Auto merge of #63779 - Centril:rollup-sx96dli, r=Centril

Rollup of 7 pull requests

Successful merges:

 - #63721 (Do not emit JSON dumps of diagnostic codes)
 - #63753 (Bump toml dependency.)
 - #63755 (Use dedicated type for spans in pre-expansion gating.)
 - #63759 (Allow 'default async fn' to parse.)
 - #63760 (Update books)
 - #63762 (`async_await` was stabilized in 1.39.0, not 1.38.0.)
 - #63766 (Remove some duplication when resolving constants)

Failed merges:

r? @ghost

Cargo.lock

@@ -185,7 +185,7 @@ dependencies = [
  "serde",
  "serde_json",
  "time",
- "toml 0.4.10",
+ "toml",
 ]
 
 [[package]]
@@ -202,7 +202,7 @@ name = "build-manifest"
 version = "0.1.0"
 dependencies = [
  "serde",
- "toml 0.4.10",
+ "toml",
 ]
 
 [[package]]
@@ -316,7 +316,7 @@ dependencies = [
  "tar",
  "tempfile",
  "termcolor",
- "toml 0.5.3",
+ "toml",
  "unicode-width",
  "url 2.1.0",
  "walkdir",
@@ -442,7 +442,7 @@ dependencies = [
  "semver",
  "serde",
  "smallvec",
- "toml 0.5.3",
+ "toml",
  "unicode-normalization",
  "url 2.1.0",
 ]
@@ -946,6 +946,7 @@ name = "error_index_generator"
 version = "0.0.0"
 dependencies = [
  "rustdoc",
+ "walkdir",
 ]
 
 [[package]]
@@ -1785,7 +1786,7 @@ dependencies = [
  "serde_json",
  "shlex",
  "tempfile",
- "toml 0.5.3",
+ "toml",
  "toml-query",
 ]
 
@@ -2760,7 +2761,7 @@ dependencies = [
  "tokio",
  "tokio-process",
  "tokio-timer",
- "toml 0.5.3",
+ "toml",
  "url 1.7.2",
  "walkdir",
 ]
@@ -3590,7 +3591,7 @@ dependencies = [
  "serde_json",
  "structopt",
  "term 0.6.0",
- "toml 0.5.3",
+ "toml",
  "unicode-segmentation",
  "unicode-width",
  "unicode_categories",
@@ -4382,15 +4383,6 @@ dependencies = [
  "tokio-reactor",
 ]
 
-[[package]]
-name = "toml"
-version = "0.4.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "758664fc71a3a69038656bee8b6be6477d2a6c315a6b81f7081f591bffa4111f"
-dependencies = [
- "serde",
-]
-
 [[package]]
 name = "toml"
 version = "0.5.3"
@@ -4411,7 +4403,7 @@ dependencies = [
  "is-match",
  "lazy_static 1.3.0",
  "regex",
- "toml 0.5.3",
+ "toml",
  "toml-query_derive",
 ]
 

src/bootstrap/Cargo.toml

@@ -44,7 +44,7 @@ cc = "1.0.35"
 libc = "0.2"
 serde = { version = "1.0.8", features = ["derive"] }
 serde_json = "1.0.2"
-toml = "0.4"
+toml = "0.5"
 lazy_static = "1.3.0"
 time = "0.1"
 petgraph = "0.4.13"

src/bootstrap/doc.rs

@@ -825,8 +825,7 @@ impl Step for ErrorIndex {
         index.arg(crate::channel::CFG_RELEASE_NUM);
 
         // FIXME: shouldn't have to pass this env var
-        index.env("CFG_BUILD", &builder.config.build)
-             .env("RUSTC_ERROR_METADATA_DST", builder.extended_error_dir());
+        index.env("CFG_BUILD", &builder.config.build);
 
         builder.run(&mut index);
     }

src/bootstrap/test.rs

@@ -1535,8 +1535,7 @@ impl Step for ErrorIndex {
         );
         tool.arg("markdown")
             .arg(&output)
-            .env("CFG_BUILD", &builder.config.build)
-            .env("RUSTC_ERROR_METADATA_DST", builder.extended_error_dir());
+            .env("CFG_BUILD", &builder.config.build);
 
         builder.info(&format!("Testing error-index stage{}", compiler.stage));
         let _time = util::timeit(&builder);

src/librustc/ty/relate.rs

@@ -8,7 +8,7 @@ use crate::hir::def_id::DefId;
 use crate::ty::subst::{Kind, UnpackedKind, SubstsRef};
 use crate::ty::{self, Ty, TyCtxt, TypeFoldable};
 use crate::ty::error::{ExpectedFound, TypeError};
-use crate::mir::interpret::{ConstValue, Scalar, GlobalId};
+use crate::mir::interpret::{ConstValue, Scalar};
 use std::rc::Rc;
 use std::iter;
 use rustc_target::spec::abi;
@@ -551,26 +551,8 @@ pub fn super_relate_consts<R: TypeRelation<'tcx>>(
     let tcx = relation.tcx();
 
