auto merge of #15319 : alexcrichton/rust/no-crate-id, r=brson

This is an implementation of [RFC 35](https://github.com/rust-lang/rfcs/blob/master/active/0035-remove-crate-id.md).

The summary for this PR is the same as that of the RFC, with one addendum:


* Removes the `#[crate_id]` attribute and knowledge of versions from rustc.
* Added a `#[crate_name]` attribute similar to the old `#[crate_id]` attribute
* Output filenames no longer have versions or hashes
* Symbols no longer have versions (they still have hashes)
* A new flag, `--extern`, is used to override searching for external crates
* A new flag, `-C metadata=foo`, used when hashing symbols
* [added] An old flag, `--crate-name`, was re purposed to specify the crate name from the command line.

I tried to maintain backwards compatibility wherever possible (with warnings being printed). If I missed anywhere, however, please let me know!

[breaking-change]

Closes #14468
Closes #14469
Closes #14470
Closes #14471

2 files changed, 6 insertions, 7 deletions

diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index cf69277594f..673ae31ef77 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -452,7 +452,7 @@ impl<'a> ExtCtxt<'a> {
     pub fn mod_pop(&mut self) { self.mod_path.pop().unwrap(); }
     pub fn mod_path(&self) -> Vec<ast::Ident> {
         let mut v = Vec::new();
-        v.push(token::str_to_ident(self.ecfg.crate_id.name.as_slice()));
+        v.push(token::str_to_ident(self.ecfg.crate_name.as_slice()));
         v.extend(self.mod_path.iter().map(|a| *a));
         return v;
     }
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index b30b62c8901..752b3a09e65 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -19,7 +19,6 @@ use attr;
 use attr::AttrMetaMethods;
 use codemap;
 use codemap::{Span, Spanned, ExpnInfo, NameAndSpan, MacroBang, MacroAttribute};
-use crateid::CrateId;
 use ext::base::*;
 use fold;
 use fold::*;
@@ -985,7 +984,7 @@ fn new_span(cx: &ExtCtxt, sp: Span) -> Span {
 
 pub struct ExpansionConfig {
     pub deriving_hash_type_parameter: bool,
-    pub crate_id: CrateId,
+    pub crate_name: String,
 }
 
 pub struct ExportedMacros {
@@ -1184,7 +1183,7 @@ mod test {
         // should fail:
         let cfg = ::syntax::ext::expand::ExpansionConfig {
             deriving_hash_type_parameter: false,
-            crate_id: from_str("test").unwrap(),
+            crate_name: "test".to_str(),
         };
         expand_crate(&sess,cfg,vec!(),vec!(),crate_ast);
     }
@@ -1201,7 +1200,7 @@ mod test {
             Vec::new(), &sess);
         let cfg = ::syntax::ext::expand::ExpansionConfig {
             deriving_hash_type_parameter: false,
-            crate_id: from_str("test").unwrap(),
+            crate_name: "test".to_str(),
         };
         expand_crate(&sess,cfg,vec!(),vec!(),crate_ast);
     }
@@ -1217,7 +1216,7 @@ mod test {
             Vec::new(), &sess);
         let cfg = ::syntax::ext::expand::ExpansionConfig {
             deriving_hash_type_parameter: false,
-            crate_id: from_str("test").unwrap(),
+            crate_name: "test".to_str(),
         };
         expand_crate(&sess, cfg, vec!(), vec!(), crate_ast);
     }
@@ -1254,7 +1253,7 @@ mod test {
         // the cfg argument actually does matter, here...
         let cfg = ::syntax::ext::expand::ExpansionConfig {
             deriving_hash_type_parameter: false,
-            crate_id: from_str("test").unwrap(),
+            crate_name: "test".to_str(),
         };
         expand_crate(&ps,cfg,vec!(),vec!(),crate_ast)
     }