Fix for #31267 and additional zero-width constant bug

CONTRIBUTING.md

@@ -6,6 +6,7 @@ links to the major sections:
 
 * [Feature Requests](#feature-requests)
 * [Bug Reports](#bug-reports)
+* [The Build System](#the-build-system)
 * [Pull Requests](#pull-requests)
 * [Writing Documentation](#writing-documentation)
 * [Issue Triage](#issue-triage)
@@ -77,6 +78,66 @@ to do this is to invoke `rustc` like this:
 $ RUST_BACKTRACE=1 rustc ...
 ```
 
+## The Build System
+
+Rust's build system allows you to bootstrap the compiler, run tests &
+benchmarks, generate documentation, install a fresh build of Rust, and more.
+It's your best friend when working on Rust, allowing you to compile & test
+your contributions before submission.
+
+All the configuration for the build system lives in [the `mk` directory][mkdir]
+in the project root. It can be hard to follow in places, as it uses some
+advanced Make features which make for some challenging reading. If you have
+questions on the build system internals, try asking in
+[`#rust-internals`][pound-rust-internals].
+
+[mkdir]: https://github.com/rust-lang/rust/tree/master/mk/
+
+### Configuration
+
+Before you can start building the compiler you need to configure the build for
+your system. In most cases, that will just mean using the defaults provided
+for Rust. Configuring involves invoking the `configure` script in the project
+root.
+
+```
+./configure
+```
+
+There are large number of options accepted by this script to alter the
+configuration used later in the build process. Some options to note:
+
+- `--enable-debug` - Build a debug version of the compiler (disables optimizations)
+- `--enable-optimize` - Enable optimizations (can be used with `--enable-debug`
+    to make a debug build with optimizations)
+- `--disable-valgrind-rpass` - Don't run tests with valgrind
+- `--enable-clang` - Prefer clang to gcc for building dependencies (e.g., LLVM)
+- `--enable-ccache` - Invoke clang/gcc with ccache to re-use object files between builds
+- `--enable-compiler-docs` - Build compiler documentation
+
+To see a full list of options, run `./configure --help`.
+
+### Useful Targets
+
+Some common make targets are:
+
+- `make rustc-stage1` - build up to (and including) the first stage. For most
+  cases we don't need to build the stage2 compiler, so we can save time by not
+  building it. The stage1 compiler is a fully functioning compiler and
+  (probably) will be enough to determine if your change works as expected.
+- `make check` - build the full compiler & run all tests (takes a while). This
+  is what gets run by the continuous integration system against your pull
+  request. You should run this before submitting to make sure your tests pass
+  & everything builds in the correct manner.
+- `make check-stage1-std NO_REBUILD=1` - test the standard library without
+  rebuilding the entire compiler
+- `make check TESTNAME=<path-to-test-file>.rs` - Run a single test file
+- `make check-stage1-rpass TESTNAME=<path-to-test-file>.rs` - Run a single
+  rpass test with the stage1 compiler (this will be quicker than running the
+  command above as we only build the stage1 compiler, not the entire thing).
+  You can also leave off the `-rpass` to run all stage1 test types.
+- `make check-stage1-coretest` - Run stage1 tests in `libcore`.
