Code Inspection not working

Hi,

Please try File | Invalidate Caches / Restart..., if doesn't help try to delete the system sub-directory (https://intellij-support.jetbrains.com/hc/articles/206544519) and then start PyCharm again.

If nothing helps, please upload your idea.log (Help | Show Log in...) to https://uploads.services.jetbrains.com/ zipped and let me know the name of that zip file.

Invalidating the cache or removing the named directory didn't help.

The log file repeatedly contains the following message:

2018-11-01 15:15:03,912 [ 553561]  ERROR - ex.GlobalInspectionContextImpl - PyCharm 2018.2.4  Build #PY-182.4505.26 
2018-11-01 15:15:03,912 [ 553561]  ERROR - ex.GlobalInspectionContextImpl - JDK: 1.8.0_152-release 
2018-11-01 15:15:03,912 [ 553561]  ERROR - ex.GlobalInspectionContextImpl - VM: OpenJDK 64-Bit Server VM 
2018-11-01 15:15:03,912 [ 553561]  ERROR - ex.GlobalInspectionContextImpl - Vendor: JetBrains s.r.o 
2018-11-01 15:15:03,912 [ 553561]  ERROR - ex.GlobalInspectionContextImpl - OS: Linux 
2018-11-01 15:15:03,912 [ 553561]  ERROR - ex.GlobalInspectionContextImpl - Last Action: InspectCode 
2018-11-01 15:15:03,936 [ 553585]   INFO - ex.GlobalInspectionContextImpl - Code inspection finished. Took 782ms 
2018-11-01 15:15:04,500 [ 554149]  ERROR - aemon.impl.PassExecutorService - one.util.streamex.StreamEx.nonNull()Lone/util/streamex/StreamEx; 
java.lang.NoSuchMethodError: one.util.streamex.StreamEx.nonNull()Lone/util/streamex/StreamEx;
    at com.jetbrains.python.psi.PyUtil.filterTopPriorityResults(PyUtil.java:591)
    at com.jetbrains.python.psi.resolve.PyResolveImportUtil.resolveModuleAt(PyResolveImportUtil.kt:160)
    at com.jetbrains.python.psi.resolve.PyResolveImportUtil.a(PyResolveImportUtil.kt:361)
    at com.jetbrains.python.psi.resolve.PyResolveImportUtil.access$resolveInRoot(PyResolveImportUtil.kt:1)
    at com.jetbrains.python.psi.resolve.PyResolveImportUtil$resultsFromRoots$visitor$1.visitRoot(PyResolveImportUtil.kt:312)
    at com.jetbrains.python.psi.resolve.RootVisitorHost.visitSdkRoots(RootVisitorHost.java:99)
    at com.jetbrains.python.psi.resolve.PyResolveImportUtil.c(PyResolveImportUtil.kt:342)
    at com.jetbrains.python.psi.resolve.PyResolveImportUtil.a(PyResolveImportUtil.kt:105)
    at com.jetbrains.python.psi.resolve.PyResolveImportUtil.resolveQualifiedName(PyResolveImportUtil.kt:75)
    at com.jetbrains.python.psi.impl.PyBuiltinCache.a(PyBuiltinCache.java:153)
    at com.jetbrains.python.psi.impl.PyBuiltinCache.getBuiltinsForSdk(PyBuiltinCache.java:137)
    at com.jetbrains.python.psi.resolve.PythonSdkPathCache.getBuiltins(PythonSdkPathCache.java:113)
    at com.jetbrains.python.psi.impl.PyBuiltinCache.getInstance(PyBuiltinCache.java:85)
    at com.jetbrains.python.psi.resolve.QualifiedNameFinder.a(QualifiedNameFinder.java:189)
    at com.jetbrains.python.psi.resolve.QualifiedNameFinder.b(QualifiedNameFinder.java:181)
    at com.intellij.psi.util.CachedValuesManager.lambda$getCachedValue$0(CachedValuesManager.java:140)
    at com.intellij.psi.impl.PsiCachedValueImpl.doCompute(PsiCachedValueImpl.java:49)
    at com.intellij.util.CachedValueBase.getValueWithLock(CachedValueBase.java:222)
    at com.intellij.psi.impl.PsiCachedValue.getValueWithLock(PsiCachedValue.java:60)
    at com.intellij.psi.impl.PsiCachedValueImpl.getValue(PsiCachedValueImpl.java:38)
    at com.intellij.psi.util.CachedValuesManager.getCachedValue(CachedValuesManager.java:136)
    at com.intellij.psi.util.CachedValuesManager.getCachedValue(CachedValuesManager.java:126)
    at com.jetbrains.python.psi.resolve.QualifiedNameFinder.getQualifiedName(QualifiedNameFinder.java:180)
    at com.jetbrains.python.psi.impl.PyClassImpl.getQualifiedName(PyClassImpl.java:257)
