Auto merge of #48127 - kennytm:debug-48116, r=<try>

[WIP] Debug #48116.

1. When the invalid condition is hit, write out the relevant variables too
2. In compile-fail/parse-fail tests, check for ICE first, so the invalid error patterns won't mask our ICE output.

r? @alexcrichton
cc #48116, cc @eddyb

.travis.yml

@@ -13,10 +13,10 @@ matrix:
   include:
     # Images used in testing PR and try-build should be run first.
     - env: IMAGE=x86_64-gnu-llvm-3.9 RUST_BACKTRACE=1
-      if: type = pull_request OR branch = auto
+      if: branch = auto
 
     - env: IMAGE=dist-x86_64-linux DEPLOY=1
-      if: branch = try OR branch = auto
+      if: branch = auto
 
     # "alternate" deployments, these are "nightlies" but have LLVM assertions
     # turned on, they're deployed to a different location primarily for
@@ -57,7 +57,7 @@ matrix:
         NO_DEBUG_ASSERTIONS=1
       os: osx
       osx_image: xcode8.3
-      if: branch = auto
+      #if: branch = auto
 
     - env: >
         RUST_CHECK_TARGET=check

src/bootstrap/mk/Makefile.in

@@ -49,7 +49,7 @@ book:
 standalone-docs:
 	$(Q)$(BOOTSTRAP) doc src/doc $(BOOTSTRAP_ARGS)
 check:
-	$(Q)$(BOOTSTRAP) test $(BOOTSTRAP_ARGS)
+	$(Q)$(BOOTSTRAP) test $(BOOTSTRAP_ARGS) src/test/compile-fail --test-args single-segment
 check-aux:
 	$(Q)$(BOOTSTRAP) test \
 		src/tools/cargo \

src/ci/run.sh

@@ -105,7 +105,7 @@ else
     return $retval
   }
 
-  do_make tidy
-  do_make all
+  #do_make tidy
+  #do_make all
   do_make "$RUST_CHECK_TARGET"
 fi

src/librustc_resolve/resolve_imports.rs

@@ -499,6 +499,11 @@ impl<'a, 'b:'a> ImportResolver<'a, 'b> {
                 // resolution for it so that later resolve stages won't complain.
                 self.import_dummy_binding(import);
                 if !seen_spans.contains(&span) {
+                    info!(
+                        "preparing to import_path_to_string(import={:?}, span={:?})",
+                        import,
+                        span
+                    );
                     let path = import_path_to_string(&import.module_path[..],
                                                      &import.subclass,
                                                      span);
@@ -1015,6 +1020,14 @@ impl<'a, 'b:'a> ImportResolver<'a, 'b> {
 fn import_path_to_string(names: &[SpannedIdent],
                          subclass: &ImportDirectiveSubclass,
                          span: Span) -> String {
+    info!(
+        "import_path_to_string(names={:?} ({:p}/{}), subclass={:?}, span={:?})",
+        names,
+        names.as_ptr(),
+        names.len(),
+        subclass,
+        span,
+    );
     let pos = names.iter()
         .position(|p| span == p.span && p.node.name != keywords::CrateRoot.name());
     let global = !names.is_empty() && names[0].node.name == keywords::CrateRoot.name();
@@ -1026,6 +1039,8 @@ fn import_path_to_string(names: &[SpannedIdent],
         if names.is_empty() {
             import_directive_subclass_to_string(subclass)
         } else {
+            // FIXME: Remove this entire logic after #48116 is fixed.
+            //
             // Note that this code looks a little wonky, it's currently here to
             // hopefully help debug #48116, but otherwise isn't intended to
             // cause any problems.
@@ -1034,8 +1049,18 @@ fn import_path_to_string(names: &[SpannedIdent],
                 names_to_string(names),
                 import_directive_subclass_to_string(subclass),
             );
-            assert!(!names.is_empty());
-            assert!(!x.starts_with("::"));
+            if names.is_empty() || x.starts_with("::") {
+                span_bug!(
+                    span,
+                    "invalid name `{}` at {:?}; global = {}, names = {:p}/{}, subclass = {:?}",
+                    x,
+                    span,
+                    global,
+                    names.as_ptr(),
+                    names.len(),
+                    subclass
+                );
+            }
             return x
         }
     }

src/test/compile-fail/rfc-2126-extern-in-paths/single-segment.rs

@@ -9,6 +9,7 @@
 // except according to those terms.
 
 // aux-build:xcrate.rs
+// rustc-env:RUST_LOG=info
 
 #![feature(extern_in_paths)]
 
@@ -20,4 +21,4 @@ use extern::*; //~ ERROR unresolved import `extern::*`
 fn main() {
     let s = extern::xcrate; //~ ERROR expected value, found module `extern::xcrate`
                             //~^ NOTE not a value
-}
+}   //~ ERROR must fail kthxbye

src/tools/compiletest/src/runtest.rs

@@ -250,6 +250,7 @@ impl<'test> TestCx<'test> {
     fn run_cfail_test(&self) {
         let proc_res = self.compile_test();
         self.check_if_test_should_compile(&proc_res);
+        self.check_no_compiler_crash(&proc_res);
 
         let output_to_check = self.get_output(&proc_res);
         let expected_errors = errors::load_errors(&self.testpaths.file, self.revision);
@@ -262,7 +263,6 @@ impl<'test> TestCx<'test> {
             self.check_error_patterns(&output_to_check, &proc_res);
         }
 
-        self.check_no_compiler_crash(&proc_res);
         self.check_forbid_output(&output_to_check, &proc_res);
     }