syntax: prevent segfault on null types

Errors on: method calls, attribute access.
Warnings on: null-null comparisons, null casted to non nullable.

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/syntax/typing.nit b/src/syntax/typing.nit
index 97eb5f2..5e75e57 100644 (file)
--- a/src/syntax/typing.nit
+++ b/src/syntax/typing.nit
@@ -695,6 +695,10 @@ redef class AReassignFormExpr
                        return null
                end
                var name = n_assign_op.method_name
+               if type_lvalue isa MMTypeNone then
+                       v.error(self, "Error: Method '{name}' call on 'null'.")
+                       return null
+               end
                var lc = type_lvalue.local_class
                if not lc.has_global_property_by_name(name) then
                        v.error(self, "Error: Method '{name}' doesn't exists in {type_lvalue}.")
@@ -1042,6 +1046,10 @@ redef class AAttrFormExpr
                if not v.check_expr(n_expr) then return
                var type_recv = n_expr.stype
                var name = n_id.to_symbol
+               if type_recv isa MMTypeNone then
+                       v.error(self, "Error: Attribute '{name}' access on 'null'.")
+                       return
+               end
                var lc = type_recv.local_class
                if not lc.has_global_property_by_name(name) then
                        v.error(self, "Error: Attribute {name} doesn't exists in {type_recv}.")
@@ -1234,16 +1242,20 @@ redef class AAbsSendExpr
 
        private fun get_property(v: TypingVisitor, type_recv: MMType, is_implicit_self: Bool, name: Symbol): nullable MMMethod
        do
+               if type_recv isa MMTypeNone then
+                       v.error(self, "Error: Method '{name}' call on 'null'.")
+                       return null
+               end
                var lc = type_recv.local_class
                var prop: nullable MMMethod = null
                if lc.has_global_property_by_name(name) then prop = lc.select_method(name)
                if prop == null and v.local_property.global.is_init then
-                       var props = type_recv.local_class.super_methods_named(name)
+                       var props = lc.super_methods_named(name)
                        if props.length > 1 then
                                v.error(self, "Error: Ambigous method name '{name}' for {props.join(", ")}. Use explicit designation.")
                                return null
                        else if props.length == 1 then 
-                               var p = type_recv.local_class[props.first.global]
+                               var p = lc[props.first.global]
                                assert p isa MMMethod
                                prop = p
                        end
@@ -1436,7 +1448,11 @@ redef class AEqExpr
                end
 
                if n_expr.stype isa MMTypeNone then
-                       try_to_isa(v, n_expr2)
+                       if n_expr2.stype isa MMTypeNone then
+                               v.warning(self, "Warning: comparaison between 2 null values.")
+                       else
+                               try_to_isa(v, n_expr2)
+                       end
                else if n_expr2.stype isa MMTypeNone then
                        try_to_isa(v, n_expr)
                end
@@ -1462,7 +1478,11 @@ redef class ANeExpr
                end
 
                if n_expr.stype isa MMTypeNone then
-                       try_to_isa(v, n_expr2)
+                       if n_expr2.stype isa MMTypeNone then
+                               v.warning(self, "Warning: comparaison between 2 null values.")
+                       else
+                               try_to_isa(v, n_expr2)
+                       end
                else if n_expr2.stype isa MMTypeNone then
                        try_to_isa(v, n_expr)
                end
@@ -1715,6 +1735,9 @@ special AExpr
                        v.warning(self, "Warning: Expression is already a {ttype}.")
                else if etype < ttype then
                        v.warning(self, "Warning: Expression is already a {ttype} since it is a {etype}.")
+               else if etype isa MMTypeNone then
+                       # ttype is not nullable because of prevous test
+                       v.warning(self, "Warning: Expression is null therefore cannot be a {ttype}.")
                else if etype.is_nullable and etype.as_notnull == ttype then
                        if ttype isa MMTypeFormal and ttype.bound.is_nullable then
                                # No warning in this case since with

