Improve source_mapping parsing for old solcs

slither/core/source_mapping/source_mapping.py

@@ -125,16 +125,7 @@ class SourceMapping(Context):
     @property
     def source_mapping_str(self):
 
-#        def relative_path(path):
-#            # Remove absolute path for printing
-#           # Truffle returns absolutePath
-#           splited_path = path.split(os.sep)
-#           if 'contracts' in splited_path:
-#               idx = splited_path.index('contracts')
-#               return os.sep.join(splited_path[idx-1:])
-#           return path
-
-        lines = self.source_mapping['lines']
+        lines = self.source_mapping.get('lines', None)
         if not lines:
             lines = ''
         elif len(lines) == 1:

slither/solc_parsing/slitherSolc.py

@@ -148,6 +148,14 @@ class SlitherSolc(Slither):
             sourceUnit = re.findall('[0-9]*:[0-9]*:([0-9]*)', data['src'])
             if len(sourceUnit) == 1:
                 sourceUnit = int(sourceUnit[0])
+        if sourceUnit == -1:
+            # if source unit is not found
+            # We can still deduce it, by assigning to the last source_code added
+            # This works only for crytic compile.
+            # which used --combined-json ast, rather than --ast-json
+            # As a result -1 is not used as index
+            if not self.crytic_compile is None:
+                sourceUnit = len(self.source_code)
 
         self._source_units[sourceUnit] = name
         if os.path.isfile(name) and not name in self.source_code: