Fix crash when a contract range warning is emitted for a module already in plt

Warnings about wrong contract ranges are post-processed to be displayed in the
file/line that contains the contract, although they can also be emitted while
processing other modules. For this relocation to succeed the module that
contains the contract should be currently under analysis. If this is not the
case the warning is displayed in the file/line of the call that proves the
discrepancy in the contract.

1 files changed, 20 insertions, 13 deletions

diff --git a/lib/dialyzer/src/dialyzer_succ_typings.erl b/lib/dialyzer/src/dialyzer_succ_typings.erl
index b8da57d3f9..dc5a3fed37 100644
--- a/lib/dialyzer/src/dialyzer_succ_typings.erl
+++ b/lib/dialyzer/src/dialyzer_succ_typings.erl
@@ -158,20 +158,27 @@ postprocess_dataflow_warns([], _State, WAcc, Acc) ->
 postprocess_dataflow_warns([{?WARN_CONTRACT_RANGE, {CallF, CallL}, Msg}|Rest],
 			   #st{codeserver = Codeserver} = State, WAcc, Acc) ->
   {contract_range, [Contract, M, F, A, ArgStrings, CRet]} = Msg,
-  {ok, {{ContrF, _ContrL} = FileLine, _C}} =
-    dialyzer_codeserver:lookup_mfa_contract({M,F,A}, Codeserver),
-  case CallF =:= ContrF of
-    true ->
+  case dialyzer_codeserver:lookup_mfa_contract({M,F,A}, Codeserver) of
+    {ok, {{ContrF, _ContrL} = FileLine, _C}} ->
+      case CallF =:= ContrF of
+	true ->
+	  NewMsg = {contract_range, [Contract, M, F, ArgStrings, CallL, CRet]},
+	  W = {?WARN_CONTRACT_RANGE, FileLine, NewMsg},
+	  Filter =
+	    fun({?WARN_CONTRACT_TYPES, FL, _}) when FL =:= FileLine -> false;
+	       (_) -> true
+	    end,
+	  FilterWAcc = lists:filter(Filter, WAcc),
+	  postprocess_dataflow_warns(Rest, State, FilterWAcc, [W|Acc]);
+	false ->
+	  postprocess_dataflow_warns(Rest, State, WAcc, Acc)
+      end;
+    error ->
+      %% The contract is not in a module that is currently under analysis.
+      %% We display the warning in the file/line of the call.
       NewMsg = {contract_range, [Contract, M, F, ArgStrings, CallL, CRet]},
-      W = {?WARN_CONTRACT_RANGE, FileLine, NewMsg},
-      Filter =
-	fun({?WARN_CONTRACT_TYPES, FL, _}) when FL =:= FileLine -> false;
-	   (_) -> true
-	end,
-      FilterWAcc = lists:filter(Filter, WAcc),
-      postprocess_dataflow_warns(Rest, State, FilterWAcc, [W|Acc]);
-    false ->
-      postprocess_dataflow_warns(Rest, State, WAcc, Acc)
+      W = {?WARN_CONTRACT_RANGE, {CallF, CallL}, NewMsg},
+      postprocess_dataflow_warns(Rest, State, WAcc, [W|Acc])
   end;
 postprocess_dataflow_warns([W|Rest], State, Wacc, Acc) ->
   postprocess_dataflow_warns(Rest, State, Wacc, [W|Acc]).