beam_validator: Eliminate dialyzer warnings for unmatched returns

The assert_fls/2 and assert_type/3 functions both return the
Vst passed to them, but all callers ignore the return value.
Given the name of the functions, they are not expected to return
anything. Make it so by changing the return value to 'ok'.

There are two calls to bsm_get_context/2 used only to validate
that the match context is valid. Call bsm_validate_context/2
instead.

In bsm_validate_context/2, explicitly match the return value of
bsm_get_context/2 to '_' to make it clear that it is not used.

1 files changed, 7 insertions, 7 deletions

diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl
index 58aba0b9cc..eb72290306 100644
--- a/lib/compiler/src/beam_validator.erl
+++ b/lib/compiler/src/beam_validator.erl
@@ -649,7 +649,8 @@ valfun_4(send, Vst) ->
     call(send, 2, Vst);
 valfun_4({set_tuple_element,Src,Tuple,I}, Vst) ->
     assert_term(Src, Vst),
-    assert_type({tuple_element,I+1}, Tuple, Vst);
+    assert_type({tuple_element,I+1}, Tuple, Vst),
+    Vst;
 %% Match instructions.
 valfun_4({select_val,Src,{f,Fail},{list,Choices}}, Vst) ->
     assert_term(Src, Vst),
@@ -1044,7 +1045,7 @@ float_op(Src, Dst, Vst0) ->
 
 assert_fls(Fls, Vst) ->
     case get_fls(Vst) of
-	Fls -> Vst;
+	Fls -> ok;
 	OtherFls -> error({bad_floating_point_state,OtherFls})
     end.
 
@@ -1120,7 +1121,7 @@ bsm_match_state(Slots) ->
     {match_context,0,Slots}.
 
 bsm_validate_context(Reg, Vst) ->
-    bsm_get_context(Reg, Vst),
+    _ = bsm_get_context(Reg, Vst),
     ok.
 
 bsm_get_context({x,X}=Reg, #vst{current=#st{x=Xs}}=_Vst) when is_integer(X) ->
@@ -1133,7 +1134,7 @@ bsm_get_context(Reg, _) -> error({bad_source,Reg}).
 bsm_save(Reg, {atom,start}, Vst) ->
     %% Save point refering to where the match started.
     %% It is always valid. But don't forget to validate the context register.
-    bsm_get_context(Reg, Vst),
+    bsm_validate_context(Reg, Vst),
     Vst;
 bsm_save(Reg, SavePoint, Vst) ->
     case bsm_get_context(Reg, Vst) of
@@ -1146,7 +1147,7 @@ bsm_save(Reg, SavePoint, Vst) ->
 bsm_restore(Reg, {atom,start}, Vst) ->
     %% (Mostly) automatic save point refering to where the match started.
     %% It is always valid. But don't forget to validate the context register.
-    bsm_get_context(Reg, Vst),
+    bsm_validate_context(Reg, Vst),
     Vst;
 bsm_restore(Reg, SavePoint, Vst) ->
     case bsm_get_context(Reg, Vst) of
@@ -1312,8 +1313,7 @@ assert_term(Src, Vst) ->
 %%
 
 assert_type(WantedType, Term, Vst) ->
-    assert_type(WantedType, get_term_type(Term, Vst)),
-    Vst.
+    assert_type(WantedType, get_term_type(Term, Vst)).
 
 assert_type(Correct, Correct) -> ok;
 assert_type(float, {float,_}) -> ok;