+
 ## Pull Requests
 
 Pull requests are the primary mechanism we use to change Rust. GitHub itself

configure

@@ -1409,6 +1409,7 @@ do
     make_dir $h/test/debuginfo-gdb
     make_dir $h/test/debuginfo-lldb
     make_dir $h/test/codegen
+    make_dir $h/test/codegen-units
     make_dir $h/test/rustdoc
 done
 

mk/cfg/armv7-unknown-linux-gnueabihf.mk

@@ -0,0 +1,26 @@
+# armv7-unknown-linux-gnueabihf configuration
+CROSS_PREFIX_armv7-unknown-linux-gnueabihf=armv7-unknown-linux-gnueabihf-
+CC_armv7-unknown-linux-gnueabihf=gcc
+CXX_armv7-unknown-linux-gnueabihf=g++
+CPP_armv7-unknown-linux-gnueabihf=gcc -E
+AR_armv7-unknown-linux-gnueabihf=ar
+CFG_LIB_NAME_armv7-unknown-linux-gnueabihf=lib$(1).so
+CFG_STATIC_LIB_NAME_armv7-unknown-linux-gnueabihf=lib$(1).a
+CFG_LIB_GLOB_armv7-unknown-linux-gnueabihf=lib$(1)-*.so
+CFG_LIB_DSYM_GLOB_armv7-unknown-linux-gnueabihf=lib$(1)-*.dylib.dSYM
+CFG_JEMALLOC_CFLAGS_armv7-unknown-linux-gnueabihf := -D__arm__ $(CFLAGS)
+CFG_GCCISH_CFLAGS_armv7-unknown-linux-gnueabihf := -Wall -g -fPIC -D__arm__ $(CFLAGS)
+CFG_GCCISH_CXXFLAGS_armv7-unknown-linux-gnueabihf := -fno-rtti $(CXXFLAGS)
+CFG_GCCISH_LINK_FLAGS_armv7-unknown-linux-gnueabihf := -shared -fPIC -g
+CFG_GCCISH_DEF_FLAG_armv7-unknown-linux-gnueabihf := -Wl,--export-dynamic,--dynamic-list=
+CFG_LLC_FLAGS_armv7-unknown-linux-gnueabihf :=
+CFG_INSTALL_NAME_ar,-unknown-linux-gnueabihf =
+CFG_EXE_SUFFIX_armv7-unknown-linux-gnueabihf :=
+CFG_WINDOWSY_armv7-unknown-linux-gnueabihf :=
+CFG_UNIXY_armv7-unknown-linux-gnueabihf := 1
+CFG_LDPATH_armv7-unknown-linux-gnueabihf :=
+CFG_RUN_armv7-unknown-linux-gnueabihf=$(2)
+CFG_RUN_TARG_armv7-unknown-linux-gnueabihf=$(call CFG_RUN_armv7-unknown-linux-gnueabihf,,$(2))
+RUSTC_FLAGS_armv7-unknown-linux-gnueabihf := -C target-feature=+v7,+vfp2,+neon
+RUSTC_CROSS_FLAGS_armv7-unknown-linux-gnueabihf :=
+CFG_GNU_TRIPLE_armv7-unknown-linux-gnueabihf := armv7-unknown-linux-gnueabihf

mk/cfg/armv7s-apple-ios.mk

@@ -14,8 +14,8 @@ CFG_LIB_GLOB_armv7s-apple-ios = lib$(1)-*.a
 CFG_INSTALL_ONLY_RLIB_armv7s-apple-ios = 1
 CFG_STATIC_LIB_NAME_armv7s-apple-ios=lib$(1).a
 CFG_LIB_DSYM_GLOB_armv7s-apple-ios = lib$(1)-*.a.dSYM
-CFG_JEMALLOC_CFLAGS_armv7s-apple-ios := -arch armv7s -mfpu=vfp4 $(CFG_IOS_SDK_FLAGS_armv7s-apple-ios)
-CFG_GCCISH_CFLAGS_armv7s-apple-ios := -Wall -Werror -g -fPIC $(CFG_IOS_SDK_FLAGS_armv7s-apple-ios) -mfpu=vfp4 -arch armv7s
+CFG_JEMALLOC_CFLAGS_armv7s-apple-ios := -arch armv7s $(CFG_IOS_SDK_FLAGS_armv7s-apple-ios)
+CFG_GCCISH_CFLAGS_armv7s-apple-ios := -Wall -Werror -g -fPIC $(CFG_IOS_SDK_FLAGS_armv7s-apple-ios) -arch armv7s
 CFG_GCCISH_CXXFLAGS_armv7s-apple-ios := -fno-rtti $(CFG_IOS_SDK_FLAGS_armv7s-apple-ios) -I$(CFG_IOS_SDK_armv7s-apple-ios)/usr/include/c++/4.2.1
 CFG_GCCISH_LINK_FLAGS_armv7s-apple-ios := -lpthread -syslibroot $(CFG_IOS_SDK_armv7s-apple-ios) -Wl,-no_compact_unwind
