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NPE during code completion of var'ed variable #495

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fbricon opened this issue Oct 26, 2022 · 4 comments
Closed

NPE during code completion of var'ed variable #495

fbricon opened this issue Oct 26, 2022 · 4 comments
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bug Something isn't working

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@fbricon
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fbricon commented Oct 26, 2022 •
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In Eclipse 2022-09, org.eclipse.jdt.feature.group 3.18.1300.v20220831-1800, on a Java 18 project, code completion fails with an error popup at o.| in the following snippet:

package foo;

import java.util.*;

public class Bar {

	public void foo(List<String> characters) {
		for (String character : characters) {
			characters.forEach(c -> {
				var o = Optional.of(c);
				o.| // completion fails hard here
			});
			System.err.println(character);
		}
	}
}

Screenshot 2022-10-26 at 15 13 22

java.lang.NullPointerException: Cannot invoke "org.eclipse.jdt.internal.compiler.lookup.TypeBinding.needsUncheckedConversion(org.eclipse.jdt.internal.compiler.lookup.TypeBinding)" because "argumentType" is null
	at org.eclipse.jdt.internal.compiler.ast.ASTNode.checkInvocationArgument(ASTNode.java:363)
	at org.eclipse.jdt.internal.compiler.ast.ASTNode.checkInvocationArguments(ASTNode.java:449)
	at org.eclipse.jdt.internal.compiler.ast.MessageSend.resolveType(MessageSend.java:956)
	at org.eclipse.jdt.internal.compiler.ast.LocalDeclaration.resolve(LocalDeclaration.java:346)
	at org.eclipse.jdt.internal.compiler.ast.LocalDeclaration.resolve(LocalDeclaration.java:259)
	at org.eclipse.jdt.internal.compiler.ast.Block.resolve(Block.java:131)
	at org.eclipse.jdt.internal.compiler.ast.LambdaExpression.resolveType(LambdaExpression.java:472)
	at org.eclipse.jdt.internal.compiler.ast.ASTNode.resolvePolyExpressionArguments(ASTNode.java:743)
	at org.eclipse.jdt.internal.compiler.ast.MessageSend.findMethodBinding(MessageSend.java:1027)
	at org.eclipse.jdt.internal.compiler.ast.MessageSend.resolveType(MessageSend.java:835)
	at org.eclipse.jdt.internal.compiler.ast.Expression.resolve(Expression.java:1113)
	at org.eclipse.jdt.internal.compiler.ast.Block.resolve(Block.java:131)
	at org.eclipse.jdt.internal.compiler.ast.Block.resolve(Block.java:131)
	at org.eclipse.jdt.internal.compiler.ast.Block.resolve(Block.java:131)
	at org.eclipse.jdt.internal.compiler.ast.ForeachStatement.resolve(ForeachStatement.java:682)
	at org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration.resolveStatements(AbstractMethodDeclaration.java:662)
	at org.eclipse.jdt.internal.compiler.ast.MethodDeclaration.resolveStatements(MethodDeclaration.java:388)
	at org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration.resolve(AbstractMethodDeclaration.java:571)
	at org.eclipse.jdt.internal.compiler.ast.TypeDeclaration.resolve(TypeDeclaration.java:1503)
	at org.eclipse.jdt.internal.compiler.ast.TypeDeclaration.resolve(TypeDeclaration.java:1628)
	at org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration.resolve(CompilationUnitDeclaration.java:667)
	at org.eclipse.jdt.internal.codeassist.CompletionEngine.complete(CompletionEngine.java:2328)
	at org.eclipse.jdt.internal.core.Openable.codeComplete(Openable.java:136)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeComplete(CompilationUnit.java:367)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeComplete(CompilationUnit.java:357)
	at org.eclipse.jdt.internal.ui.text.java.JavaCompletionProposalComputer.internalComputeCompletionProposals(JavaCompletionProposalComputer.java:256)
	at org.eclipse.jdt.internal.ui.text.java.JavaCompletionProposalComputer.computeCompletionProposals(JavaCompletionProposalComputer.java:218)
	at org.eclipse.jdt.internal.ui.text.java.JavaTypeCompletionProposalComputer.computeCompletionProposals(JavaTypeCompletionProposalComputer.java:65)
	at org.eclipse.jdt.internal.ui.text.java.CompletionProposalComputerDescriptor.computeCompletionProposals(CompletionProposalComputerDescriptor.java:348)
	at org.eclipse.jdt.internal.ui.text.java.CompletionProposalCategory.computeCompletionProposals(CompletionProposalCategory.java:340)
	at org.eclipse.jdt.internal.ui.text.java.ContentAssistProcessor.collectProposals(ContentAssistProcessor.java:333)
	at org.eclipse.jdt.internal.ui.text.java.ContentAssistProcessor.computeCompletionProposals(ContentAssistProcessor.java:289)
	at org.eclipse.jface.text.contentassist.AsyncCompletionProposalPopup.lambda$10(AsyncCompletionProposalPopup.java:378)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
	at org.eclipse.jface.text.contentassist.AsyncCompletionProposalPopup.lambda$9(AsyncCompletionProposalPopup.java:377)
	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1768)
	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.exec(CompletableFuture.java:1760)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:373)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182)
	at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165)

