From d996815820925d3047d829d9015764cd6e8b0bd5 Mon Sep 17 00:00:00 2001
From: Tyson Andre <tysonandre775@hotmail.com>
Date: Sun, 11 Feb 2018 21:29:26 -0800
Subject: [PATCH] For #19: Fix an edge case parsing `=` and `instanceof`

This does not fix every single edge case.
This only fixes the edge cases for unary operators
on the left hand side of binary operators expecting a variable.

(That probably isn't even every single binary operator or unary operator)
---
 src/Parser.php                           | 31 +++++++++-
 tests/cases/parser/lhsVariable1.php      |  3 +
 tests/cases/parser/lhsVariable1.php.diag |  1 +
 tests/cases/parser/lhsVariable1.php.tree | 77 ++++++++++++++++++++++++
 tests/cases/parser/lhsVariable2.php      |  3 +
 tests/cases/parser/lhsVariable2.php.diag |  1 +
 tests/cases/parser/lhsVariable2.php.tree | 76 +++++++++++++++++++++++
 tests/cases/parser/lhsVariable3.php      |  3 +
 tests/cases/parser/lhsVariable3.php.diag |  1 +
 tests/cases/parser/lhsVariable3.php.tree | 76 +++++++++++++++++++++++
 tests/cases/parser/lhsVariable4.php      |  3 +
 tests/cases/parser/lhsVariable4.php.diag |  1 +
 tests/cases/parser/lhsVariable4.php.tree | 76 +++++++++++++++++++++++
 13 files changed, 350 insertions(+), 2 deletions(-)
 create mode 100644 tests/cases/parser/lhsVariable1.php
 create mode 100644 tests/cases/parser/lhsVariable1.php.diag
 create mode 100644 tests/cases/parser/lhsVariable1.php.tree
 create mode 100644 tests/cases/parser/lhsVariable2.php
 create mode 100644 tests/cases/parser/lhsVariable2.php.diag
 create mode 100644 tests/cases/parser/lhsVariable2.php.tree
 create mode 100644 tests/cases/parser/lhsVariable3.php
 create mode 100644 tests/cases/parser/lhsVariable3.php.diag
 create mode 100644 tests/cases/parser/lhsVariable3.php.tree
 create mode 100644 tests/cases/parser/lhsVariable4.php
 create mode 100644 tests/cases/parser/lhsVariable4.php.diag
 create mode 100644 tests/cases/parser/lhsVariable4.php.tree

diff --git a/src/Parser.php b/src/Parser.php
index 7aeece9..7c1b4af 100644
--- a/src/Parser.php
+++ b/src/Parser.php
@@ -1664,8 +1664,35 @@ class Parser {
             //
             // After we finish building the BinaryExpression, we rebuild the UnaryExpression so that it includes
             // the original operator, and the newly constructed exponentiation-expression as the operand.
-            $shouldOperatorTakePrecedenceOverUnary =
-                $token->kind === TokenKind::AsteriskAsteriskToken && $leftOperand instanceof UnaryExpression;
+            $shouldOperatorTakePrecedenceOverUnary = false;
+            switch ($token->kind) {
+                case TokenKind::AsteriskAsteriskToken:
+                    $shouldOperatorTakePrecedenceOverUnary = $leftOperand instanceof UnaryExpression;
+                    break;
+                case TokenKind::EqualsToken:
+                case TokenKind::AsteriskAsteriskEqualsToken:
+                case TokenKind::AsteriskEqualsToken:
+                case TokenKind::SlashEqualsToken:
+                case TokenKind::PercentEqualsToken:
+                case TokenKind::PlusEqualsToken:
+                case TokenKind::MinusEqualsToken:
+                case TokenKind::DotEqualsToken:
+                case TokenKind::LessThanLessThanEqualsToken:
+                case TokenKind::GreaterThanGreaterThanEqualsToken:
+                case TokenKind::AmpersandEqualsToken:
+                case TokenKind::CaretEqualsToken:
+                case TokenKind::BarEqualsToken:
+                case TokenKind::InstanceOfKeyword:
+                    // Workarounds for https://github.com/Microsoft/tolerant-php-parser/issues/19#issue-201714377
+                    // Parse `!$a = $b` as `!($a = $b)` - PHP constrains the Left Hand Side of an assignment to a variable. A unary operator (`@`, `!`, etc.) is not a variable.
