diff --git a/src/librustc/dep_graph/edges.rs b/src/librustc/dep_graph/edges.rs
index 4b25285c476..d3ced8aa518 100644
--- a/src/librustc/dep_graph/edges.rs
+++ b/src/librustc/dep_graph/edges.rs
@@ -122,7 +122,7 @@ impl DepGraphEdges {
     {
         match self.current_node() {
             Some(open_node) => self.add_edge_from_open_node(open_node, op),
-            None => panic!("no current node, cannot add edge into dependency graph")
+            None => bug!("no current node, cannot add edge into dependency graph")
         }
     }
 
diff --git a/src/librustc/dep_graph/thread.rs b/src/librustc/dep_graph/thread.rs
index c43b4b15b76..1b1d3469bc5 100644
--- a/src/librustc/dep_graph/thread.rs
+++ b/src/librustc/dep_graph/thread.rs
@@ -148,7 +148,7 @@ impl DepGraphThreadData {
 
     // Outline this too.
     fn invalid_message(&self, string: &str) {
-        panic!("{}; see src/librustc/dep_graph/README.md for more information", string)
+        bug!("{}; see src/librustc/dep_graph/README.md for more information", string)
     }
 }
 
diff --git a/src/librustc/front/map/blocks.rs b/src/librustc/front/map/blocks.rs
index 976a8c6dda0..2eb3d56bb5e 100644
--- a/src/librustc/front/map/blocks.rs
+++ b/src/librustc/front/map/blocks.rs
@@ -231,13 +231,13 @@ impl<'a> FnLikeNode<'a> {
                         span: i.span,
                         attrs: &i.attrs,
                     }),
-                _ => panic!("item FnLikeNode that is not fn-like"),
+                _ => bug!("item FnLikeNode that is not fn-like"),
             },
             map::NodeTraitItem(ti) => match ti.node {
                 ast::MethodTraitItem(ref sig, Some(ref body)) => {
                     method(ti.id, ti.name, sig, None, body, ti.span, &ti.attrs)
                 }
-                _ => panic!("trait method FnLikeNode that is not fn-like"),
+                _ => bug!("trait method FnLikeNode that is not fn-like"),
             },
             map::NodeImplItem(ii) => {
                 match ii.node {
@@ -245,7 +245,7 @@ impl<'a> FnLikeNode<'a> {
                         method(ii.id, ii.name, sig, Some(ii.vis), body, ii.span, &ii.attrs)
                     }
                     _ => {
-                        panic!("impl method FnLikeNode that is not fn-like")
+                        bug!("impl method FnLikeNode that is not fn-like")
                     }
                 }
             }
@@ -256,9 +256,9 @@ impl<'a> FnLikeNode<'a> {
                                               e.id,
                                               e.span,
                                               e.attrs.as_attr_slice())),
-                _ => panic!("expr FnLikeNode that is not fn-like"),
+                _ => bug!("expr FnLikeNode that is not fn-like"),
             },
-            _ => panic!("other FnLikeNode that is not fn-like"),
+            _ => bug!("other FnLikeNode that is not fn-like"),
         }
     }
 }
diff --git a/src/librustc/front/map/mod.rs b/src/librustc/front/map/mod.rs
index 3605de44495..817bec58407 100644
--- a/src/librustc/front/map/mod.rs
+++ b/src/librustc/front/map/mod.rs
@@ -335,9 +335,9 @@ impl<'ast> Map<'ast> {
                     return self.opt_local_def_id(id)
                                .map(|def_id| DepNode::Hir(def_id))
                                .unwrap_or_else(|| {
-                                   panic!("Walking parents from `{}` \
-                                           led to `NotPresent` at `{}`",
-                                          id0, id)
+                                   bug!("Walking parents from `{}` \
+                                         led to `NotPresent` at `{}`",
+                                        id0, id)
                                }),
             }
         }
@@ -363,8 +363,8 @@ impl<'ast> Map<'ast> {
 
     pub fn local_def_id(&self, node: NodeId) -> DefId {
         self.opt_local_def_id(node).unwrap_or_else(|| {
-            panic!("local_def_id: no entry for `{}`, which has a map of `{:?}`",
-                   node, self.find_entry(node))
+            bug!("local_def_id: no entry for `{}`, which has a map of `{:?}`",
+                 node, self.find_entry(node))
         })
     }
 