 CFG_GCCISH_DEF_FLAG_armv7s-apple-ios := -Wl,-exported_symbols_list,

mk/cfg/powerpc64-unknown-linux-gnu.mk

@@ -1,5 +1,5 @@
 # powerpc64-unknown-linux-gnu configuration
-CROSS_PREFIX_powerpc64-unknown-linux-gnu=powerpc64-linux-gnu-
+CROSS_PREFIX_powerpc64-unknown-linux-gnu=powerpc-linux-gnu-
 CC_powerpc64-unknown-linux-gnu=$(CC)
 CXX_powerpc64-unknown-linux-gnu=$(CXX)
 CPP_powerpc64-unknown-linux-gnu=$(CPP)

mk/tests.mk

@@ -310,6 +310,7 @@ check-stage$(1)-T-$(2)-H-$(3)-exec: \
 	check-stage$(1)-T-$(2)-H-$(3)-debuginfo-gdb-exec \
 	check-stage$(1)-T-$(2)-H-$(3)-debuginfo-lldb-exec \
 	check-stage$(1)-T-$(2)-H-$(3)-codegen-exec \
+	check-stage$(1)-T-$(2)-H-$(3)-codegen-units-exec \
 	check-stage$(1)-T-$(2)-H-$(3)-doc-exec \
 	check-stage$(1)-T-$(2)-H-$(3)-pretty-exec
 
@@ -473,6 +474,7 @@ DEBUGINFO_GDB_RS := $(wildcard $(S)src/test/debuginfo/*.rs)
 DEBUGINFO_LLDB_RS := $(wildcard $(S)src/test/debuginfo/*.rs)
 CODEGEN_RS := $(wildcard $(S)src/test/codegen/*.rs)
 CODEGEN_CC := $(wildcard $(S)src/test/codegen/*.cc)
+CODEGEN_UNITS_RS := $(wildcard $(S)src/test/codegen-units/*.rs)
 RUSTDOCCK_RS := $(wildcard $(S)src/test/rustdoc/*.rs)
 
 RPASS_TESTS := $(RPASS_RS)
@@ -488,6 +490,7 @@ PRETTY_TESTS := $(PRETTY_RS)
 DEBUGINFO_GDB_TESTS := $(DEBUGINFO_GDB_RS)
 DEBUGINFO_LLDB_TESTS := $(DEBUGINFO_LLDB_RS)
 CODEGEN_TESTS := $(CODEGEN_RS) $(CODEGEN_CC)
+CODEGEN_UNITS_TESTS := $(CODEGEN_UNITS_RS)
 RUSTDOCCK_TESTS := $(RUSTDOCCK_RS)
 
 CTEST_SRC_BASE_rpass = run-pass
@@ -550,6 +553,11 @@ CTEST_BUILD_BASE_codegen = codegen
 CTEST_MODE_codegen = codegen
 CTEST_RUNTOOL_codegen = $(CTEST_RUNTOOL)
 
+CTEST_SRC_BASE_codegen-units = codegen-units
+CTEST_BUILD_BASE_codegen-units = codegen-units
+CTEST_MODE_codegen-units = codegen-units
+CTEST_RUNTOOL_codegen-units = $(CTEST_RUNTOOL)
+
 CTEST_SRC_BASE_rustdocck = rustdoc
 CTEST_BUILD_BASE_rustdocck = rustdoc
 CTEST_MODE_rustdocck = rustdoc
@@ -673,6 +681,7 @@ CTEST_DEPS_debuginfo-lldb_$(1)-T-$(2)-H-$(3) = $$(DEBUGINFO_LLDB_TESTS) \
                                                $(S)src/etc/lldb_batchmode.py \
                                                $(S)src/etc/lldb_rust_formatters.py
 CTEST_DEPS_codegen_$(1)-T-$(2)-H-$(3) = $$(CODEGEN_TESTS)
+CTEST_DEPS_codegen-units_$(1)-T-$(2)-H-$(3) = $$(CODEGEN_UNITS_TESTS)
 CTEST_DEPS_rustdocck_$(1)-T-$(2)-H-$(3) = $$(RUSTDOCCK_TESTS) \
         $$(HBIN$(1)_H_$(3))/rustdoc$$(X_$(3)) \
 	$(S)src/etc/htmldocck.py
@@ -739,7 +748,7 @@ endif
 endef
 
 CTEST_NAMES = rpass rpass-valgrind rpass-full rfail-full cfail-full rfail cfail pfail \
-	bench debuginfo-gdb debuginfo-lldb codegen rustdocck
+	bench debuginfo-gdb debuginfo-lldb codegen codegen-units rustdocck
 
 $(foreach host,$(CFG_HOST), \
  $(eval $(foreach target,$(CFG_TARGET), \
@@ -917,6 +926,7 @@ TEST_GROUPS = \
 	debuginfo-gdb \
 	debuginfo-lldb \
 	codegen \
+	codegen-units \