diff --git a/tests/base_var_null.nit b/tests/base_var_null.nit
new file mode 100644 (file)
index 0000000..c0cb189
--- /dev/null
+++ b/tests/base_var_null.nit
@@ -0,0 +1,51 @@
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Copyright 2009 Jean Privat <jean@pryen.org>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import kernel
+
+class A
+       var _foo: Int = 1
+       fun +(i: Int): A do return new A
+       redef fun output do 1.output
+end
+
+fun unknown: nullable A do return new A
+
+var a = null
+#alt1#a.output
+#alt2#a._foo.output
+#alt3#a._foo = 5
+#alt4#a += 5
+
+var b: nullable A
+b = null
+#alt5#b.output
+#alt6#b._foo.output
+#alt7#b._foo = 5
+#alt8#b += 5
+
+var c = unknown
+if c == null then
+#alt9# c.output
+#alt10#        c._foo.output
+#alt11#        c._foo = 5
+#alt12#        c += 5
+else
+       c.output
+       c._foo.output
+       c._foo = 5
+       c += 5
+end

diff --git a/tests/error_expr_not_ok.nit b/tests/error_expr_not_ok.nit
index edeb2ae..0f3063d 100644 (file)
--- a/tests/error_expr_not_ok.nit
+++ b/tests/error_expr_not_ok.nit
@@ -35,7 +35,7 @@ fun trash(x: A) do end
 #alt4#var fail: Object = 5
 #alt5#var fail: Object = 5
 #alt5#fail = fail2(5)
-
+#alt6#var fail = null
 var ok = 5
 ok.fail
 var nok: Int = fail

diff --git a/tests/sav/base_var_null.sav b/tests/sav/base_var_null.sav
new file mode 100644 (file)
index 0000000..6ed281c
--- /dev/null
+++ b/tests/sav/base_var_null.sav
@@ -0,0 +1,2 @@
+1
+1

diff --git a/tests/sav/base_var_null_alt1.sav b/tests/sav/base_var_null_alt1.sav
new file mode 100644 (file)
index 0000000..c8c8406
--- /dev/null
+++ b/tests/sav/base_var_null_alt1.sav
@@ -0,0 +1 @@
+alt/base_var_null_alt1.nit:28,1--8: Error: Method 'output' call on 'null'.

diff --git a/tests/sav/base_var_null_alt2.sav b/tests/sav/base_var_null_alt2.sav
new file mode 100644 (file)
index 0000000..0823d6c
--- /dev/null
+++ b/tests/sav/base_var_null_alt2.sav
@@ -0,0 +1 @@
+alt/base_var_null_alt2.nit:29,1--6: Error: Attribute '_foo' access on 'null'.

diff --git a/tests/sav/base_var_null_alt3.sav b/tests/sav/base_var_null_alt3.sav
new file mode 100644 (file)
index 0000000..2ec4755
--- /dev/null
+++ b/tests/sav/base_var_null_alt3.sav
@@ -0,0 +1 @@
+alt/base_var_null_alt3.nit:30,1--10: Error: Attribute '_foo' access on 'null'.

diff --git a/tests/sav/base_var_null_alt4.sav b/tests/sav/base_var_null_alt4.sav
new file mode 100644 (file)
index 0000000..938ba6c
--- /dev/null
+++ b/tests/sav/base_var_null_alt4.sav
@@ -0,0 +1 @@
+alt/base_var_null_alt4.nit:31,1--6: Error: Method '+' call on 'null'.

diff --git a/tests/sav/base_var_null_alt5.sav b/tests/sav/base_var_null_alt5.sav
new file mode 100644 (file)
index 0000000..9d77dc0
--- /dev/null
+++ b/tests/sav/base_var_null_alt5.sav
@@ -0,0 +1 @@
+alt/base_var_null_alt5.nit:35,1--8: Error: Method 'output' call on 'null'.

diff --git a/tests/sav/base_var_null_alt6.sav b/tests/sav/base_var_null_alt6.sav
new file mode 100644 (file)
index 0000000..cdb337a
--- /dev/null
+++ b/tests/sav/base_var_null_alt6.sav
@@ -0,0 +1 @@
+alt/base_var_null_alt6.nit:36,1--6: Error: Attribute '_foo' access on 'null'.