If you replace var o = Optional.of(c); with Optional<String> o = Optional.of(c);, completion works without errors.

For context, I was trying to look into code completion failure reported in vscode-java (powered by JDT.LS), that might or might not be related.
@fbricon
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fbricon commented Oct 26, 2022 •
edited
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Error is reproducible with the latest JDT I-Build (3.18.1400.v20221025-1800).
Updated stacktrace (line numbers changed):

java.lang.NullPointerException: Cannot invoke "org.eclipse.jdt.internal.compiler.lookup.TypeBinding.needsUncheckedConversion(org.eclipse.jdt.internal.compiler.lookup.TypeBinding)" because "argumentType" is null
	at org.eclipse.jdt.internal.compiler.ast.ASTNode.checkInvocationArgument(ASTNode.java:364)
	at org.eclipse.jdt.internal.compiler.ast.ASTNode.checkInvocationArguments(ASTNode.java:450)
	at org.eclipse.jdt.internal.compiler.ast.MessageSend.resolveType(MessageSend.java:956)
	at org.eclipse.jdt.internal.compiler.ast.LocalDeclaration.resolve(LocalDeclaration.java:346)
	at org.eclipse.jdt.internal.compiler.ast.LocalDeclaration.resolve(LocalDeclaration.java:259)
	at org.eclipse.jdt.internal.compiler.ast.Block.resolve(Block.java:131)
	at org.eclipse.jdt.internal.compiler.ast.LambdaExpression.resolveType(LambdaExpression.java:472)
	at org.eclipse.jdt.internal.compiler.ast.ASTNode.resolvePolyExpressionArguments(ASTNode.java:744)
	at org.eclipse.jdt.internal.compiler.ast.MessageSend.findMethodBinding(MessageSend.java:1027)
	at org.eclipse.jdt.internal.compiler.ast.MessageSend.resolveType(MessageSend.java:835)
	at org.eclipse.jdt.internal.compiler.ast.Expression.resolve(Expression.java:1113)
	at org.eclipse.jdt.internal.compiler.ast.Block.resolve(Block.java:131)
	at org.eclipse.jdt.internal.compiler.ast.Block.resolve(Block.java:131)
	at org.eclipse.jdt.internal.compiler.ast.ForeachStatement.resolve(ForeachStatement.java:682)
	at org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration.resolveStatements(AbstractMethodDeclaration.java:662)
	at org.eclipse.jdt.internal.compiler.ast.MethodDeclaration.resolveStatements(MethodDeclaration.java:388)
	at org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration.resolve(AbstractMethodDeclaration.java:571)
	at org.eclipse.jdt.internal.compiler.ast.TypeDeclaration.resolve(TypeDeclaration.java:1503)
	at org.eclipse.jdt.internal.compiler.ast.TypeDeclaration.resolve(TypeDeclaration.java:1628)
	at org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration.resolve(CompilationUnitDeclaration.java:667)
	at org.eclipse.jdt.internal.codeassist.CompletionEngine.complete(CompletionEngine.java:2328)
	at org.eclipse.jdt.internal.core.Openable.codeComplete(Openable.java:136)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeComplete(CompilationUnit.java:367)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeComplete(CompilationUnit.java:357)
	at org.eclipse.jdt.internal.ui.text.java.JavaCompletionProposalComputer.internalComputeCompletionProposals(JavaCompletionProposalComputer.java:256)
	at org.eclipse.jdt.internal.ui.text.java.JavaCompletionProposalComputer.computeCompletionProposals(JavaCompletionProposalComputer.java:218)
	at org.eclipse.jdt.internal.ui.text.java.JavaTypeCompletionProposalComputer.computeCompletionProposals(JavaTypeCompletionProposalComputer.java:65)
	at org.eclipse.jdt.internal.ui.text.java.CompletionProposalComputerDescriptor.computeCompletionProposals(CompletionProposalComputerDescriptor.java:348)
	at org.eclipse.jdt.internal.ui.text.java.CompletionProposalCategory.computeCompletionProposals(CompletionProposalCategory.java:340)
	at org.eclipse.jdt.internal.ui.text.java.ContentAssistProcessor.collectProposals(ContentAssistProcessor.java:333)
	at org.eclipse.jdt.internal.ui.text.java.ContentAssistProcessor.computeCompletionProposals(ContentAssistProcessor.java:289)
	at org.eclipse.jface.text.contentassist.AsyncCompletionProposalPopup.lambda$10(AsyncCompletionProposalPopup.java:378)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
	at org.eclipse.jface.text.contentassist.AsyncCompletionProposalPopup.lambda$9(AsyncCompletionProposalPopup.java:377)
	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1768)
	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.exec(CompletableFuture.java:1760)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:373)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182)
	at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165)