 	doc \
 	$(foreach docname,$(DOC_NAMES),doc-$(docname)) \
 	pretty \

src/compiletest/common.rs

@@ -25,6 +25,7 @@ pub enum Mode {
     DebugInfoLldb,
     Codegen,
     Rustdoc,
+    CodegenUnits
 }
 
 impl FromStr for Mode {
@@ -41,6 +42,7 @@ impl FromStr for Mode {
           "debuginfo-gdb" => Ok(DebugInfoGdb),
           "codegen" => Ok(Codegen),
           "rustdoc" => Ok(Rustdoc),
+          "codegen-units" => Ok(CodegenUnits),
           _ => Err(()),
         }
     }
@@ -59,6 +61,7 @@ impl fmt::Display for Mode {
             DebugInfoLldb => "debuginfo-lldb",
             Codegen => "codegen",
             Rustdoc => "rustdoc",
+            CodegenUnits => "codegen-units",
         }, f)
     }
 }

src/compiletest/runtest.rs

@@ -10,14 +10,15 @@
 
 use common::Config;
 use common::{CompileFail, ParseFail, Pretty, RunFail, RunPass, RunPassValgrind};
-use common::{Codegen, DebugInfoLldb, DebugInfoGdb, Rustdoc};
+use common::{Codegen, DebugInfoLldb, DebugInfoGdb, Rustdoc, CodegenUnits};
 use errors;
 use header::TestProps;
 use header;
 use procsrv;
 use util::logv;
 
 use std::env;
+use std::collections::HashSet;
 use std::fmt;
 use std::fs::{self, File};
 use std::io::BufReader;
@@ -56,6 +57,7 @@ pub fn run(config: Config, testfile: &Path) {
         DebugInfoLldb => run_debuginfo_lldb_test(&config, &props, &testfile),
         Codegen => run_codegen_test(&config, &props, &testfile),
         Rustdoc => run_rustdoc_test(&config, &props, &testfile),
+        CodegenUnits => run_codegen_units_test(&config, &props, &testfile),
     }
 }
 
@@ -1747,3 +1749,44 @@ fn run_rustdoc_test(config: &Config, props: &TestProps, testfile: &Path) {
         fatal_proc_rec("htmldocck failed!", &res);
     }
 }
+
+fn run_codegen_units_test(config: &Config, props: &TestProps, testfile: &Path) {
+    let proc_res = compile_test(config, props, testfile);
+
+    if !proc_res.status.success() {
+        fatal_proc_rec("compilation failed!", &proc_res);
+    }
+
+    check_no_compiler_crash(&proc_res);
+
+    let prefix = "TRANS_ITEM ";
+
+    let actual: HashSet<String> = proc_res
+        .stdout
+        .lines()
+        .filter(|line| line.starts_with(prefix))
+        .map(|s| (&s[prefix.len()..]).to_string())
+        .collect();
+
+    let expected: HashSet<String> = errors::load_errors(testfile)
+        .iter()
+        .map(|e| e.msg.trim().to_string())
+        .collect();
+
+    if actual != expected {
+        let mut missing: Vec<_> = expected.difference(&actual).collect();
+        missing.sort();
+
+        let mut too_much: Vec<_> = actual.difference(&expected).collect();
+        too_much.sort();
+
+        println!("Expected and actual sets of codegen-items differ.\n\
+                  These items should have been contained but were not:\n\n\
+                  {}\n\n\
