Bug 547891 - [13] flag error for unqualified yield method invocationsY20190715-2335

and yield type - yield yield processing

Change-Id: Ie5df9fb9d6e71a120cf9beffbf0121f762f25830

2 files changed, 67 insertions, 4 deletions

diff --git a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SwitchExpressionsYieldTest.java b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SwitchExpressionsYieldTest.java
index 90818e436d..17bff8ecd2 100644
--- a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SwitchExpressionsYieldTest.java
+++ b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SwitchExpressionsYieldTest.java
@@ -3047,4 +3047,57 @@ public class SwitchExpressionsYieldTest extends AbstractRegressionTest {
 				new String[] {""},
 				options);
 	}
+	public void testBug547891_15() {
+		if (this.complianceLevel < ClassFileConstants.JDK12)
+			return;
+		Map<String, String> options = getCompilerOptions();
+		options.put(CompilerOptions.OPTION_EnablePreviews, CompilerOptions.ENABLED);
+		options.put(CompilerOptions.OPTION_ReportPreviewFeatures, CompilerOptions.WARNING);
+		String message = 
+				"----------\n" + 
+				"1. ERROR in X.java (at line 6)\n" + 
+				"	case 1 -> yield();\n" + 
+				"	          ^^^^^^^\n" + 
+				"restricted identifier yield not allowed here - method calls need to be qualified\n" + 
+				"----------\n" + 
+				"2. ERROR in X.java (at line 8)\n" + 
+				"	case 3 -> {yield yield();}\n" + 
+				"	                 ^^^^^^^\n" + 
+				"restricted identifier yield not allowed here - method calls need to be qualified\n" + 
+				"----------\n" + 
+				"3. ERROR in X.java (at line 10)\n" + 
+				"	default -> { yield yield();}\n" + 
+				"	                   ^^^^^^^\n" + 
+				"restricted identifier yield not allowed here - method calls need to be qualified\n" + 
+				"----------\n";
+		
+		this.runNegativeTest(new String[] {
+				"X.java",
+				"public class X {\n"+
+				"\n"+
+				"	@SuppressWarnings(\"preview\")\n"+
+				"	public static int foo(int i) {\n"+
+				"		int r = switch(i) {\n"+
+				"			case 1 -> yield();\n"+
+				"			case 2 -> X.yield();\n"+
+				"			case 3 -> {yield yield();}\n"+
+				"			case 4 -> {yield X.yield();}\n"+
+				"			default -> { yield yield();}\n"+
+				"		};\n"+
+				"		return r;\n"+
+				"	}\n"+
+				"	public static int yield() {\n"+
+				"		return 0;\n"+
+				"	}\n"+
+				"	public static void main(String[] args) {\n"+
+				"		System.out.println(X.foo(0));\n"+
+				"	}\n"+
+				"}\n"
+			},
+			message,
+			null,
+			true,
+			new String[] { "--enable-preview"},
+			options);
+	}
 }
\ No newline at end of file
diff --git a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/parser/Scanner.java b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/parser/Scanner.java
index 19c177b018..3645096bc0 100644
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/parser/Scanner.java
+++ b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/parser/Scanner.java
@@ -125,6 +125,10 @@ public class Scanner implements TerminalTokens {
 	protected ScanContext scanContext = null;
 	protected boolean insideModuleInfo = false;
 
+	enum ScanYieldContext {
+		EXPECTING_YIELD, FLAGGED_YIELD, INACTIVE
+	}
+	protected ScanYieldContext scanYieldContext = null;
 	public static final String END_OF_SOURCE = "End_Of_Source"; //$NON-NLS-1$
 
 	public static final String INVALID_HEXA = "Invalid_Hexa_Literal"; //$NON-NLS-1$
@@ -2743,8 +2747,7 @@ public boolean isInModuleDeclaration() {
 			(this.activeParser != null ? this.activeParser.isParsingModuleDeclaration() : false);
 }
 protected boolean areRestrictedModuleKeywordsActive() {
-	return this.scanContext != null && this.scanContext != ScanContext.INACTIVE &&
-			this.scanContext != ScanContext.EXPECTING_YIELD;
+	return this.scanContext != null && this.scanContext != ScanContext.INACTIVE;
 }
 void updateScanContext(int token) {
 	switch (token) {
@@ -5007,20 +5010,27 @@ private boolean mayBeAtAnYieldStatement() {
 	}
 }
 int disambiguatedRestrictedIdentifier(int restrictedKeywordToken) {
+	if (restrictedKeywordToken != TokenNameRestrictedIdentifierYield)
+		return restrictedKeywordToken; // safety net - only yield processed here!
 	if (!this.previewEnabled)
 		return TokenNameIdentifier;
-	if (this.scanContext == ScanContext.EXPECTING_YIELD)
+	if (this.scanYieldContext == ScanYieldContext.FLAGGED_YIELD) // nested yield implies identifier.
+		return TokenNameIdentifier;		
+	if (this.scanYieldContext == ScanYieldContext.EXPECTING_YIELD) {
+		this.scanYieldContext = ScanYieldContext.FLAGGED_YIELD;
 		return TokenNameRestrictedIdentifierYield;
+	}
 
 	if (this.sourceLevel < ClassFileConstants.JDK13)
 		return TokenNameIdentifier;
 
 	int token = TokenNameIdentifier;
+	
 	// not working - check intermittent parser rule definition possibility.
 	final VanguardParser parser = getVanguardParser();
 	if (restrictedKeywordToken == TokenNameRestrictedIdentifierYield  && mayBeAtAnYieldStatement()) {
 		parser.scanner.resetTo(this.startPosition, this.eofPosition - 1);
-		parser.scanner.scanContext = ScanContext.EXPECTING_YIELD;
+		parser.scanner.scanYieldContext = ScanYieldContext.EXPECTING_YIELD;
 		if (parser.parse(Goal.YieldStatementGoal) == VanguardParser.SUCCESS) {
 			token = TokenNameRestrictedIdentifierYield;
 		}