The weird thing is I don't see the error with the same code in JDT.LS

@rgrunber
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It's reproducible in JDT-LS. I needed to disable lombok support to get the stack trace :

stacktrace 
[Error - 10:28:14 a.m.] Oct. 26, 2022, 10:28:14 a.m. Problem with codeComplete for file:///tmp/foo/foo/Bar.java
Cannot invoke "org.eclipse.jdt.internal.compiler.lookup.TypeBinding.needsUncheckedConversion(org.eclipse.jdt.internal.compiler.lookup.TypeBinding)" because "argumentType" is null
java.lang.NullPointerException: Cannot invoke "org.eclipse.jdt.internal.compiler.lookup.TypeBinding.needsUncheckedConversion(org.eclipse.jdt.internal.compiler.lookup.TypeBinding)" because "argumentType" is null
	at org.eclipse.jdt.internal.compiler.ast.ASTNode.checkInvocationArgument(ASTNode.java:364)
	at org.eclipse.jdt.internal.compiler.ast.ASTNode.checkInvocationArguments(ASTNode.java:450)
	at org.eclipse.jdt.internal.compiler.ast.MessageSend.resolveType(MessageSend.java:956)
	at org.eclipse.jdt.internal.compiler.ast.LocalDeclaration.resolve(LocalDeclaration.java:346)
	at org.eclipse.jdt.internal.compiler.ast.LocalDeclaration.resolve(LocalDeclaration.java:259)
	at org.eclipse.jdt.internal.compiler.ast.Block.resolve(Block.java:131)
	at org.eclipse.jdt.internal.compiler.ast.LambdaExpression.resolveType(LambdaExpression.java:472)
	at org.eclipse.jdt.internal.compiler.ast.ASTNode.resolvePolyExpressionArguments(ASTNode.java:744)
	at org.eclipse.jdt.internal.compiler.ast.MessageSend.findMethodBinding(MessageSend.java:1027)
	at org.eclipse.jdt.internal.compiler.ast.MessageSend.resolveType(MessageSend.java:835)
	at org.eclipse.jdt.internal.compiler.ast.Expression.resolve(Expression.java:1113)
	at org.eclipse.jdt.internal.compiler.ast.Block.resolve(Block.java:131)
	at org.eclipse.jdt.internal.compiler.ast.Block.resolve(Block.java:131)
	at org.eclipse.jdt.internal.compiler.ast.ForeachStatement.resolve(ForeachStatement.java:682)
	at org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration.resolveStatements(AbstractMethodDeclaration.java:662)
	at org.eclipse.jdt.internal.compiler.ast.MethodDeclaration.resolveStatements(MethodDeclaration.java:388)
	at org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration.resolve(AbstractMethodDeclaration.java:571)
	at org.eclipse.jdt.internal.compiler.ast.TypeDeclaration.resolve(TypeDeclaration.java:1503)
	at org.eclipse.jdt.internal.compiler.ast.TypeDeclaration.resolve(TypeDeclaration.java:1628)
	at org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration.resolve(CompilationUnitDeclaration.java:667)
	at org.eclipse.jdt.internal.codeassist.CompletionEngine.complete(CompletionEngine.java:2328)
	at org.eclipse.jdt.internal.core.Openable.codeComplete(Openable.java:136)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeComplete(CompilationUnit.java:367)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeComplete(CompilationUnit.java:357)
	at org.eclipse.jdt.ls.core.internal.handlers.CompletionHandler.computeContentAssist(CompletionHandler.java:164)
	at org.eclipse.jdt.ls.core.internal.handlers.CompletionHandler.completion(CompletionHandler.java:86)
	at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$5(JDTLanguageServer.java:570)
	at org.eclipse.jdt.ls.core.internal.BaseJDTLanguageServer.lambda$0(BaseJDTLanguageServer.java:75)
	at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(Unknown Source)
	at java.base/java.util.concurrent.CompletableFuture$Completion.exec(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinPool.scan(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source)