+                    // Instanceof has similar constraints for the LHS.
+                    // So does `!$a += $b`
+                    // TODO: Any other operators?
+                    if ($leftOperand instanceof UnaryOpExpression) {
+                        $shouldOperatorTakePrecedenceOverUnary = true;
+                    }
+                    break;
+            }
 
             if ($shouldOperatorTakePrecedenceOverUnary) {
                 $unaryExpression = $leftOperand;
diff --git a/tests/cases/parser/lhsVariable1.php b/tests/cases/parser/lhsVariable1.php
new file mode 100644
index 0000000..1b6b58f
--- /dev/null
+++ b/tests/cases/parser/lhsVariable1.php
@@ -0,0 +1,3 @@
+<?php
+
+echo ~$b = $c;
diff --git a/tests/cases/parser/lhsVariable1.php.diag b/tests/cases/parser/lhsVariable1.php.diag
new file mode 100644
index 0000000..0637a08
--- /dev/null
+++ b/tests/cases/parser/lhsVariable1.php.diag
@@ -0,0 +1 @@
+[]
\ No newline at end of file
diff --git a/tests/cases/parser/lhsVariable1.php.tree b/tests/cases/parser/lhsVariable1.php.tree
new file mode 100644
index 0000000..ddfebf4
--- /dev/null
+++ b/tests/cases/parser/lhsVariable1.php.tree
@@ -0,0 +1,77 @@
+{
+    "SourceFileNode": {
+        "statementList": [
+            {
+                "InlineHtml": {
+                    "scriptSectionEndTag": null,
+                    "text": null,
+                    "scriptSectionStartTag": {
+                        "kind": "ScriptSectionStartTag",
+                        "textLength": 6
+                    }
+                }
+            },
+            {
+                "ExpressionStatement": {
+                    "expression": {
+                        "EchoExpression": {
+                            "echoKeyword": {
+                                "kind": "EchoKeyword",
+                                "textLength": 4
+                            },
+                            "expressions": {
+                                "ExpressionList": {
+                                    "children": [
+                                        {
+                                            "UnaryOpExpression": {
+                                                "operator": {
+                                                    "kind": "TildeToken",
+                                                    "textLength": 1
+                                                },
+                                                "operand": {
+                                                    "AssignmentExpression": {
+                                                        "leftOperand": {
+                                                            "Variable": {
+                                                                "dollar": null,
+                                                                "name": {
+                                                                    "kind": "VariableName",
+                                                                    "textLength": 2
+                                                                }
+                                                            }
+                                                        },
+                                                        "operator": {
+                                                            "kind": "EqualsToken",
+                                                            "textLength": 1
+                                                        },
+                                                        "byRef": null,
+                                                        "rightOperand": {
+                                                            "Variable": {
+                                                                "dollar": null,
+                                                                "name": {
+                                                                    "kind": "VariableName",
+                                                                    "textLength": 2
+                                                                }
+                                                            }
+                                                        }
+                                                    }
+                                                }
+                                            }
+                                        }
+                                    ]
+                                }
+                            }
+                        }
+                    },
+                    "semicolon": {
+                        "kind": "SemicolonToken",
+                        "textLength": 1
+                    }
+                }
+            }
+        ],
+        "endOfFileToken": {
+            "kind": "EndOfFileToken",
+            "textLength": 0
+        }
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/parser/lhsVariable2.php b/tests/cases/parser/lhsVariable2.php
new file mode 100644
index 0000000..9d9239d
--- /dev/null
+++ b/tests/cases/parser/lhsVariable2.php
@@ -0,0 +1,3 @@
+<?php
+
+echo !$b += $c;
diff --git a/tests/cases/parser/lhsVariable2.php.diag b/tests/cases/parser/lhsVariable2.php.diag
new file mode 100644
index 0000000..0637a08
--- /dev/null
+++ b/tests/cases/parser/lhsVariable2.php.diag
@@ -0,0 +1 @@
+[]
\ No newline at end of file
diff --git a/tests/cases/parser/lhsVariable2.php.tree b/tests/cases/parser/lhsVariable2.php.tree
new file mode 100644
index 0000000..a96ff42
--- /dev/null
+++ b/tests/cases/parser/lhsVariable2.php.tree
@@ -0,0 +1,76 @@
+{
+    "SourceFileNode": {
+        "statementList": [
+            {
+                "InlineHtml": {
+                    "scriptSectionEndTag": null,
+                    "text": null,
+                    "scriptSectionStartTag": {
+                        "kind": "ScriptSectionStartTag",
+                        "textLength": 6
+                    }
+                }
+            },
+            {
