Correct 'throw' to 'throws' in function signatures and types.

rdar://21328447

Swift SVN r30514

Author: rjmccall

include/swift/AST/DiagnosticsParse.def

@@ -585,6 +585,8 @@ ERROR(throws_after_function_result,type_parsing,none,
       "'throws' may only occur before '->'", ())
 ERROR(rethrows_after_function_result,type_parsing,none,
       "'rethrows' may only occur before '->'", ())
+ERROR(throw_in_function_type,type_parsing,none,
+      "expected throwing specifier; did you mean 'throws'?", ())
 
 // Enum Types
 ERROR(expected_expr_enum_case_raw_value,type_parsing,PointsToFirstBadToken,

lib/Parse/ParsePattern.cpp

@@ -640,6 +640,10 @@ Parser::parseFunctionSignature(Identifier SimpleName,
   } else if (Tok.is(tok::kw_rethrows)) {
     throwsLoc = consumeToken();
     rethrows = true;
+  } else if (Tok.is(tok::kw_throw)) {
+    throwsLoc = consumeToken();
+    diagnose(throwsLoc, diag::throw_in_function_type)
+      .fixItReplace(throwsLoc, "throws");
   }
 
   SourceLoc arrowLoc;

lib/Parse/ParseType.cpp

@@ -162,11 +162,20 @@ ParserResult<TypeRepr> Parser::parseType(Diag<> MessageID) {
 
   if (ty.isNull())
     return nullptr;
-  
+
+  // Parse a throws specifier.  'throw' is probably a typo for 'throws',
+  // but in local contexts we could just be at the end of a statement,
+  // so we need to check for the arrow.
   ParserPosition beforeThrowsPos;
   SourceLoc throwsLoc;
   bool rethrows = false;
-  if (Tok.isAny(tok::kw_throws, tok::kw_rethrows)) {
+  if (Tok.isAny(tok::kw_throws, tok::kw_rethrows) ||
+      (Tok.is(tok::kw_throw) && peekToken().is(tok::arrow))) {
+    if (Tok.is(tok::kw_throw)) {
+      diagnose(Tok.getLoc(), diag::throw_in_function_type)
+        .fixItReplace(Tok.getLoc(), "throws");
+    }
+
     beforeThrowsPos = getParserPosition();
     rethrows = Tok.is(tok::kw_rethrows);
     throwsLoc = consumeToken();

test/Parse/errors.swift

@@ -97,3 +97,12 @@ func postThrows() -> Int throws { // expected-error{{'throws' may only occur bef
 func postRethrows(f: () throws -> Int) -> Int rethrows { // expected-error{{'rethrows' may only occur before '->'}}{{40-40=rethrows }}{{46-55=}}
   return try f()
 }
+
+// rdar://21328447
+func fixitThrow0() throw {} // expected-error{{expected throwing specifier; did you mean 'throws'?}} {{20-25=throws}}
+func fixitThrow1() throw -> Int {} // expected-error{{expected throwing specifier; did you mean 'throws'?}} {{20-25=throws}}
+func fixitThrow2() throws {
+  var _: (Int)
+  throw MSV.Foo
+  var _: Int throw -> Int // expected-error{{expected throwing specifier; did you mean 'throws'?}} {{14-19=throws}}
+}