@fbricon
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fbricon commented Oct 26, 2022

Forgot to mention the most fun part, i.e. removing the System.err.println(character); line below the completion site also fixes the issue.

@fbricon fbricon mentioned this issue Oct 26, 2022
Closed
@trancexpress trancexpress added the bug Something isn't working label Apr 3, 2023
@jukzi
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jukzi commented May 24, 2023

Can reproduce. current stacktrace:

java.version=17.0.7
java.lang.NullPointerException: Cannot invoke "org.eclipse.jdt.internal.compiler.lookup.TypeBinding.needsUncheckedConversion(org.eclipse.jdt.internal.compiler.lookup.TypeBinding)" because "argumentType" is null
	at org.eclipse.jdt.internal.compiler.ast.ASTNode.checkInvocationArgument(ASTNode.java:377)
	at org.eclipse.jdt.internal.compiler.ast.ASTNode.checkInvocationArguments(ASTNode.java:463)
	at org.eclipse.jdt.internal.compiler.ast.MessageSend.resolveType(MessageSend.java:956)
	at org.eclipse.jdt.internal.compiler.ast.LocalDeclaration.resolve(LocalDeclaration.java:346)
	at org.eclipse.jdt.internal.compiler.ast.LocalDeclaration.resolve(LocalDeclaration.java:259)
	at org.eclipse.jdt.internal.compiler.ast.Block.resolve(Block.java:131)
	at org.eclipse.jdt.internal.compiler.ast.LambdaExpression.resolveType(LambdaExpression.java:470)
	at org.eclipse.jdt.internal.compiler.ast.ASTNode.resolvePolyExpressionArguments(ASTNode.java:757)
	at org.eclipse.jdt.internal.compiler.ast.MessageSend.findMethodBinding(MessageSend.java:1027)
	at org.eclipse.jdt.internal.compiler.ast.MessageSend.resolveType(MessageSend.java:835)
	at org.eclipse.jdt.internal.compiler.ast.Expression.resolve(Expression.java:1113)
	at org.eclipse.jdt.internal.compiler.ast.Block.resolve(Block.java:131)
	at org.eclipse.jdt.internal.compiler.ast.Block.resolve(Block.java:131)
	at org.eclipse.jdt.internal.compiler.ast.Statement.resolveWithPatternVariablesInScope(Statement.java:547)
	at org.eclipse.jdt.internal.compiler.ast.ForeachStatement.resolve(ForeachStatement.java:735)
	at org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration.resolveStatements(AbstractMethodDeclaration.java:662)
	at org.eclipse.jdt.internal.compiler.ast.MethodDeclaration.resolveStatements(MethodDeclaration.java:388)
	at org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration.resolve(AbstractMethodDeclaration.java:571)
	at org.eclipse.jdt.internal.compiler.ast.TypeDeclaration.resolve(TypeDeclaration.java:1506)
	at org.eclipse.jdt.internal.compiler.ast.TypeDeclaration.resolve(TypeDeclaration.java:1631)
	at org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration.resolve(CompilationUnitDeclaration.java:668)
	at org.eclipse.jdt.internal.codeassist.CompletionEngine.complete(CompletionEngine.java:2340)
	at org.eclipse.jdt.internal.core.Openable.codeComplete(Openable.java:136)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeComplete(CompilationUnit.java:367)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeComplete(CompilationUnit.java:357)