+                "ExpressionStatement": {
+                    "expression": {
+                        "EchoExpression": {
+                            "echoKeyword": {
+                                "kind": "EchoKeyword",
+                                "textLength": 4
+                            },
+                            "expressions": {
+                                "ExpressionList": {
+                                    "children": [
+                                        {
+                                            "UnaryOpExpression": {
+                                                "operator": {
+                                                    "kind": "ExclamationToken",
+                                                    "textLength": 1
+                                                },
+                                                "operand": {
+                                                    "BinaryExpression": {
+                                                        "leftOperand": {
+                                                            "Variable": {
+                                                                "dollar": null,
+                                                                "name": {
+                                                                    "kind": "VariableName",
+                                                                    "textLength": 2
+                                                                }
+                                                            }
+                                                        },
+                                                        "operator": {
+                                                            "kind": "PlusEqualsToken",
+                                                            "textLength": 2
+                                                        },
+                                                        "rightOperand": {
+                                                            "Variable": {
+                                                                "dollar": null,
+                                                                "name": {
+                                                                    "kind": "VariableName",
+                                                                    "textLength": 2
+                                                                }
+                                                            }
+                                                        }
+                                                    }
+                                                }
+                                            }
+                                        }
+                                    ]
+                                }
+                            }
+                        }
+                    },
+                    "semicolon": {
+                        "kind": "SemicolonToken",
+                        "textLength": 1
+                    }
+                }
+            }
+        ],
+        "endOfFileToken": {
+            "kind": "EndOfFileToken",
+            "textLength": 0
+        }
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/parser/lhsVariable3.php b/tests/cases/parser/lhsVariable3.php
new file mode 100644
index 0000000..89e108b
--- /dev/null
+++ b/tests/cases/parser/lhsVariable3.php
@@ -0,0 +1,3 @@
+<?php
+
+echo !$b instanceof $c;
diff --git a/tests/cases/parser/lhsVariable3.php.diag b/tests/cases/parser/lhsVariable3.php.diag
new file mode 100644
index 0000000..0637a08
--- /dev/null
+++ b/tests/cases/parser/lhsVariable3.php.diag
@@ -0,0 +1 @@
+[]
\ No newline at end of file
diff --git a/tests/cases/parser/lhsVariable3.php.tree b/tests/cases/parser/lhsVariable3.php.tree
new file mode 100644
index 0000000..8b3aa6d
--- /dev/null
+++ b/tests/cases/parser/lhsVariable3.php.tree
@@ -0,0 +1,76 @@
+{
+    "SourceFileNode": {
+        "statementList": [
+            {
+                "InlineHtml": {
+                    "scriptSectionEndTag": null,
+                    "text": null,
+                    "scriptSectionStartTag": {
+                        "kind": "ScriptSectionStartTag",
+                        "textLength": 6
+                    }
+                }
+            },
+            {
+                "ExpressionStatement": {
+                    "expression": {
+                        "EchoExpression": {
+                            "echoKeyword": {
+                                "kind": "EchoKeyword",
+                                "textLength": 4
+                            },
+                            "expressions": {
+                                "ExpressionList": {
+                                    "children": [
+                                        {
+                                            "UnaryOpExpression": {
+                                                "operator": {
+                                                    "kind": "ExclamationToken",
+                                                    "textLength": 1
+                                                },
+                                                "operand": {
+                                                    "BinaryExpression": {
+                                                        "leftOperand": {
+                                                            "Variable": {
+                                                                "dollar": null,
+                                                                "name": {
+                                                                    "kind": "VariableName",
+                                                                    "textLength": 2
+                                                                }
+                                                            }
+                                                        },