diff --git a/tests/sav/base_var_null_alt7.sav b/tests/sav/base_var_null_alt7.sav
new file mode 100644 (file)
index 0000000..9cdfcb8
--- /dev/null
+++ b/tests/sav/base_var_null_alt7.sav
@@ -0,0 +1 @@
+alt/base_var_null_alt7.nit:37,1--10: Error: Attribute '_foo' access on 'null'.

diff --git a/tests/sav/base_var_null_alt8.sav b/tests/sav/base_var_null_alt8.sav
new file mode 100644 (file)
index 0000000..df4597f
--- /dev/null
+++ b/tests/sav/base_var_null_alt8.sav
@@ -0,0 +1 @@
+alt/base_var_null_alt8.nit:38,1--6: Error: Method '+' call on 'null'.

diff --git a/tests/sav/error_expr_not_ok_alt6.sav b/tests/sav/error_expr_not_ok_alt6.sav
new file mode 100644 (file)
index 0000000..0249e8c
--- /dev/null
+++ b/tests/sav/error_expr_not_ok_alt6.sav
@@ -0,0 +1,123 @@
+alt/error_expr_not_ok_alt6.nit:19,19--22: Error: Method or variable 'fail' unknown in A.
+alt/error_expr_not_ok_alt6.nit:21,11--14: Error: Method or variable 'fail' unknown in A.
+alt/error_expr_not_ok_alt6.nit:22,26--29: Error: Method or variable 'fail' unknown in A.
+alt/error_expr_not_ok_alt6.nit:24,8--11: Error: Method or variable 'fail' unknown in A.
+alt/error_expr_not_ok_alt6.nit:25,9--12: Error: Method or variable 'fail' unknown in A.
+alt/error_expr_not_ok_alt6.nit:40,1--7: Error: Method 'fail' doesn't exists in Int.
+alt/error_expr_not_ok_alt6.nit:41,16--19: Type error: expected Int, got null
+alt/error_expr_not_ok_alt6.nit:42,7--9: Type error: expected A, got Int
+alt/error_expr_not_ok_alt6.nit:43,1--8: Error: Method 'fail' doesn't exists in Int.
+alt/error_expr_not_ok_alt6.nit:45,7--10: Type error: expected A, got null
+alt/error_expr_not_ok_alt6.nit:46,1--9: Error: Method 'fail' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:49,7--10: Type error: expected A, got null
+alt/error_expr_not_ok_alt6.nit:50,1--10: Error: Method 'trash' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:51,8--9: Type error: expected null, got Int
+alt/error_expr_not_ok_alt6.nit:52,6--9: Type error: expected Int, got null
+alt/error_expr_not_ok_alt6.nit:53,1--9: Error: Method '+' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:54,7--10: Type error: expected Int, got null
+alt/error_expr_not_ok_alt6.nit:55,1--12: Error: Method '+' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:60,4--7: Type error: expected Bool, got null
+alt/error_expr_not_ok_alt6.nit:60,20: Type error: expected A, got Int
+alt/error_expr_not_ok_alt6.nit:62,10--13: Type error: expected Bool, got null
+alt/error_expr_not_ok_alt6.nit:62,7--27: Type error: expected A, got Int
+alt/error_expr_not_ok_alt6.nit:63,7--30: Type error: expected A, got nullable Int
+alt/error_expr_not_ok_alt6.nit:64,7--33: Type error: expected A, got null
+alt/error_expr_not_ok_alt6.nit:66,7--10: Type error: expected Bool, got null
+alt/error_expr_not_ok_alt6.nit:66,21: Type error: expected A, got Int
+alt/error_expr_not_ok_alt6.nit:69,10--13: Type error: expected Collection[nullable Object], got null
+alt/error_expr_not_ok_alt6.nit:71,8--11: Type error: expected Bool, got null
+alt/error_expr_not_ok_alt6.nit:72,7--15: Type error: expected A, got null
+alt/error_expr_not_ok_alt6.nit:73,7--10: Type error: expected Bool, got null
+alt/error_expr_not_ok_alt6.nit:73,7--18: Type error: expected A, got Bool
+alt/error_expr_not_ok_alt6.nit:74,15--18: Type error: expected Bool, got null
+alt/error_expr_not_ok_alt6.nit:74,7--18: Type error: expected A, got Bool
+alt/error_expr_not_ok_alt6.nit:75,7--10: Type error: expected Bool, got null
+alt/error_expr_not_ok_alt6.nit:75,15--18: Type error: expected Bool, got null
