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Eric Milles edited comment on GROOVY-10807 at 11/4/22 4:18 PM: --------------------------------------------------------------- I'm still investigating "Comparator.comparing(NoticeRenderer::getComponentDisplayName)". The type parameters of {{comparing(Function)}} are the source of the issue. I do have a fix so you can write: {code:groovy} Comparator<String> COMPARATOR = Comparator.<String,String>comparing(NoticeRenderer::getComponentDisplayName) {code} For now you can also write: {code:groovy} Comparator<String> COMPARATOR = Comparator.comparing((Function<String,String>) NoticeRenderer::getComponentDisplayName) {code} was (Author: emilles): I'm still investigating "Comparator.comparing(NoticeRenderer::getComponentDisplayName)". The type parameters of {{comparing(Function)}} are the source of the issue. I do have a fix so you can write: {code:groovy} Comparator<String> COMPARATOR = Comparator.<String,String>comparing(NoticeRenderer::getComponentDisplayName) {code} For now you can write: {code:groovy} Comparator<String> COMPARATOR = Comparator.comparing((Function<String,String>) NoticeRenderer::getComponentDisplayName) {code} > STC seems to lose type information through method references > ------------------------------------------------------------ > > Key: GROOVY-10807 > URL: https://issues.apache.org/jira/browse/GROOVY-10807 > Project: Groovy > Issue Type: Bug > Components: Static compilation > Affects Versions: 3.0.12, 3.0.13, 4.0.6 > Reporter: Sterling Greene > Assignee: Eric Milles > Priority: Major > > This compiles in Groovy 3.0.11, but it does not compile in Groovy 3.0.12 or > 3.0.13. > {code:java} > import groovy.transform.CompileStatic > @CompileStatic > abstract class NoticeRenderer { > private static final Comparator<String> COMPARATOR = > Comparator<String>.comparing(NoticeRenderer::getComponentDisplayName) > > public static String getComponentDisplayName(String component) { > return component; > } > } > {code} > The error is > bq. Failed to find the expected > method[getComponentDisplayName(java.lang.Object)] in the type[NoticeRenderer] > at line: 5, column: 79 > I think something is going sideways when inferring the types to comparing. > Removing the type bound on the Comparator doesn't change the error. > bq. private static final Comparator<String> COMPARATOR = > Comparator.comparing(NoticeRenderer::getComponentDisplayName) > The type bound could be on the method itself. This produces the same error. > bq. private static final Comparator<String> COMPARATOR = > Comparator.<String>comparing(NoticeRenderer::getComponentDisplayName) > But comparing actually has two type parameters, so it's a little weird that > the above doesn't complain. Specifying both type parameters still produces > the same error. > bq. private static final Comparator<String> COMPARATOR = Comparator.<String, > String>comparing(NoticeRenderer::getComponentDisplayName) > If I mistakenly put the type bounds on Comparator, I don't expect this to > work, but it produces BUG! output: > private static final Comparator<String> COMPARATOR = Comparator<String, > String>.comparing(NoticeRenderer::getComponentDisplayName) > bq. BUG! exception in phase 'instruction selection' in source unit > 'ConsoleScript34' Expected earlier checking to detect generics parameter > arity mismatch > bq. Expected: java.util.Comparator<T> > bq. Supplied: java.util.Comparator<java.lang.String,java.lang.String> > In Java, you don't need the type information at all: > bq. private static final Comparator<String> COMPARATOR = > Comparator.comparing(NoticeRenderer::getComponentDisplayName); > If you wanted to be verbose in Java, you could specify the bounds: > bq. private static final Comparator<String> COMPARATOR = Comparator.<String, > String>comparing(NoticeRenderer::getComponentDisplayName); > As a workaround... > If I avoid the use of the method reference, I can make something pass the > static compiler: > bq. private static final Comparator<String> COMPARATOR = > Comparator.<String>comparing( { String it -> getComponentDisplayName(it) }) > I need both the type bound on comparing and the type of the parameter. -- This message was sent by Atlassian Jira (v8.20.10#820010)