+                                                        "operator": {
+                                                            "kind": "InstanceOfKeyword",
+                                                            "textLength": 10
+                                                        },
+                                                        "rightOperand": {
+                                                            "Variable": {
+                                                                "dollar": null,
+                                                                "name": {
+                                                                    "kind": "VariableName",
+                                                                    "textLength": 2
+                                                                }
+                                                            }
+                                                        }
+                                                    }
+                                                }
+                                            }
+                                        }
+                                    ]
+                                }
+                            }
+                        }
+                    },
+                    "semicolon": {
+                        "kind": "SemicolonToken",
+                        "textLength": 1
+                    }
+                }
+            }
+        ],
+        "endOfFileToken": {
+            "kind": "EndOfFileToken",
+            "textLength": 0
+        }
+    }
+}
\ No newline at end of file
diff --git a/tests/cases/parser/lhsVariable4.php b/tests/cases/parser/lhsVariable4.php
new file mode 100644
index 0000000..9d53bf4
--- /dev/null
+++ b/tests/cases/parser/lhsVariable4.php
@@ -0,0 +1,3 @@
+<?php
+
+echo -$b ^= $c;
diff --git a/tests/cases/parser/lhsVariable4.php.diag b/tests/cases/parser/lhsVariable4.php.diag
new file mode 100644
index 0000000..0637a08
--- /dev/null
+++ b/tests/cases/parser/lhsVariable4.php.diag
@@ -0,0 +1 @@
+[]
\ No newline at end of file
diff --git a/tests/cases/parser/lhsVariable4.php.tree b/tests/cases/parser/lhsVariable4.php.tree
new file mode 100644
index 0000000..399bc3d
--- /dev/null
+++ b/tests/cases/parser/lhsVariable4.php.tree
@@ -0,0 +1,76 @@
+{
+    "SourceFileNode": {
+        "statementList": [
+            {
+                "InlineHtml": {
+                    "scriptSectionEndTag": null,
+                    "text": null,
+                    "scriptSectionStartTag": {
+                        "kind": "ScriptSectionStartTag",
+                        "textLength": 6
+                    }
+                }
+            },
+            {
+                "ExpressionStatement": {
+                    "expression": {
+                        "EchoExpression": {
+                            "echoKeyword": {
+                                "kind": "EchoKeyword",
+                                "textLength": 4
+                            },
+                            "expressions": {
+                                "ExpressionList": {
+                                    "children": [
+                                        {
+                                            "UnaryOpExpression": {
+                                                "operator": {
+                                                    "kind": "MinusToken",
+                                                    "textLength": 1
+                                                },
+                                                "operand": {
+                                                    "BinaryExpression": {
+                                                        "leftOperand": {
+                                                            "Variable": {
+                                                                "dollar": null,
+                                                                "name": {
+                                                                    "kind": "VariableName",
+                                                                    "textLength": 2
+                                                                }
+                                                            }
+                                                        },
+                                                        "operator": {
+                                                            "kind": "CaretEqualsToken",
+                                                            "textLength": 2
+                                                        },
+                                                        "rightOperand": {
+                                                            "Variable": {
+                                                                "dollar": null,
+                                                                "name": {
+                                                                    "kind": "VariableName",
+                                                                    "textLength": 2
+                                                                }
+                                                            }
+                                                        }
+                                                    }
+                                                }
+                                            }
+                                        }
+                                    ]
+                                }
+                            }
+                        }
+                    },
+                    "semicolon": {
+                        "kind": "SemicolonToken",
+                        "textLength": 1
+                    }
+                }
+            }
+        ],
+        "endOfFileToken": {
+            "kind": "EndOfFileToken",
+            "textLength": 0
+        }
+    }
+}
\ No newline at end of file