+alt/error_expr_not_ok_alt6.nit:75,7--18: Type error: expected A, got Bool
+alt/error_expr_not_ok_alt6.nit:76,7--10: Type error: expected Bool, got null
+alt/error_expr_not_ok_alt6.nit:76,7--19: Type error: expected A, got Bool
+alt/error_expr_not_ok_alt6.nit:77,7--10: Type error: expected Bool, got null
+alt/error_expr_not_ok_alt6.nit:77,16--19: Type error: expected Bool, got null
+alt/error_expr_not_ok_alt6.nit:77,7--19: Type error: expected A, got Bool
+alt/error_expr_not_ok_alt6.nit:78,7--10: Type error: expected Bool, got null
+alt/error_expr_not_ok_alt6.nit:78,16--19: Type error: expected Bool, got null
+alt/error_expr_not_ok_alt6.nit:78,7--19: Type error: expected A, got Bool
+alt/error_expr_not_ok_alt6.nit:79,11--14: Type error: expected Bool, got null
+alt/error_expr_not_ok_alt6.nit:79,7--14: Type error: expected A, got Bool
+alt/error_expr_not_ok_alt6.nit:80,7--15: Error: Method '==' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:81,7--15: Type error: expected A, got Bool
+alt/error_expr_not_ok_alt6.nit:82,7--18: Error: Method '==' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:83,7--15: Error: Method '!=' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:84,7--15: Type error: expected A, got Bool
+alt/error_expr_not_ok_alt6.nit:85,7--18: Error: Method '!=' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:86,7--15: Type error: expected A, got Bool
+alt/error_expr_not_ok_alt6.nit:87,7--15: Type error: expected A, got Bool
+alt/error_expr_not_ok_alt6.nit:88,7--18: Type error: expected A, got Bool
+alt/error_expr_not_ok_alt6.nit:89,7--14: Error: Method '<' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:90,11--14: Type error: expected Int, got null
+alt/error_expr_not_ok_alt6.nit:90,7--14: Type error: expected A, got Bool
+alt/error_expr_not_ok_alt6.nit:91,7--17: Error: Method '<' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:92,7--14: Error: Method '>' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:93,11--14: Type error: expected Int, got null
+alt/error_expr_not_ok_alt6.nit:93,7--14: Type error: expected A, got Bool
+alt/error_expr_not_ok_alt6.nit:94,7--17: Error: Method '>' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:95,7--15: Error: Method '<=' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:96,12--15: Type error: expected Int, got null
+alt/error_expr_not_ok_alt6.nit:96,7--15: Type error: expected A, got Bool
+alt/error_expr_not_ok_alt6.nit:97,7--18: Error: Method '<=' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:98,7--15: Error: Method '>=' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:99,12--15: Type error: expected Int, got null
+alt/error_expr_not_ok_alt6.nit:99,7--15: Type error: expected A, got Bool
+alt/error_expr_not_ok_alt6.nit:100,7--18: Error: Method '>=' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:101,7--16: Error: Method '<=>' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:102,13--16: Type error: expected Int, got null
+alt/error_expr_not_ok_alt6.nit:102,7--16: Type error: expected A, got Int
+alt/error_expr_not_ok_alt6.nit:103,7--19: Error: Method '<=>' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:104,7--14: Error: Method '+' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:105,11--14: Type error: expected Int, got null
+alt/error_expr_not_ok_alt6.nit:105,7--14: Type error: expected A, got Int
+alt/error_expr_not_ok_alt6.nit:106,7--17: Error: Method '+' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:107,7--14: Error: Method '-' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:108,11--14: Type error: expected Int, got null
