don't parse compound statements after semicolon at top level of file (PY-7660)

python/src/com/jetbrains/python/parsing/ParsingScope.java

@@ -7,6 +7,7 @@ public class ParsingScope {
   private boolean myFunction = false;
   private boolean myClass = false;
   private boolean mySuite = false;
+  private boolean myAfterSemicolon = false;
 
   public ParsingScope withFunction(boolean flag) {
     final ParsingScope result = copy();
@@ -38,6 +39,14 @@ public class ParsingScope {
     return mySuite;
   }
 
+  public boolean isAfterSemicolon() {
+    return myAfterSemicolon;
+  }
+
+  public void setAfterSemicolon(boolean value) {
+    myAfterSemicolon = value;
+  }
+
   protected ParsingScope createInstance() {
     return new ParsingScope();
   }

python/src/com/jetbrains/python/parsing/PyParser.java

@@ -30,10 +30,18 @@ public class PyParser implements PsiParser {
     long start = System.currentTimeMillis();
     final PsiBuilder.Marker rootMarker = builder.mark();
     ParsingContext context = createParsingContext(builder, myLanguageLevel, myFutureFlag);
-    StatementParsing stmt_parser = context.getStatementParser();
-    builder.setTokenTypeRemapper(stmt_parser); // must be done before touching the caching lexer with eof() call.
+    StatementParsing statementParser = context.getStatementParser();
+    builder.setTokenTypeRemapper(statementParser); // must be done before touching the caching lexer with eof() call.
+    boolean lastAfterSemicolon = false;
     while (!builder.eof()) {
-      stmt_parser.parseStatement(context.emptyParsingScope());
+      ParsingScope scope = context.emptyParsingScope();
+      if (lastAfterSemicolon) {
+        statementParser.parseSimpleStatement(scope);
+      }
+      else {
+        statementParser.parseStatement(scope);
+      }
+      lastAfterSemicolon = scope.isAfterSemicolon();
     }
     rootMarker.done(root);
     ASTNode ast = builder.getTreeBuilt();

python/src/com/jetbrains/python/parsing/StatementParsing.java

@@ -254,8 +254,10 @@ public class StatementParsing extends Parsing implements ITokenTypeRemapper {
     else if (builder.getTokenType() == PyTokenTypes.SEMICOLON) {
       if (!scope.isSuite()) {
         builder.advanceLexer();
+        scope.setAfterSemicolon(true);
         if (builder.getTokenType() == PyTokenTypes.STATEMENT_BREAK) {
           builder.advanceLexer();
+          scope.setAfterSemicolon(false);
         }
       }
     }

python/testData/psi/CompoundStatementAfterSemicolon.py

@@ -0,0 +1,2 @@
+a = 0; if a:
+    pass

python/testData/psi/CompoundStatementAfterSemicolon.txt

@@ -0,0 +1,28 @@
+PyFile:CompoundStatementAfterSemicolon.py
+  PyAssignmentStatement
+    PyTargetExpression: a
+      PsiElement(Py:IDENTIFIER)('a')
+    PsiWhiteSpace(' ')
+    PsiElement(Py:EQ)('=')
+    PsiWhiteSpace(' ')
+    PyNumericLiteralExpression
+      PsiElement(Py:INTEGER_LITERAL)('0')
+    PsiElement(Py:SEMICOLON)(';')
+  PsiWhiteSpace(' ')
+  PsiElement(Py:IF_KEYWORD)('if')
+  PsiErrorElement:Statement expected, found Py:IF_KEYWORD
+    <empty list>
+  PsiWhiteSpace(' ')
+  PyExpressionStatement
+    PyReferenceExpression: a
+      PsiElement(Py:IDENTIFIER)('a')
+    PsiErrorElement:End of statement expected
+      <empty list>
+  PsiElement(Py:COLON)(':')
+  PsiErrorElement:Statement expected, found Py:COLON
+    <empty list>
+  PsiWhiteSpace('\n    ')
+  PsiErrorElement:Unexpected indent
+    <empty list>
+  PyPassStatement
+    PsiElement(Py:PASS_KEYWORD)('pass')

python/testSrc/com/jetbrains/python/PythonParsingTest.java

@@ -352,6 +352,9 @@ public class PythonParsingTest extends ParsingTestCase {
     doTest(LanguageLevel.PYTHON25);
   }
 
+  public void testCompoundStatementAfterSemicolon() {  // PY-7660
+    doTest();
+  }
 
   public void doTest(LanguageLevel languageLevel) {
     LanguageLevel prev = myLanguageLevel;