+                  These items were contained but should not have been:\n\n\
+                  {}\n\n",
+            missing.iter().fold("".to_string(), |s1, s2| s1 + "\n" + s2),
+            too_much.iter().fold("".to_string(), |s1, s2| s1 + "\n" + s2));
+        panic!();
+    }
+}

src/doc/book/crates-and-modules.md

@@ -567,10 +567,11 @@ to it as "sayings". Similarly, the first `use` statement pulls in the
 `ja_greetings` as opposed to simply `greetings`. This can help to avoid
 ambiguity when importing similarly-named items from different places.
 
-The second `use` statement uses a star glob to bring in _all_ symbols from the
-`sayings::japanese::farewells` module. As you can see we can later refer to
+The second `use` statement uses a star glob to bring in all public symbols from
+the `sayings::japanese::farewells` module. As you can see we can later refer to
 the Japanese `goodbye` function with no module qualifiers. This kind of glob
-should be used sparingly.
+should be used sparingly. It’s worth noting that it only imports the public
+symbols, even if the code doing the globbing is in the same module.
 
 The third `use` statement bears more explanation. It's using "brace expansion"
 globbing to compress three `use` statements into one (this sort of syntax

src/doc/book/macros.md

@@ -478,9 +478,9 @@ which syntactic form it matches.
 
 There are additional rules regarding the next token after a metavariable:
 
-* `expr` variables may only be followed by one of: `=> , ;`
-* `ty` and `path` variables may only be followed by one of: `=> , : = > as`
-* `pat` variables may only be followed by one of: `=> , = if in`
+* `expr` and `stmt` variables may only be followed by one of: `=> , ;`
+* `ty` and `path` variables may only be followed by one of: `=> , = | ; : > [ { as where`
+* `pat` variables may only be followed by one of: `=> , = | if in`
 * Other variables may be followed by any token.
 
 These rules provide some flexibility for Rust’s syntax to evolve without

src/doc/book/syntax-index.md

@@ -2,7 +2,7 @@
 
 ## Keywords
 
-* `as`: primitive casting.  See [Casting Between Types (`as`)].
+* `as`: primitive casting, or disambiguating the specific trait containing an item.  See [Casting Between Types (`as`)], [Universal Function Call Syntax (Angle-bracket Form)], [Associated Types].
 * `break`: break out of loop.  See [Loops (Ending Iteration Early)].
 * `const`: constant items and constant raw pointers.  See [`const` and `static`], [Raw Pointers].
 * `continue`: continue to next loop iteration.  See [Loops (Ending Iteration Early)].
@@ -115,8 +115,11 @@
 * `::path`: path relative to the crate root (*i.e.* an explicitly absolute path).  See [Crates and Modules (Re-exporting with `pub use`)].
 * `self::path`: path relative to the current module (*i.e.* an explicitly relative path).  See [Crates and Modules (Re-exporting with `pub use`)].