+alt/error_expr_not_ok_alt6.nit:108,7--14: Type error: expected A, got Int
+alt/error_expr_not_ok_alt6.nit:109,7--17: Error: Method '-' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:110,7--14: Error: Method '*' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:111,11--14: Type error: expected Int, got null
+alt/error_expr_not_ok_alt6.nit:111,7--14: Type error: expected A, got Int
+alt/error_expr_not_ok_alt6.nit:112,7--17: Error: Method '*' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:113,7--14: Error: Method '/' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:114,11--14: Type error: expected Int, got null
+alt/error_expr_not_ok_alt6.nit:114,7--14: Type error: expected A, got Int
+alt/error_expr_not_ok_alt6.nit:115,7--17: Error: Method '/' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:116,7--14: Error: Method '%' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:117,11--14: Type error: expected Int, got null
+alt/error_expr_not_ok_alt6.nit:117,7--14: Type error: expected A, got Int
+alt/error_expr_not_ok_alt6.nit:118,7--17: Error: Method '%' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:119,7--11: Error: Method 'unary -' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:122,7--15: Error: Attribute _fail doesn't exists in String.
+alt/error_expr_not_ok_alt6.nit:123,1--13: Error: Attribute _fail doesn't exists in String.
+alt/error_expr_not_ok_alt6.nit:124,1--14: Error: Attribute _fail doesn't exists in String.
+alt/error_expr_not_ok_alt6.nit:126,7--13: Error: Attribute '_x' access on 'null'.
+alt/error_expr_not_ok_alt6.nit:127,1--11: Error: Attribute '_x' access on 'null'.
+alt/error_expr_not_ok_alt6.nit:128,1--12: Error: Attribute '_x' access on 'null'.
+alt/error_expr_not_ok_alt6.nit:131,11--14: Type error: expected Int, got null
+alt/error_expr_not_ok_alt6.nit:131,7--14: Type error: expected A, got Int
+alt/error_expr_not_ok_alt6.nit:132,10--13: Type error: expected Int, got null
+alt/error_expr_not_ok_alt6.nit:133,11--14: Type error: expected Int, got null
+alt/error_expr_not_ok_alt6.nit:134,7--12: Error: Method '[]' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:135,1--11: Error: Method '[]=' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:136,1--12: Error: Method '[]' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:137,1--17: Error: Method '[]=' call on 'null'.
+alt/error_expr_not_ok_alt6.nit:139,8--14: Type error: Int incompatible with null.
+alt/error_expr_not_ok_alt6.nit:140,8--14: Type error: null incompatible with Int.
+alt/error_expr_not_ok_alt6.nit:141,8--11: Type error: expected Discrete, got null
+alt/error_expr_not_ok_alt6.nit:142,8--14: Type error: Int incompatible with null.
+alt/error_expr_not_ok_alt6.nit:143,8--14: Type error: null incompatible with Int.
+alt/error_expr_not_ok_alt6.nit:144,8--11: Type error: expected Discrete, got null
+alt/error_expr_not_ok_alt6.nit:145,8--14: Type error: expected A, got Array[nullable Int]
+alt/error_expr_not_ok_alt6.nit:146,8--14: Type error: expected A, got Array[nullable Int]
+alt/error_expr_not_ok_alt6.nit:147,8--17: Type error: expected A, got Array[null]
+alt/error_expr_not_ok_alt6.nit:149,7--24: Type error: expected A, got String
+alt/error_expr_not_ok_alt6.nit:150,7--17: Type error: expected A, got Int
+alt/error_expr_not_ok_alt6.nit:151,7--10: Type error: 'as(not null)' on 'null' value.
+alt/error_expr_not_ok_alt6.nit:152,7--18: Type error: expected A, got Bool