@@ -402,7 +402,7 @@ impl<'ast> Map<'ast> {
     pub fn get(&self, id: NodeId) -> Node<'ast> {
         match self.find(id) {
             Some(node) => node, // read recorded by `find`
-            None => panic!("couldn't find node id {} in the AST map", id)
+            None => bug!("couldn't find node id {} in the AST map", id)
         }
     }
 
@@ -576,7 +576,7 @@ impl<'ast> Map<'ast> {
                 self.read(id); // reveals some of the content of a node
                 abi
             }
-            None => panic!("expected foreign mod or inlined parent, found {}",
+            None => bug!("expected foreign mod or inlined parent, found {}",
                           self.node_to_string(parent))
         }
     }
@@ -584,14 +584,14 @@ impl<'ast> Map<'ast> {
     pub fn expect_item(&self, id: NodeId) -> &'ast Item {
         match self.find(id) { // read recorded by `find`
             Some(NodeItem(item)) => item,
-            _ => panic!("expected item, found {}", self.node_to_string(id))
+            _ => bug!("expected item, found {}", self.node_to_string(id))
         }
     }
 
     pub fn expect_trait_item(&self, id: NodeId) -> &'ast TraitItem {
         match self.find(id) {
             Some(NodeTraitItem(item)) => item,
-            _ => panic!("expected trait item, found {}", self.node_to_string(id))
+            _ => bug!("expected trait item, found {}", self.node_to_string(id))
         }
     }
 
@@ -600,38 +600,38 @@ impl<'ast> Map<'ast> {
             Some(NodeItem(i)) => {
                 match i.node {
                     ItemStruct(ref struct_def, _) => struct_def,
-                    _ => panic!("struct ID bound to non-struct")
+                    _ => bug!("struct ID bound to non-struct")
                 }
             }
             Some(NodeVariant(variant)) => {
                 if variant.node.data.is_struct() {
                     &variant.node.data
                 } else {
-                    panic!("struct ID bound to enum variant that isn't struct-like")
+                    bug!("struct ID bound to enum variant that isn't struct-like")
                 }
             }
-            _ => panic!(format!("expected struct, found {}", self.node_to_string(id))),
+            _ => bug!("expected struct, found {}", self.node_to_string(id)),
         }
     }
 
     pub fn expect_variant(&self, id: NodeId) -> &'ast Variant {
         match self.find(id) {
             Some(NodeVariant(variant)) => variant,
-            _ => panic!(format!("expected variant, found {}", self.node_to_string(id))),
+            _ => bug!("expected variant, found {}", self.node_to_string(id)),
         }
     }
 
     pub fn expect_foreign_item(&self, id: NodeId) -> &'ast ForeignItem {
         match self.find(id) {
             Some(NodeForeignItem(item)) => item,
-            _ => panic!("expected foreign item, found {}", self.node_to_string(id))
+            _ => bug!("expected foreign item, found {}", self.node_to_string(id))
         }
     }
 
     pub fn expect_expr(&self, id: NodeId) -> &'ast Expr {
         match self.find(id) { // read recorded by find
             Some(NodeExpr(expr)) => expr,
-            _ => panic!("expected expr, found {}", self.node_to_string(id))
+            _ => bug!("expected expr, found {}", self.node_to_string(id))
         }
     }
 
@@ -656,7 +656,7 @@ impl<'ast> Map<'ast> {
             NodeLocal(&Pat { node: PatKind::Ident(_,l,_), .. }) => {
                 PathName(l.node.name)
             },
-            _ => panic!("no path elem for {:?}", node)
+            _ => bug!("no path elem for {:?}", node)
         }
     }
 