 * `super::path`: path relative to the parent of the current module.  See [Crates and Modules (Re-exporting with `pub use`)].
-* `type::ident`: associated constants, functions, and types.  See [Associated Types].
+* `type::ident`, `<type as trait>::ident`: associated constants, functions, and types.  See [Associated Types].
 * `<type>::…`: associated item for a type which cannot be directly named (*e.g.* `<&T>::…`, `<[T]>::…`, *etc.*).  See [Associated Types].
+* `trait::method(…)`: disambiguating a method call by naming the trait which defines it. See [Universal Function Call Syntax].
+* `type::method(…)`: disambiguating a method call by naming the type for which it's defined. See [Universal Function Call Syntax].
+* `<type as trait>::method(…)`: disambiguating a method call by naming the trait _and_ type. See [Universal Function Call Syntax (Angle-bracket Form)].
 
 <!-- Generics -->
 
@@ -132,7 +135,8 @@
 <!-- Constraints -->
 
 * `T: U`: generic parameter `T` constrained to types that implement `U`.  See [Traits].
-* `T: 'a`: generic type `T` must outlive lifetime `'a`.
+* `T: 'a`: generic type `T` must outlive lifetime `'a`. When we say that a type 'outlives' the lifetime, we mean that it cannot transitively contain any references with lifetimes shorter than `'a`.
+* `T : 'static`: The generic type `T` contains no borrowed references other than `'static` ones.
 * `'b: 'a`: generic lifetime `'b` must outlive lifetime `'a`.
 * `T: ?Sized`: allow generic type parameter to be a dynamically-sized type.  See [Unsized Types (`?Sized`)].
 * `'a + trait`, `trait + trait`: compound type constraint.  See [Traits (Multiple Trait Bounds)].
@@ -234,6 +238,8 @@
 [Traits (`where` clause)]: traits.html#where-clause
 [Traits (Multiple Trait Bounds)]: traits.html#multiple-trait-bounds
 [Traits]: traits.html
+[Universal Function Call Syntax]: ufcs.html
+[Universal Function Call Syntax (Angle-bracket Form)]: ufcs.html#angle-bracket-form
 [Unsafe]: unsafe.html
 [Unsized Types (`?Sized`)]: unsized-types.html#sized
 [Variable Bindings]: variable-bindings.html

src/doc/reference.md

@@ -104,7 +104,7 @@ comments (`/** ... */`), are interpreted as a special syntax for `doc`
 `#[doc="..."]` around the body of the comment, i.e., `/// Foo` turns into
 `#[doc="Foo"]`.
 
-Line comments beginning with `//!` and block comments `/*! ... !*/` are
+Line comments beginning with `//!` and block comments `/*! ... */` are
 doc comments that apply to the parent of the comment, rather than the item
 that follows.  That is, they are equivalent to writing `#![doc="..."]` around
 the body of the comment. `//!` comments are usually used to document
@@ -2095,7 +2095,7 @@ along with their default settings.  [Compiler
 plugins](book/compiler-plugins.html#lint-plugins) can provide additional lint checks.
 
 ```{.ignore}
-mod m1 {
+pub mod m1 {
     // Missing documentation is ignored here
     #[allow(missing_docs)]
     pub fn undocumented_one() -> i32 { 1 }
@@ -2115,9 +2115,9 @@ check on and off:
 
 ```{.ignore}
 #[warn(missing_docs)]
-mod m2{
+pub mod m2{
     #[allow(missing_docs)]
-    mod nested {
+    pub mod nested {
         // Missing documentation is ignored here
         pub fn undocumented_one() -> i32 { 1 }
 
@@ -2137,7 +2137,7 @@ that lint check:
 
 ```{.ignore}
 #[forbid(missing_docs)]
-mod m3 {
+pub mod m3 {
     // Attempting to toggle warning signals an error here
     #[allow(missing_docs)]
     /// Returns 2.