     let eagerly_eval = |x: &'tcx ty::Const<'tcx>| {
-        if let ConstValue::Unevaluated(def_id, substs) = x.val {
-            // FIXME(eddyb) get the right param_env.
-            let param_env = ty::ParamEnv::empty();
-            if !substs.has_local_value() {
-                let instance = ty::Instance::resolve(
-                    tcx.global_tcx(),
-                    param_env,
-                    def_id,
-                    substs,
-                );
-                if let Some(instance) = instance {
-                    let cid = GlobalId {
-                        instance,
-                        promoted: None,
-                    };
-                    if let Ok(ct) = tcx.const_eval(param_env.and(cid)) {
-                        return ct.val;
-                    }
-                }
-            }
+        if !x.val.has_local_value() {
+            return x.eval(tcx, relation.param_env()).val;
         }
         x.val
     };

src/librustc/ty/sty.rs

@@ -2299,23 +2299,33 @@ impl<'tcx> Const<'tcx> {
         assert_eq!(self.ty, ty);
         // if `ty` does not depend on generic parameters, use an empty param_env
         let size = tcx.layout_of(param_env.with_reveal_all().and(ty)).ok()?.size;
+        self.eval(tcx, param_env).val.try_to_bits(size)
+    }
+
+    #[inline]
+    pub fn eval(
+        &self,
+        tcx: TyCtxt<'tcx>,
+        param_env: ParamEnv<'tcx>,
+    ) -> &Const<'tcx> {
+        // FIXME(const_generics): this doesn't work right now,
+        // because it tries to relate an `Infer` to a `Param`.
         match self.val {
-            // FIXME(const_generics): this doesn't work right now,
-            // because it tries to relate an `Infer` to a `Param`.
             ConstValue::Unevaluated(did, substs) => {
                 // if `substs` has no unresolved components, use and empty param_env
                 let (param_env, substs) = param_env.with_reveal_all().and(substs).into_parts();
                 // try to resolve e.g. associated constants to their definition on an impl
-                let instance = ty::Instance::resolve(tcx, param_env, did, substs)?;
+                let instance = match ty::Instance::resolve(tcx, param_env, did, substs) {
+                    Some(instance) => instance,
+                    None => return self,
+                };
                 let gid = GlobalId {
                     instance,
                     promoted: None,
                 };
-                let evaluated = tcx.const_eval(param_env.and(gid)).ok()?;
-                evaluated.val.try_to_bits(size)
+                tcx.const_eval(param_env.and(gid)).unwrap_or(self)
             },
-            // otherwise just extract a `ConstValue`'s bits if possible
-            _ => self.val.try_to_bits(size),
+            _ => self,
         }
     }
 

src/libsyntax/diagnostics/plugin.rs

@@ -1,5 +1,4 @@
 use std::collections::BTreeMap;
-use std::env;
 
 use crate::ast::{self, Ident, Name};
 use crate::source_map;
@@ -12,8 +11,6 @@ use crate::tokenstream::{TokenTree};
 use smallvec::smallvec;
 use syntax_pos::Span;
 
-use crate::diagnostics::metadata::output_metadata;
-
 pub use errors::*;
 
 // Maximum width of any line in an extended error description (inclusive).
@@ -127,36 +124,13 @@ pub fn expand_build_diagnostic_array<'cx>(ecx: &'cx mut ExtCtxt<'_>,
                                           token_tree: &[TokenTree])
                                           -> Box<dyn MacResult+'cx> {
     assert_eq!(token_tree.len(), 3);
-    let (crate_name, ident) = match (&token_tree[0], &token_tree[2]) {
-        (
-            // Crate name.
-            &TokenTree::Token(Token { kind: token::Ident(crate_name, _), .. }),
-            // DIAGNOSTICS ident.
-            &TokenTree::Token(Token { kind: token::Ident(name, _), span })
-        ) => (crate_name, Ident::new(name, span)),
+    let ident = match &token_tree[2] {
+        // DIAGNOSTICS ident.
+        &TokenTree::Token(Token { kind: token::Ident(name, _), span })
+        => Ident::new(name, span),
         _ => unreachable!()
     };
 
-    // Output error metadata to `tmp/extended-errors/<target arch>/<crate name>.json`
-    if let Ok(target_triple) = env::var("CFG_COMPILER_HOST_TRIPLE") {
-        ecx.parse_sess.registered_diagnostics.with_lock(|diagnostics| {
-            if let Err(e) = output_metadata(ecx,
-                                            &target_triple,
-                                            &crate_name.as_str(),
-                                            diagnostics) {
-                ecx.span_bug(span, &format!(
-                    "error writing metadata for triple `{}` and crate `{}`, error: {}, \
-                     cause: {:?}",
-                    target_triple, crate_name, e.description(), e.source()
-                ));
-            }
-        });
-    } else {
-        ecx.span_err(span, &format!(
-            "failed to write metadata for crate `{}` because $CFG_COMPILER_HOST_TRIPLE is not set",
-            crate_name));
-    }
-
     // Construct the output expression.
     let (count, expr) =
         ecx.parse_sess.registered_diagnostics.with_lock(|diagnostics| {