    let _ = |simple| {
+        match simple {
+            SimpleEnum::NoState {
+                state: 0
+                //~^ ERROR variant `SimpleEnum::NoState` does not have a field named `state` [E0026]
+            } => (),
+        }
+    };
+}

src/test/ui/issue-51102.stderr

@@ -0,0 +1,24 @@
+error[E0026]: struct `SimpleStruct` does not have a field named `state`
+  --> $DIR/issue-51102.rs:23:17
+   |
+LL |                 state: 0,
+   |                 ^^^^^^^^ struct `SimpleStruct` does not have this field
+
+error[E0025]: field `no_state_here` bound multiple times in the pattern
+  --> $DIR/issue-51102.rs:34:17
+   |
+LL |                 no_state_here: 0,
+   |                 ---------------- first use of `no_state_here`
+LL |                 no_state_here: 1
+   |                 ^^^^^^^^^^^^^^^^ multiple uses of `no_state_here` in pattern
+
+error[E0026]: variant `SimpleEnum::NoState` does not have a field named `state`
+  --> $DIR/issue-51102.rs:43:17
+   |
+LL |                 state: 0
+   |                 ^^^^^^^^ variant `SimpleEnum::NoState` does not have this field
+
+error: aborting due to 3 previous errors
+
+Some errors occurred: E0025, E0026.
+For more information about an error, try `rustc --explain E0025`.