Allow panicking with string literal messages inside constants

4 files changed, 23 insertions, 4 deletions

diff --git a/src/librustc/ich/impls_ty.rs b/src/librustc/ich/impls_ty.rs
index 46f4ed4ec47..54829058f44 100644
--- a/src/librustc/ich/impls_ty.rs
+++ b/src/librustc/ich/impls_ty.rs
@@ -536,7 +536,6 @@ for ::mir::interpret::EvalErrorKind<'gcx, O> {
             DeallocateNonBasePtr |
             HeapAllocZeroBytes |
             Unreachable |
-            Panic |
             ReadFromReturnPointer |
             UnimplementedTraitSelection |
             TypeckError |
@@ -550,6 +549,12 @@ for ::mir::interpret::EvalErrorKind<'gcx, O> {
             GeneratorResumedAfterReturn |
             GeneratorResumedAfterPanic |
             InfiniteLoop => {}
+            Panic { ref msg, ref file, line, col } => {
+                msg.hash_stable(hcx, hasher);
+                file.hash_stable(hcx, hasher);
+                line.hash_stable(hcx, hasher);
+                col.hash_stable(hcx, hasher);
+            },
             ReferencedConstant(ref err) => err.hash_stable(hcx, hasher),
             MachineError(ref err) => err.hash_stable(hcx, hasher),
             FunctionPointerTyMismatch(a, b) => {
diff --git a/src/librustc/middle/lang_items.rs b/src/librustc/middle/lang_items.rs
index cf94a0fb4b4..8c300a0aba0 100644
--- a/src/librustc/middle/lang_items.rs
+++ b/src/librustc/middle/lang_items.rs
@@ -305,6 +305,8 @@ language_item_table! {
     PanicBoundsCheckFnLangItem,      "panic_bounds_check",      panic_bounds_check_fn;
     PanicInfoLangItem,               "panic_info",              panic_info;
     PanicImplLangItem,               "panic_impl",              panic_impl;
+    // Libstd panic entry point. Necessary for const eval to be able to catch it
+    BeginPanicFnLangItem,            "begin_panic",             begin_panic_fn;
 
     ExchangeMallocFnLangItem,        "exchange_malloc",         exchange_malloc_fn;
     BoxFreeFnLangItem,               "box_free",                box_free_fn;
diff --git a/src/librustc/mir/interpret/error.rs b/src/librustc/mir/interpret/error.rs
index 1e9584bc55b..436478b8416 100644
--- a/src/librustc/mir/interpret/error.rs
+++ b/src/librustc/mir/interpret/error.rs
@@ -17,6 +17,7 @@ use errors::DiagnosticBuilder;
 
 use syntax_pos::Span;
 use syntax::ast;
+use syntax::symbol::Symbol;
 
 pub type ConstEvalResult<'tcx> = Result<&'tcx ty::Const<'tcx>, Lrc<ConstEvalErr<'tcx>>>;
 
@@ -250,7 +251,12 @@ pub enum EvalErrorKind<'tcx, O> {
     HeapAllocZeroBytes,
     HeapAllocNonPowerOfTwoAlignment(u64),
     Unreachable,
-    Panic,
+    Panic {
+        msg: Symbol,
+        line: u32,
+        col: u32,
+        file: Symbol,
+    },
     ReadFromReturnPointer,
     PathNotFound(Vec<String>),
     UnimplementedTraitSelection,
@@ -370,7 +376,7 @@ impl<'tcx, O> EvalErrorKind<'tcx, O> {
                 "tried to re-, de-, or allocate heap memory with alignment that is not a power of two",
             Unreachable =>
                 "entered unreachable code",
-            Panic =>
+            Panic { .. } =>
                 "the evaluated program panicked",
             ReadFromReturnPointer =>
                 "tried to read from the return pointer",
@@ -465,6 +471,8 @@ impl<'tcx, O: fmt::Debug> fmt::Debug for EvalErrorKind<'tcx, O> {
                 write!(f, "{}", inner),
             IncorrectAllocationInformation(size, size2, align, align2) =>
                 write!(f, "incorrect alloc info: expected size {} and align {}, got size {} and align {}", size.bytes(), align.abi(), size2.bytes(), align2.abi()),
+            Panic { ref msg, line, col, ref file } =>
+                write!(f, "the evaluated program panicked at '{}', {}:{}:{}", msg, file, line, col),
             _ => write!(f, "{}", self.description()),
         }
     }
diff --git a/src/librustc/ty/structural_impls.rs b/src/librustc/ty/structural_impls.rs
index ad29f808285..95e2cc6c387 100644
--- a/src/librustc/ty/structural_impls.rs
+++ b/src/librustc/ty/structural_impls.rs
@@ -574,7 +574,11 @@ impl<'a, 'tcx, O: Lift<'tcx>> Lift<'tcx> for interpret::EvalErrorKind<'a, O> {
             HeapAllocZeroBytes => HeapAllocZeroBytes,
             HeapAllocNonPowerOfTwoAlignment(n) => HeapAllocNonPowerOfTwoAlignment(n),
             Unreachable => Unreachable,
-            Panic => Panic,
+            Panic { ref msg, ref file, line, col } => Panic {
+                msg: msg.clone(),
+                file: file.clone(),
+                line, col,
+            },
             ReadFromReturnPointer => ReadFromReturnPointer,
             PathNotFound(ref v) => PathNotFound(v.clone()),
             UnimplementedTraitSelection => UnimplementedTraitSelection,