@@ -773,7 +773,7 @@ impl<'ast> Map<'ast> {
     pub fn span(&self, id: NodeId) -> Span {
         self.read(id); // reveals span from node
         self.opt_span(id)
-            .unwrap_or_else(|| panic!("AstMap.span: could not find span for id {:?}", id))
+            .unwrap_or_else(|| bug!("AstMap.span: could not find span for id {:?}", id))
     }
 
     pub fn span_if_local(&self, id: DefId) -> Option<Span> {
@@ -1019,12 +1019,12 @@ impl<'a> NodePrinter for pprust::State<'a> {
             NodePat(a)         => self.print_pat(&a),
             NodeBlock(a)       => self.print_block(&a),
             NodeLifetime(a)    => self.print_lifetime(&a),
-            NodeTyParam(_)     => panic!("cannot print TyParam"),
+            NodeTyParam(_)     => bug!("cannot print TyParam"),
             // these cases do not carry enough information in the
             // ast_map to reconstruct their full structure for pretty
             // printing.
-            NodeLocal(_)       => panic!("cannot print isolated Local"),
-            NodeStructCtor(_)  => panic!("cannot print isolated StructCtor"),
+            NodeLocal(_)       => bug!("cannot print isolated Local"),
+            NodeStructCtor(_)  => bug!("cannot print isolated StructCtor"),
         }
     }
 }
diff --git a/src/librustc/infer/error_reporting.rs b/src/librustc/infer/error_reporting.rs
index 20c01344144..8079a6d1bbc 100644
--- a/src/librustc/infer/error_reporting.rs
+++ b/src/librustc/infer/error_reporting.rs
@@ -404,7 +404,7 @@ impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> {
                     bound_failures.push((origin.clone(), kind.clone(), region));
                 }
                 ProcessedErrors(..) => {
-                    panic!("should not encounter a `ProcessedErrors` yet: {:?}", error)
+                    bug!("should not encounter a `ProcessedErrors` yet: {:?}", error)
                 }
             }
         }
diff --git a/src/librustc/infer/region_inference/graphviz.rs b/src/librustc/infer/region_inference/graphviz.rs
index 8200e7825a0..e611c005691 100644
--- a/src/librustc/infer/region_inference/graphviz.rs
+++ b/src/librustc/infer/region_inference/graphviz.rs
@@ -182,13 +182,13 @@ impl<'a, 'tcx> dot::Labeller<'a> for ConstraintGraph<'a, 'tcx> {
     fn node_id(&self, n: &Node) -> dot::Id {
         let node_id = match self.node_ids.get(n) {
             Some(node_id) => node_id,
-            None => panic!("no node_id found for node: {:?}", n),
+            None => bug!("no node_id found for node: {:?}", n),
         };
         let name = || format!("node_{}", node_id);
         match dot::Id::new(name()) {
             Ok(id) => id,
             Err(_) => {
-                panic!("failed to create graphviz node identified by {}", name());
+                bug!("failed to create graphviz node identified by {}", name());
             }
         }
     }
diff --git a/src/librustc/infer/region_inference/mod.rs b/src/librustc/infer/region_inference/mod.rs
index 32eeb9c4ea3..2f610bf2380 100644
--- a/src/librustc/infer/region_inference/mod.rs
+++ b/src/librustc/infer/region_inference/mod.rs
@@ -309,7 +309,7 @@ impl<'a, 'tcx> RegionVarBindings<'a, 'tcx> {
         while undo_log.len() > snapshot.length + 1 {
             match undo_log.pop().unwrap() {
                 OpenSnapshot => {
-                    panic!("Failure to observe stack discipline");
+                    bug!("Failure to observe stack discipline");
                 }
                 CommitedSnapshot => {}
                 AddVar(vid) => {
diff --git a/src/librustc/infer/type_variable.rs b/src/librustc/infer/type_variable.rs
index 141556c102d..3cc076f1f00 100644
--- a/src/librustc/infer/type_variable.rs
+++ b/src/librustc/infer/type_variable.rs
@@ -159,8 +159,8 @@ impl<'tcx> TypeVariableTable<'tcx> {
 
