Rollup merge of #35480 - KiChjang:e0379-bonus, r=nikomatsakis

Move E0379 check from typeck to ast validation

Part of #35233.
Extension of #35338, #35364.
Fixes #35404.

8 files changed, 41 insertions, 23 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index b7cbb1e17c0..ced9a05ce59 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -1122,7 +1122,7 @@ pub struct MutTy {
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub struct MethodSig {
     pub unsafety: Unsafety,
-    pub constness: Constness,
+    pub constness: Spanned<Constness>,
     pub abi: Abi,
     pub decl: P<FnDecl>,
     pub generics: Generics,
@@ -1820,7 +1820,7 @@ pub enum ItemKind {
     /// A function declaration (`fn` or `pub fn`).
     ///
     /// E.g. `fn foo(bar: usize) -> usize { .. }`
-    Fn(P<FnDecl>, Unsafety, Constness, Abi, Generics, P<Block>),
+    Fn(P<FnDecl>, Unsafety, Spanned<Constness>, Abi, Generics, P<Block>),
     /// A module declaration (`mod` or `pub mod`).
     ///
     /// E.g. `mod foo;` or `mod foo { .. }`
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index 5d22930c4d5..2d9673574c3 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -12,7 +12,7 @@ use abi::Abi;
 use ast::{self, Ident, Generics, Expr, BlockCheckMode, UnOp, PatKind};
 use attr;
 use syntax_pos::{Span, DUMMY_SP, Pos};
-use codemap::{respan, Spanned};
+use codemap::{dummy_spanned, respan, Spanned};
 use ext::base::ExtCtxt;
 use parse::token::{self, keywords, InternedString};
 use ptr::P;
@@ -1016,7 +1016,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
                   Vec::new(),
                   ast::ItemKind::Fn(self.fn_decl(inputs, output),
                               ast::Unsafety::Normal,
-                              ast::Constness::NotConst,
+                              dummy_spanned(ast::Constness::NotConst),
                               Abi::Rust,
                               generics,
                               body))
diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index dc68e064634..9114c31d298 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -30,7 +30,7 @@ use ast::{NodeId, PatKind};
 use ast;
 use attr;
 use attr::AttrMetaMethods;
-use codemap::CodeMap;
+use codemap::{CodeMap, Spanned};
 use syntax_pos::Span;
 use errors::Handler;
 use visit::{self, FnKind, Visitor};
@@ -1046,7 +1046,7 @@ impl<'a> Visitor for PostExpansionVisitor<'a> {
                 _node_id: NodeId) {
         // check for const fn declarations
         match fn_kind {
-            FnKind::ItemFn(_, _, _, ast::Constness::Const, _, _) => {
+            FnKind::ItemFn(_, _, _, Spanned { node: ast::Constness::Const, .. }, _, _) => {
                 gate_feature_post!(&self, const_fn, span, "const fn is unstable");
             }
             _ => {
@@ -1078,7 +1078,7 @@ impl<'a> Visitor for PostExpansionVisitor<'a> {
                 if block.is_none() {
                     self.check_abi(sig.abi, ti.span);
                 }
-                if sig.constness == ast::Constness::Const {
+                if sig.constness.node == ast::Constness::Const {
                     gate_feature_post!(&self, const_fn, ti.span, "const fn is unstable");
                 }
             }
@@ -1105,7 +1105,7 @@ impl<'a> Visitor for PostExpansionVisitor<'a> {
                                   "associated constants are experimental")
             }
             ast::ImplItemKind::Method(ref sig, _) => {
-                if sig.constness == ast::Constness::Const {
+                if sig.constness.node == ast::Constness::Const {
                     gate_feature_post!(&self, const_fn, ii.span, "const fn is unstable");
                 }
             }
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index eb59a8e24d3..8272aa7b440 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -937,7 +937,10 @@ mod tests {
                                 variadic: false
                             }),
                                     ast::Unsafety::Normal,
-                                    ast::Constness::NotConst,
+                                    Spanned {
+                                        span: sp(0,2),
+                                        node: ast::Constness::NotConst,
+                                    },
                                     Abi::Rust,
                                     ast::Generics{ // no idea on either of these:
                                         lifetimes: Vec::new(),
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index d5d108084d6..92ec0fdb3de 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -39,7 +39,7 @@ use ast::{ViewPath, ViewPathGlob, ViewPathList, ViewPathSimple};
 use ast::{Visibility, WhereClause};
 use ast::{BinOpKind, UnOp};
 use ast;
-use codemap::{self, CodeMap, Spanned, spanned};
+use codemap::{self, CodeMap, Spanned, spanned, respan};
 use syntax_pos::{self, Span, BytePos, mk_sp};
 use errors::{self, DiagnosticBuilder};
 use ext::tt::macro_parser;
@@ -4770,7 +4770,7 @@ impl<'a> Parser<'a> {
     /// Parse an item-position function declaration.
     fn parse_item_fn(&mut self,
                      unsafety: Unsafety,
-                     constness: Constness,
+                     constness: Spanned<Constness>,
                      abi: abi::Abi)
                      -> PResult<'a, ItemInfo> {
         let (ident, mut generics) = self.parse_fn_header()?;
@@ -4796,18 +4796,21 @@ impl<'a> Parser<'a> {
     /// - `extern fn`
     /// - etc
     pub fn parse_fn_front_matter(&mut self)
-                                 -> PResult<'a, (ast::Constness, ast::Unsafety, abi::Abi)> {
+                                 -> PResult<'a, (Spanned<ast::Constness>,
+                                                ast::Unsafety,
+                                                abi::Abi)> {
         let is_const_fn = self.eat_keyword(keywords::Const);
+        let const_span = self.last_span;
         let unsafety = self.parse_unsafety()?;
         let (constness, unsafety, abi) = if is_const_fn {
-            (Constness::Const, unsafety, Abi::Rust)
+            (respan(const_span, Constness::Const), unsafety, Abi::Rust)
         } else {
             let abi = if self.eat_keyword(keywords::Extern) {
                 self.parse_opt_abi()?.unwrap_or(Abi::C)
             } else {
                 Abi::Rust
             };
-            (Constness::NotConst, unsafety, abi)
+            (respan(self.last_span, Constness::NotConst), unsafety, abi)
         };
         self.expect_keyword(keywords::Fn)?;
         Ok((constness, unsafety, abi))
@@ -5706,9 +5709,12 @@ impl<'a> Parser<'a> {
 