    at com.jetbrains.python.psi.impl.PyClassImpl.getSuperClassTypes(PyClassImpl.java:1332)
    at com.jetbrains.python.psi.types.PyClassTypeImpl.getSuperClassTypes(PyClassTypeImpl.java:125)
    at com.jetbrains.python.psi.impl.PyClassImpl.a(PyClassImpl.java:425)
    at com.jetbrains.python.psi.impl.PyClassImpl.b(PyClassImpl.java:1636)
    at com.jetbrains.python.psi.impl.PyClassImpl.e(PyClassImpl.java:1434)
    at com.jetbrains.python.psi.PyUtil.getNullableParameterizedCachedValue(PyUtil.java:819)
    at com.jetbrains.python.psi.PyUtil.getParameterizedCachedValue(PyUtil.java:797)
    at com.jetbrains.python.psi.impl.PyClassImpl.f(PyClassImpl.java:1430)
    at com.jetbrains.python.psi.impl.PyClassImpl.getAncestorTypes(PyClassImpl.java:1425)
    at com.jetbrains.extensions.python.PyClassExtKt.inherits(PyClassExt.kt:28)
    at com.jetbrains.python.testing.PythonUnitTestUtil.isTestClass(PythonUnitTestUtil.java:97)
    at com.jetbrains.python.testing.PyTestsSharedKt.isTestElement(PyTestsShared.kt:120)
    at com.jetbrains.python.testing.PyTestLineMarkerContributor.getInfo(PyTestLineMarkerContributor.kt:27)
    at com.intellij.execution.lineMarker.RunLineMarkerProvider.getLineMarkerInfo(RunLineMarkerProvider.java:46)
    at com.intellij.codeInsight.daemon.impl.LineMarkersPass.a(LineMarkersPass.java:174)
    at com.intellij.codeInsight.daemon.impl.LineMarkersPass.a(LineMarkersPass.java:96)
    at com.intellij.codeInsight.daemon.impl.Divider.divideInsideAndOutsideInOneRoot(Divider.java:80)
    at com.intellij.codeInsight.daemon.impl.LineMarkersPass.doCollectInformation(LineMarkersPass.java:91)
    at com.intellij.codeHighlighting.TextEditorHighlightingPass.collectInformation(TextEditorHighlightingPass.java:69)
    at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.c(PassExecutorService.java:423)
    at com.intellij.openapi.application.impl.ApplicationImpl.tryRunReadAction(ApplicationImpl.java:1161)
    at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.b(PassExecutorService.java:416)
    at com.intellij.openapi.progress.impl.CoreProgressManager.a(CoreProgressManager.java:580)
    at com.intellij.openapi.progress.impl.CoreProgressManager.executeProcessUnderProgress(CoreProgressManager.java:525)
    at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:85)
    at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.a(PassExecutorService.java:415)
    at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.d(PassExecutorService.java:391)
    at com.intellij.openapi.application.impl.ReadMostlyRWLock.executeByImpatientReader(ReadMostlyRWLock.java:147)
    at com.intellij.openapi.application.impl.ApplicationImpl.executeByImpatientReader(ApplicationImpl.java:222)
    at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.run(PassExecutorService.java:389)
    at com.intellij.concurrency.JobLauncherImpl$VoidForkJoinTask$1.exec(JobLauncherImpl.java:161)
    at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
    at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
    at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
    at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)

Thanks!
The NoSuchMethodError usually appears when you unzip new version over the previous one. It seems that something was not quite right with PyCharm during that.

ERROR - aemon.impl.PassExecutorService - one.util.streamex.StreamEx.nonNull()Lone/util/streamex/StreamEx; 
java.lang.NoSuchMethodError: one.util.streamex.StreamEx.nonNull()Lone/util/streamex/StreamEx;

All in all, I kindly ask you to reinstall PyCharm into an empty directory. So, completely uninstall it, download from https://www.jetbrains.com/pycharm/download and install. Please let me know if the problem remains.

Yes, that solved the problem! Thanks!