         let (relations, default) = match old_value {
             Bounded { relations, default } => (relations, default),
-            Known(_) => panic!("Asked to instantiate variable that is \
-                               already instantiated")
+            Known(_) => bug!("Asked to instantiate variable that is \
+                              already instantiated")
         };
 
         for &(dir, vid) in &relations {
@@ -318,7 +318,7 @@ impl<'tcx> sv::SnapshotVecDelegate for Delegate<'tcx> {
 
 fn relations<'a>(v: &'a mut TypeVariableData) -> &'a mut Vec<Relation> {
     match v.value {
-        Known(_) => panic!("var_sub_var: variable is known"),
+        Known(_) => bug!("var_sub_var: variable is known"),
         Bounded { ref mut relations, .. } => relations
     }
 }
diff --git a/src/librustc/lint/context.rs b/src/librustc/lint/context.rs
index 7e6eb0146fc..e78ff513ac4 100644
--- a/src/librustc/lint/context.rs
+++ b/src/librustc/lint/context.rs
@@ -232,7 +232,7 @@ impl LintStore {
     pub fn register_renamed(&mut self, old_name: &str, new_name: &str) {
         let target = match self.by_name.get(new_name) {
             Some(&Id(lint_id)) => lint_id.clone(),
-            _ => panic!("invalid lint renaming of {} to {}", old_name, new_name)
+            _ => bug!("invalid lint renaming of {} to {}", old_name, new_name)
         };
         self.by_name.insert(old_name.to_string(), Renamed(new_name.to_string(), target));
     }
@@ -430,7 +430,7 @@ pub fn raw_struct_lint<'a>(sess: &'a Session,
             format!("{} [-{} {}]", msg,
                     match level {
                         Warn => 'W', Deny => 'D', Forbid => 'F',
-                        Allow => panic!()
+                        Allow => bug!()
                     }, name.replace("_", "-"))
         },
         Node(src) => {
diff --git a/src/librustc/middle/cstore.rs b/src/librustc/middle/cstore.rs
index 305b64f3320..4efb40abdb0 100644
--- a/src/librustc/middle/cstore.rs
+++ b/src/librustc/middle/cstore.rs
@@ -309,7 +309,7 @@ pub fn validate_crate_name(sess: Option<&Session>, s: &str, sp: Option<Span>) {
     {
         let mut say = |s: &str| {
             match (sp, sess) {
-                (_, None) => panic!("{}", s),
+                (_, None) => bug!("{}", s),
                 (Some(sp), Some(sess)) => sess.span_err(sp, s),
                 (None, Some(sess)) => sess.err(s),
             }
diff --git a/src/librustc/middle/def.rs b/src/librustc/middle/def.rs
index 6cbcd41d84a..e6ea000936c 100644
--- a/src/librustc/middle/def.rs
+++ b/src/librustc/middle/def.rs
@@ -71,7 +71,7 @@ impl PathResolution {
     /// Get the definition, if fully resolved, otherwise panic.
     pub fn full_def(&self) -> Def {
         if self.depth != 0 {
-            panic!("path not fully resolved: {:?}", self);
+            bug!("path not fully resolved: {:?}", self);
         }
         self.base_def
     }
@@ -116,7 +116,7 @@ impl Def {
             Def::TyParam(..) | Def::Struct(..) | Def::Trait(..) |
             Def::Method(..) | Def::Const(..) | Def::AssociatedConst(..) |
             Def::PrimTy(..) | Def::Label(..) | Def::SelfTy(..) | Def::Err => {
-                panic!("attempted .var_id() on invalid {:?}", self)
+                bug!("attempted .var_id() on invalid {:?}", self)
             }
         }
     }
@@ -135,7 +135,7 @@ impl Def {
             Def::PrimTy(..) |
             Def::SelfTy(..) |
             Def::Err => {
-                panic!("attempted .def_id() on invalid def: {:?}", self)
+                bug!("attempted .def_id() on invalid def: {:?}", self)
             }
         }
     }
diff --git a/src/librustc/middle/mem_categorization.rs b/src/librustc/middle/mem_categorization.rs
index 1eb0a9956d0..ef031ad13f1 100644
--- a/src/librustc/middle/mem_categorization.rs
+++ b/src/librustc/middle/mem_categorization.rs
@@ -611,7 +611,7 @@ impl<'t, 'a,'tcx> MemCategorizationContext<'t, 'a, 'tcx> {
             }))
           }
 
