clang-format: [JS] revert over-eager ASI check.

[mprobst]

Summary

Change r291428 introduced ASI detection after closing curly braces. That would generally be correct, however this breaks indentation for structural statements. What happens is that CompoundStatementIndenter increases indentation for the current line, then after reading ASI creates a new line (with the increased line level), and only after the structural parser sees e.g. the if/then/else branch closed, line level is reduced. That leads to the new line started by ASI having a level too high.

lib/Format/UnwrappedLineParser.cpp

void UnwrappedLineParser::readTokenWithJavaScriptASI() {
   bool NextMustBeValue = mustBeJSIdentOrValue(Keywords, Next);
   bool NextEndsTemplateExpr =
       Next->is(TT_TemplateString) && Next->TokenText.startswith("}");
   if (NextMustBeValue && !NextEndsTemplateExpr && !PreviousStartsTemplateExpr &&
       (PreviousMustBeValue ||
        Previous->isOneOf(tok::r_square, tok::r_paren, tok::plusplus,
                          tok::minusminus)))
     return addUnwrappedLine();
-  if ((PreviousMustBeValue || Previous->is(tok::r_brace)) &&
-      isJSDeclOrStmt(Keywords, Next))
+  if (PreviousMustBeValue && isJSDeclOrStmt(Keywords, Next))
     return addUnwrappedLine();
 }
 
 void UnwrappedLineParser::parseStructuralElement() {
   assert(!FormatTok->is(tok::l_brace));
   if (Style.Language == FormatStyle::LK_TableGen &&
       FormatTok->is(tok::pp_include)) {
     nextToken();

unittests/Format/FormatTestJS.cpp

TEST_F(FormatTestJS, AutomaticSemicolonInsertionHeuristic) {
   verifyFormat("a = 's'\n"
                "return 1",
                "a = 's'\n"
                "  return   1");
   verifyFormat("a = null\n"
                "return 1",
                "a = null\n"
                "  return   1");
+  // Below "class Y {}" should ideally be on its own line.
   verifyFormat(
       "x = {\n"
       "  a: 1\n"
-      "}\n"
-      "class Y {}",
+      "} class Y {}",
       "  x  =  {a  : 1}\n"
       "   class  Y {  }");
+  verifyFormat(
+      "if (x) {\n"
+      "}\n"
+      "return 1",
+      "if (x) {}\n"
+      " return   1");
+  verifyFormat(
+      "if (x) {\n"
+      "}\n"
+      "class X {}",
+      "if (x) {}\n"
+      " class X {}");
 }
 
 TEST_F(FormatTestJS, ImportExportASI) {
   verifyFormat(
       "import {x} from 'y'\n"
       "export function z() {}",
       "import   {x} from 'y'\n"
       "  export function z() {}");
+  // Below "class Y {}" should ideally be on its own line.
   verifyFormat(
-      "export {x}\n"
-      "class Y {}",
+      "export {x} class Y {}",
       "  export {x}\n"
       "  class  Y {\n}");
+  verifyFormat(
+      "if (x) {\n"
+      "}\n"
+      "export class Y {}",
+      "if ( x ) { }\n"
+      " export class Y {}");
 }
 
 TEST_F(FormatTestJS, ClosureStyleCasts) {
   verifyFormat("var x = /** @type {foo} */ (bar);");
 }
 
 TEST_F(FormatTestJS, TryCatch) {
   verifyFormat("try {\n"