[parser] Make sure the isInputIncomplete() function works as expected for multi-line strings

Author: akyrtzi

lib/Parse/ParseExpr.cpp

@@ -1765,6 +1765,10 @@ ParserResult<Expr> Parser::parseExprPrimary(Diag<> ID, bool isExprBasic) {
   // Eat an invalid token in an expression context.  Error tokens are diagnosed
   // by the lexer, so there is no reason to emit another diagnostic.
   case tok::unknown:
+    if (Tok.getText().startswith("\"\"\"")) {
+      // This was due to unterminated multi-line string.
+      IsInputIncomplete = true;
+    }
     consumeToken(tok::unknown);
     return nullptr;
 

lib/Parse/ParseStmt.cpp

@@ -318,6 +318,10 @@ ParserStatus Parser::parseBraceItems(SmallVectorImpl<ASTNode> &Entries,
     // Eat invalid tokens instead of allowing them to produce downstream errors.
     if (Tok.is(tok::unknown)) {
       SyntaxParsingContext ErrContext(SyntaxContext, SyntaxContextKind::Stmt);
+      if (Tok.getText().startswith("\"\"\"")) {
+        // This was due to unterminated multi-line string.
+        IsInputIncomplete = true;
+      }
       consumeToken();
       continue;
     }

test/IDE/test-input-complete/Inputs/multi_line_string1.swift

@@ -0,0 +1,4 @@
+"""
+some
+multiline
+string

test/IDE/test-input-complete/Inputs/multi_line_string2.swift

@@ -0,0 +1,5 @@
+a +
+"""
+some
+multiline
+string

test/IDE/test-input-complete/Inputs/multi_line_string3.swift

@@ -0,0 +1,5 @@
+"""
+some
+multiline
+string
+\(

test/IDE/test-input-complete/test_input.swift

@@ -31,6 +31,9 @@
 // RUN: %swift-ide-test -test-input-complete -source-filename %S/Inputs/type_incomplete3.swift | %FileCheck %s -check-prefix=INCOMPLETE
 // RUN: %swift-ide-test -test-input-complete -source-filename %S/Inputs/type_incomplete4.swift | %FileCheck %s -check-prefix=INCOMPLETE
 // RUN: %swift-ide-test -test-input-complete -source-filename %S/Inputs/invalid_interpolation1.swift | %FileCheck %s -check-prefix=COMPLETE
+// RUN: %swift-ide-test -test-input-complete -source-filename %S/Inputs/multi_line_string1.swift | %FileCheck %s -check-prefix=INCOMPLETE
+// RUN: %swift-ide-test -test-input-complete -source-filename %S/Inputs/multi_line_string2.swift | %FileCheck %s -check-prefix=INCOMPLETE
+// RUN: %swift-ide-test -test-input-complete -source-filename %S/Inputs/multi_line_string3.swift | %FileCheck %s -check-prefix=INCOMPLETE
 
 // INCOMPLETE: IS_INCOMPLETE
 // COMPLETE: IS_COMPLETE