-          Def::Err => panic!("Def::Err in memory categorization")
+          Def::Err => bug!("Def::Err in memory categorization")
         }
     }
 
diff --git a/src/librustc/middle/region.rs b/src/librustc/middle/region.rs
index 7a607e2419d..2cde6ce9320 100644
--- a/src/librustc/middle/region.rs
+++ b/src/librustc/middle/region.rs
@@ -343,7 +343,7 @@ impl RegionMaps {
     pub fn lookup_code_extent(&self, e: CodeExtentData) -> CodeExtent {
         match self.code_extent_interner.borrow().get(&e) {
             Some(&d) => d,
-            None => panic!("unknown code extent {:?}", e)
+            None => bug!("unknown code extent {:?}", e)
         }
     }
     pub fn node_extent(&self, n: ast::NodeId) -> CodeExtent {
@@ -470,7 +470,7 @@ impl RegionMaps {
     pub fn var_scope(&self, var_id: ast::NodeId) -> CodeExtent {
         match self.var_map.borrow().get(&var_id) {
             Some(&r) => r,
-            None => { panic!("no enclosing scope for id {:?}", var_id); }
+            None => { bug!("no enclosing scope for id {:?}", var_id); }
         }
     }
 
diff --git a/src/librustc/session/filesearch.rs b/src/librustc/session/filesearch.rs
index 09c6b54d99c..e54acf3fdc3 100644
--- a/src/librustc/session/filesearch.rs
+++ b/src/librustc/session/filesearch.rs
@@ -155,14 +155,14 @@ pub fn get_or_default_sysroot() -> PathBuf {
                 // gcc chokes on verbatim paths which fs::canonicalize generates
                 // so we try to avoid those kinds of paths.
                 Ok(canon) => Some(rustcfs::fix_windows_verbatim_for_gcc(&canon)),
-                Err(e) => panic!("failed to get realpath: {}", e),
+                Err(e) => bug!("failed to get realpath: {}", e),
             }
         })
     }
 
     match canonicalize(env::current_exe().ok()) {
         Some(mut p) => { p.pop(); p.pop(); p }
-        None => panic!("can't determine value for sysroot")
+        None => bug!("can't determine value for sysroot")
     }
 }
 
diff --git a/src/librustc/traits/specialize/specialization_graph.rs b/src/librustc/traits/specialize/specialization_graph.rs
index eaafeb1a969..d3146697ee6 100644
--- a/src/librustc/traits/specialize/specialization_graph.rs
+++ b/src/librustc/traits/specialize/specialization_graph.rs
@@ -145,8 +145,8 @@ impl Graph {
     /// Insert cached metadata mapping from a child impl back to its parent.
     pub fn record_impl_from_cstore(&mut self, parent: DefId, child: DefId) {
         if self.parent.insert(child, parent).is_some() {
-            panic!("When recording an impl from the crate store, information about its parent \
-                    was already present.");
+            bug!("When recording an impl from the crate store, information about its parent \
+                  was already present.");
         }
 
         self.children.entry(parent).or_insert(vec![]).push(child);
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index b52460f6c57..edfad09ae1f 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -1647,7 +1647,7 @@ impl<'tcx, 'container> AdtDefData<'tcx, 'container> {
         match def {
             Def::Variant(_, vid) => self.variant_with_id(vid),
             Def::Struct(..) | Def::TyAlias(..) => self.struct_variant(),
-            _ => panic!("unexpected def {:?} in variant_of_def", def)
+            _ => bug!("unexpected def {:?} in variant_of_def", def)
         }
     }
 
