v3_core: Fix compiler crash when compiling failing binary construction

The compiler would crash when compiling code such as the following
because the binding of `Var` was not done because the binary
construction would always fail:

    case <<(Var = 1),[]/utf32>> of
        _ when Var -> true
    end.

(Also see 0f53ac61d9ce.)

2 files changed, 24 insertions, 5 deletions

diff --git a/lib/compiler/src/v3_core.erl b/lib/compiler/src/v3_core.erl
index 6a93f30f81..e38cfcbaa7 100644
--- a/lib/compiler/src/v3_core.erl
+++ b/lib/compiler/src/v3_core.erl
@@ -1144,11 +1144,24 @@ make_combined(Line, Val, Size) ->
      {integer,Line,Size},
      [integer,{unit,1},unsigned,big]}.
 
-expr_bin_1(Es, St) ->
-    foldr(fun (E, {Ces,Esp,St0}) ->
-		  {Ce,Ep,St1} = bitstr(E, St0),
-		  {[Ce|Ces],Ep ++ Esp,St1}
-	  end, {[],[],St}, Es).
+expr_bin_1(Es, St0) ->
+    Res = foldr(fun (E, {Ces,Eps0,S0}) ->
+                        try bitstr(E, S0) of
+                            {Ce,Eps,S1} when is_list(Ces) ->
+                                {[Ce|Ces],Eps ++ Eps0,S1};
+                            {_Ce,Eps,S1} ->
+                                {Ces,Eps ++ Eps0,S1}
+                        catch
+                            {bad_binary,Eps,S1} ->
+                                {bad_binary,Eps ++ Eps0,S1}
+                        end
+                end, {[],[],St0}, Es),
+    case Res of
+        {bad_binary,Eps,St} ->
+            throw({bad_binary,Eps,St});
+        {_,_,_}=Res ->
+            Res
+    end.
 
 bitstr({bin_element,_,E0,Size0,[Type,{unit,Unit}|Flags]}, St0) ->
     {E1,Eps0,St1} = safe(E0, St0),
diff --git a/lib/compiler/test/bs_construct_SUITE.erl b/lib/compiler/test/bs_construct_SUITE.erl
index f428c3a27f..9df5f4aa0c 100644
--- a/lib/compiler/test/bs_construct_SUITE.erl
+++ b/lib/compiler/test/bs_construct_SUITE.erl
@@ -343,6 +343,7 @@ fail(Config) when is_list(Config) ->
                                  end),
     {'EXIT',{badarg,_}} = (catch <<13:(put(?FUNCTION_NAME, 17))>>),
     17 = erase(?FUNCTION_NAME),
+    {'EXIT',{badarg,_}} = (catch fail_1()),
 
     %% Size exceeds length of binary. 'native' is redundant for
     %% binaries, but when it was present sys_core_fold would not
@@ -352,6 +353,11 @@ fail(Config) when is_list(Config) ->
 
     ok.
 
+fail_1() ->
+    case <<(V0 = 1),[]/utf32>> of
+        _ when V0 -> true
+    end.
+
 float_bin(Config) when is_list(Config) ->
     %% Some more coverage.
     {<<1,2,3>>,7.0} = float_bin_1(4),