Merge: Warn useless do block

Warn useless do block, like

~~~nit
loop do
  print 1
end
~~~

Close #1437

Pull-Request: #1438
Reviewed-by: Romain Chanoir <chanoir.romain@courrier.uqam.ca>
Reviewed-by: Lucas Bajolet <r4pass@hotmail.com>
Reviewed-by: Alexandre Terrasa <alexandre@moz-code.org>

diff --git a/src/frontend/simple_misc_analysis.nit b/src/frontend/simple_misc_analysis.nit
index 885d794..f61b10a 100644 (file)
--- a/src/frontend/simple_misc_analysis.nit
+++ b/src/frontend/simple_misc_analysis.nit
@@ -65,6 +65,14 @@ private class SimpleMiscVisitor
        do
                toolcontext.warning(node.hot_location, tag, msg)
        end
+
+       # Issue a warning if `sub` is a standalone `do` block.
+       fun check_do_expr(sub: nullable AExpr)
+       do
+               if sub isa ADoExpr then
+                       warning(sub, "useless-do", "Warning: superfluous `do` block.")
+               end
+       end
 end
 
 
@@ -143,6 +151,21 @@ redef class AWhileExpr
                else
                        n_expr.warn_parentheses(v)
                end
+               v.check_do_expr(n_block)
+       end
+end
+
+redef class ADoExpr
+       redef fun after_simple_misc(v)
+       do
+               v.check_do_expr(n_block)
+       end
+end
+
+redef class ALoopExpr
+       redef fun after_simple_misc(v)
+       do
+               v.check_do_expr(n_block)
        end
 end
 
@@ -150,6 +173,14 @@ redef class AForExpr
        redef fun after_simple_misc(v)
        do
                n_expr.warn_parentheses(v)
+               v.check_do_expr(n_block)
+       end
+end
+
+redef class AWithExpr
+       redef fun after_simple_misc(v)
+       do
+               v.check_do_expr(n_block)
        end
 end
 

diff --git a/tests/base_do_block.nit b/tests/base_do_block.nit
new file mode 100644 (file)
index 0000000..b9fdad4
--- /dev/null
+++ b/tests/base_do_block.nit
@@ -0,0 +1,41 @@
+# This file is part of NIT ( http://www.nitlanguage.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.
+
+class Foo
+       fun start do end
+       fun finish do end
+end
+fun foo: Foo do return new Foo
+
+do do
+       1.output
+end
+while false do do
+       2.output
+end
+if true then do
+       3.output
+end else do
+       4.output
+end
+for i in [0..1] do do
+       5.output
+end
+with foo do do
+       6.output
+end
+loop do
+       7.output
+       return
+end

diff --git a/tests/sav/base_do_block.res b/tests/sav/base_do_block.res
new file mode 100644 (file)
index 0000000..f99d451
--- /dev/null
+++ b/tests/sav/base_do_block.res
@@ -0,0 +1,11 @@
+base_do_block.nit:21,4--23,3: Warning: superfluous `do` block.
+base_do_block.nit:24,16--26,3: Warning: superfluous `do` block.
+base_do_block.nit:32,20--34,3: Warning: superfluous `do` block.
+base_do_block.nit:35,13--37,3: Warning: superfluous `do` block.
+base_do_block.nit:38,6--41,3: Warning: superfluous `do` block.
+1
+3
+5
+5
+6
+7