@@ -1857,7 +1857,7 @@ fn lookup_locally_or_in_crate_store<M, F>(descr: &str,
 {
     map.memoize(def_id, || {
         if def_id.is_local() {
-            panic!("No def'n found for {:?} in tcx.{}", def_id, descr);
+            bug!("No def'n found for {:?} in tcx.{}", def_id, descr);
         }
         load_external()
     })
diff --git a/src/librustc/ty/sty.rs b/src/librustc/ty/sty.rs
index 191c261b7e3..fee0aaff445 100644
--- a/src/librustc/ty/sty.rs
+++ b/src/librustc/ty/sty.rs
@@ -987,14 +987,14 @@ impl<'tcx> TyS<'tcx> {
             TyStruct(def, substs) => {
                 def.struct_variant().fields[0].ty(cx, substs)
             }
-            _ => panic!("simd_type called on invalid type")
+            _ => bug!("simd_type called on invalid type")
         }
     }
 
     pub fn simd_size(&self, _cx: &TyCtxt) -> usize {
         match self.sty {
             TyStruct(def, _) => def.struct_variant().fields.len(),
-            _ => panic!("simd_size called on invalid type")
+            _ => bug!("simd_size called on invalid type")
         }
     }
 
@@ -1147,7 +1147,7 @@ impl<'tcx> TyS<'tcx> {
     pub fn fn_sig(&self) -> &'tcx PolyFnSig<'tcx> {
         match self.sty {
             TyFnDef(_, _, ref f) | TyFnPtr(ref f) => &f.sig,
-            _ => panic!("Ty::fn_sig() called on non-fn type: {:?}", self)
+            _ => bug!("Ty::fn_sig() called on non-fn type: {:?}", self)
         }
     }
 
@@ -1155,7 +1155,7 @@ impl<'tcx> TyS<'tcx> {
     pub fn fn_abi(&self) -> abi::Abi {
         match self.sty {
             TyFnDef(_, _, ref f) | TyFnPtr(ref f) => f.abi,
-            _ => panic!("Ty::fn_abi() called on non-fn type"),
+            _ => bug!("Ty::fn_abi() called on non-fn type"),
         }
     }
 
diff --git a/src/librustc/ty/subst.rs b/src/librustc/ty/subst.rs
index 81f50e2e0a1..5b05c632a97 100644
--- a/src/librustc/ty/subst.rs
+++ b/src/librustc/ty/subst.rs
@@ -193,7 +193,7 @@ impl ParamSpace {
             0 => TypeSpace,
             1 => SelfSpace,
             2 => FnSpace,
-            _ => panic!("Invalid ParamSpace: {}", u)
+            _ => bug!("Invalid ParamSpace: {}", u)
         }
     }
 }
diff --git a/src/librustc/ty/util.rs b/src/librustc/ty/util.rs
index e5f2e5fc70a..6e8363f629b 100644
--- a/src/librustc/ty/util.rs
+++ b/src/librustc/ty/util.rs
@@ -88,7 +88,7 @@ impl IntTypeExt for attr::IntType {
             (UnsignedInt(ast::UintTy::U32), ConstInt::U32(_)) => {},
             (UnsignedInt(ast::UintTy::U64), ConstInt::U64(_)) => {},
             (UnsignedInt(ast::UintTy::Us), ConstInt::Usize(_)) => {},
-            _ => panic!("disr type mismatch: {:?} vs {:?}", self, val),
+            _ => bug!("disr type mismatch: {:?} vs {:?}", self, val),
         }
     }