             if self.eat_keyword(keywords::Fn) {
                 // EXTERN FUNCTION ITEM
+                let fn_span = self.last_span;
                 let abi = opt_abi.unwrap_or(Abi::C);
                 let (ident, item_, extra_attrs) =
-                    self.parse_item_fn(Unsafety::Normal, Constness::NotConst, abi)?;
+                    self.parse_item_fn(Unsafety::Normal,
+                                       respan(fn_span, Constness::NotConst),
+                                       abi)?;
                 let last_span = self.last_span;
                 let item = self.mk_item(lo,
                                         last_span.hi,
@@ -5742,6 +5748,7 @@ impl<'a> Parser<'a> {
             return Ok(Some(item));
         }
         if self.eat_keyword(keywords::Const) {
+            let const_span = self.last_span;
             if self.check_keyword(keywords::Fn)
                 || (self.check_keyword(keywords::Unsafe)
                     && self.look_ahead(1, |t| t.is_keyword(keywords::Fn))) {
@@ -5753,7 +5760,9 @@ impl<'a> Parser<'a> {
                 };
                 self.bump();
                 let (ident, item_, extra_attrs) =
-                    self.parse_item_fn(unsafety, Constness::Const, Abi::Rust)?;
+                    self.parse_item_fn(unsafety,
+                                       respan(const_span, Constness::Const),
+                                       Abi::Rust)?;
                 let last_span = self.last_span;
                 let item = self.mk_item(lo,
                                         last_span.hi,
@@ -5817,8 +5826,11 @@ impl<'a> Parser<'a> {
         if self.check_keyword(keywords::Fn) {
             // FUNCTION ITEM
             self.bump();
+            let fn_span = self.last_span;
             let (ident, item_, extra_attrs) =
-                self.parse_item_fn(Unsafety::Normal, Constness::NotConst, Abi::Rust)?;
+                self.parse_item_fn(Unsafety::Normal,
+                                   respan(fn_span, Constness::NotConst),
+                                   Abi::Rust)?;
             let last_span = self.last_span;
             let item = self.mk_item(lo,
                                     last_span.hi,
@@ -5838,8 +5850,11 @@ impl<'a> Parser<'a> {
                 Abi::Rust
             };
             self.expect_keyword(keywords::Fn)?;
+            let fn_span = self.last_span;
             let (ident, item_, extra_attrs) =
-                self.parse_item_fn(Unsafety::Unsafe, Constness::NotConst, abi)?;
+                self.parse_item_fn(Unsafety::Unsafe,
+                                   respan(fn_span, Constness::NotConst),
+                                   abi)?;
             let last_span = self.last_span;
             let item = self.mk_item(lo,
                                     last_span.hi,
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 668bf89d3c6..6d59c6e8e48 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -1185,7 +1185,7 @@ impl<'a> State<'a> {
                 try!(self.print_fn(
                     decl,
                     unsafety,
-                    constness,
+                    constness.node,
                     abi,
                     Some(item.ident),
                     typarams,
@@ -1519,7 +1519,7 @@ impl<'a> State<'a> {
                             -> io::Result<()> {
         self.print_fn(&m.decl,
                       m.unsafety,
-                      m.constness,
+                      m.constness.node,
                       m.abi,
                       Some(ident),
                       &m.generics,
diff --git a/src/libsyntax/test.rs b/src/libsyntax/test.rs
index faf6a17a150..cbf9aa8c6c1 100644
--- a/src/libsyntax/test.rs
+++ b/src/libsyntax/test.rs
@@ -24,7 +24,7 @@ use attr;
 use syntax_pos::{self, DUMMY_SP, NO_EXPANSION, Span, FileMap, BytePos};
 use std::rc::Rc;
 
-use codemap::{self, CodeMap, ExpnInfo, NameAndSpan, MacroAttribute};
+use codemap::{self, CodeMap, ExpnInfo, NameAndSpan, MacroAttribute, dummy_spanned};
 use errors;
 use errors::snippet::{SnippetData};
 use config;
@@ -485,7 +485,7 @@ fn mk_main(cx: &mut TestCtxt) -> P<ast::Item> {
     let main_body = ecx.block(sp, vec![call_test_main]);
     let main = ast::ItemKind::Fn(ecx.fn_decl(vec![], main_ret_ty),
                            ast::Unsafety::Normal,
-                           ast::Constness::NotConst,
+                           dummy_spanned(ast::Constness::NotConst),
                            ::abi::Abi::Rust, ast::Generics::default(), main_body);
     let main = P(ast::Item {
         ident: token::str_to_ident("main"),
diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs
index 1124a5414b8..b2d47996659 100644
--- a/src/libsyntax/visit.rs
+++ b/src/libsyntax/visit.rs
@@ -31,7 +31,7 @@ use codemap::Spanned;
 #[derive(Copy, Clone, PartialEq, Eq)]
 pub enum FnKind<'a> {
     /// fn foo() or extern "Abi" fn foo()
-    ItemFn(Ident, &'a Generics, Unsafety, Constness, Abi, &'a Visibility),
+    ItemFn(Ident, &'a Generics, Unsafety, Spanned<Constness>, Abi, &'a Visibility),
 
     /// fn foo(&self)
     Method(Ident, &'a MethodSig, Option<&'a Visibility>),