PY-71549 Move async-related check from PyKeywordHighlightingAnnotator to PyAsyncAwaitAnnotatorVisitor

It also caused double highlighting on the frontend as PyKeywordHighlightingAnnotator is currently registered in both frontend and backend.

GitOrigin-RevId: cdf111acfdb8a979613007e12abcf6c7dac9c9dd

python/python-psi-impl/resources/messages/PyPsiBundle.properties

@@ -170,6 +170,7 @@ ANN.continue.break.or.return.in.star.except='break', 'continue' and 'return' can
 ANN.await.outside.async.function='await' outside async function
 ANN.async.with.outside.function='async with' outside async function
 ANN.async.for.outside.function='async for' outside async function
+ANN.function.cannot.be.async=function \"{0}\" cannot be async
 QFIX.convert.into.async.function=Convert to async function
 
 ### quick doc generator

python/python-psi-impl/src/com/jetbrains/python/validation/PyAsyncAwaitAnnotatorVisitor.java

@@ -8,12 +8,15 @@ import com.intellij.modcommand.ModPsiUpdater;
 import com.intellij.modcommand.PsiUpdateModCommandAction;
 import com.intellij.psi.PsiElement;
 import com.jetbrains.python.PyPsiBundle;
+import com.jetbrains.python.PySyntaxCoreBundle;
 import com.jetbrains.python.PyTokenTypes;
 import com.jetbrains.python.codeInsight.controlflow.ScopeOwner;
 import com.jetbrains.python.codeInsight.dataflow.scope.ScopeUtil;
 import com.jetbrains.python.psi.*;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.Optional;
+
 public final class PyAsyncAwaitAnnotatorVisitor extends PyElementVisitor {
   private final @NotNull PyAnnotationHolder myHolder;
 
@@ -102,6 +105,18 @@ public final class PyAsyncAwaitAnnotatorVisitor extends PyElementVisitor {
     checkComprehension(node);
   }
 
+  @Override
+  public void visitPyFunction(@NotNull PyFunction node) {
+    if (!node.isAsyncAllowed()) {
+      Optional
+        .ofNullable(node.getNode())
+        .map(astNode -> astNode.findChildByType(PyTokenTypes.ASYNC_KEYWORD))
+        .ifPresent(asyncNode -> myHolder.newAnnotation(HighlightSeverity.ERROR,
+                                                       PyPsiBundle.message("ANN.function.cannot.be.async", node.getName()))
+          .range(asyncNode).create());
+    }
+  }
+
   private static class ConvertIntoAsyncFunctionFix extends PsiUpdateModCommandAction<PyFunction> {
     protected ConvertIntoAsyncFunctionFix(@NotNull PyFunction element) {
       super(element);

python/python-syntax-core/resources/messages/PySyntaxCoreBundle.properties

@@ -1,6 +1,3 @@
-### Annotators ###
-ANN.function.cannot.be.async=function \"{0}\" cannot be async
-
 ### Formatter
 formatter.panel.dict.alignment.do.not.align=Do not align
 formatter.panel.dict.alignment.align.on.colon=Align on colon

python/python-syntax-core/src/com/jetbrains/python/validation/PyKeywordHighlightingAnnotator.java

@@ -55,14 +55,6 @@ public final class PyKeywordHighlightingAnnotator extends PyAnnotatorBase implem
       if (node.isAsyncAllowed()) {
         highlightKeyword(node, PyTokenTypes.ASYNC_KEYWORD);
       }
-      else {
-        Optional
-          .ofNullable(node.getNode())
-          .map(astNode -> astNode.findChildByType(PyTokenTypes.ASYNC_KEYWORD))
-          .ifPresent(asyncNode -> myHolder.newAnnotation(HighlightSeverity.ERROR,
-                                                         PySyntaxCoreBundle.message("ANN.function.cannot.be.async", node.getName()))
-            .range(asyncNode).create());
-      }
     }
 
     @Override