Do constant folding for match variables

Summary: With the removal of the constant folding pass match variables are no longer working when they're in the form `-1` or `1 + 3j`. This adds them back in so patterns work.

Reviewed By: jbower-fb

Differential Revision: D81961225

fbshipit-source-id: c843e571a68ad8218d61048f299363a9d59ee4fb

Author: DinoV

cinderx/PythonLib/cinderx/compiler/optimizer.py

@@ -509,6 +509,28 @@ def visitBinOp(self, node: ast.BinOp) -> ast.expr:
 
         return self.update_node(node, left=lhs, right=rhs)
 
+    def visitMatchValue(self, node: ast.MatchValue) -> ast.MatchValue:
+        return self.update_node(node, value=self.fold_const_match_patterns(node.value))
+
+    def visitMatchMapping(self, node: ast.MatchMapping) -> ast.MatchMapping:
+        keys = [self.fold_const_match_patterns(key) for key in node.keys]
+        patterns = self.walk_list(node.patterns)
+        return self.update_node(node, keys=keys, patterns=patterns)
+
+    def fold_const_match_patterns(self, node: ast.expr) -> ast.expr:
+        if isinstance(node, ast.UnaryOp):
+            if isinstance(node.op, ast.USub) and isinstance(node.operand, ast.Constant):
+                return super().visitUnaryOp(node)
+        elif isinstance(node, ast.BinOp) and isinstance(node.op, (ast.Add, ast.Sub)):
+            if isinstance(node.right, ast.Constant):
+                node = self.update_node(
+                    node, left=self.fold_const_match_patterns(node.left)
+                )
+                if isinstance(node.left, ast.Constant):
+                    return super().visitBinOp(node)
+
+        return node
+
     def visitTuple(self, node: ast.Tuple) -> ast.expr:
         elts = self.walk_list(node.elts)
 

cinderx/PythonLib/test_cinderx/test_compiler/testcorpus/85_match_unary_binary_op.py

@@ -0,0 +1,7 @@
+match x:
+    case 0 + 0j:
+        y = 0
+
+match x:
+    case -1:
+        y = 0