	at org.eclipse.jdt.internal.ui.text.java.JavaCompletionProposalComputer.internalComputeCompletionProposals(JavaCompletionProposalComputer.java:256)
	at org.eclipse.jdt.internal.ui.text.java.JavaCompletionProposalComputer.computeCompletionProposals(JavaCompletionProposalComputer.java:218)
	at org.eclipse.jdt.internal.ui.text.java.JavaTypeCompletionProposalComputer.computeCompletionProposals(JavaTypeCompletionProposalComputer.java:65)
	at org.eclipse.jdt.internal.ui.text.java.CompletionProposalComputerDescriptor.computeCompletionProposals(CompletionProposalComputerDescriptor.java:348)
	at org.eclipse.jdt.internal.ui.text.java.CompletionProposalCategory.computeCompletionProposals(CompletionProposalCategory.java:340)
	at org.eclipse.jdt.internal.ui.text.java.ContentAssistProcessor.collectProposals(ContentAssistProcessor.java:333)
	at org.eclipse.jdt.internal.ui.text.java.ContentAssistProcessor.computeCompletionProposals(ContentAssistProcessor.java:289)
	at org.eclipse.jface.text.contentassist.AsyncCompletionProposalPopup.lambda$10(AsyncCompletionProposalPopup.java:378)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
	at org.eclipse.jface.text.contentassist.AsyncCompletionProposalPopup.lambda$9(AsyncCompletionProposalPopup.java:377)
	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1768)
	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.exec(CompletableFuture.java:1760)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:373)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182)
	at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165)

according to MessageSend.resolveType(BlockScope) line: 791 argumentType==null means argumentsHaveErrors
for argumentsHaveErrors resolveType is supposed to return null (see line 822) however that eager return is only taken when MessageSend.arguments is not yet filled.

i'll propose a fix which show completion
image

jukzi pushed a commit to jukzi/eclipse.jdt.core that referenced this issue May 24, 2023
@EcljpseB0T
MessageSend: handle argumentsHaveErrors - fixes eclipse-jdt#495
e4159e6
@jukzi jukzi mentioned this issue May 24, 2023
Merged
jukzi pushed a commit to jukzi/eclipse.jdt.core that referenced this issue Jun 19, 2023
@EcljpseB0T @jukzi
MessageSend: handle argumentsHaveErrors - fixes eclipse-jdt#495
ae3464e
jukzi pushed a commit to jukzi/eclipse.jdt.core that referenced this issue Jun 19, 2023
@EcljpseB0T @jukzi
MessageSend: handle argumentsHaveErrors - fixes eclipse-jdt#495
2b604ee
jukzi pushed a commit to jukzi/eclipse.jdt.core that referenced this issue Jun 20, 2023
@EcljpseB0T @jukzi
MessageSend: handle argumentsHaveErrors - fixes eclipse-jdt#495
037eebe
@jukzi jukzi closed this as completed in 80de332 Jul 21, 2023
robstryker pushed a commit to robstryker/eclipse.jdt.core that referenced this issue Jul 18, 2024
@EcljpseB0T @jukzi
MessageSend: handle argumentsHaveErrors - fixes eclipse-jdt#495
fe41c8e
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@fbricon @rgrunber @trancexpress @jukzi