[patterns-record-deconstruction3] RFR: Fix NPE and exhaustivity bug in record patterns with nested primitive type patterns

[Aggelos Biboudis]

The following attempts to address two problems:

a) the crash should not happen (shown below)
b) the switch should be considered exhaustive (as in the equivalent with Integer)


public record R(int x) {}

public int test2(R r) {
    return switch (r) {
        case R(int x) -> 1; // crash while type-checking this in Flow
        // error: the switch expression does not cover all possible input values
    };
}


<details>
<summary>Stack trace</summary>


java.lang.NullPointerException: Cannot invoke "com.sun.tools.javac.code.Type.isPrimitive()" because "t" is null
        at jdk.compiler/com.sun.tools.javac.code.Types.eraseNotNeeded(Types.java:2394)
        at jdk.compiler/com.sun.tools.javac.code.Types.erasure(Types.java:2387)
        at jdk.compiler/com.sun.tools.javac.code.Symbol$ClassSymbol.erasure(Symbol.java:1354)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$AliveAnalyzer.coversDeconstructionStartingFromComponent(Flow.java:812)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$AliveAnalyzer.coveredSymbols(Flow.java:776)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$AliveAnalyzer.coveredSymbolsForCases(Flow.java:745)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$AliveAnalyzer.visitSwitchExpression(Flow.java:728)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCSwitchExpression.accept(JCTree.java:1385)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:447)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$AliveAnalyzer.visitReturn(Flow.java:977)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCReturn.accept(JCTree.java:1714)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:447)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$AliveAnalyzer.scanStat(Flow.java:507)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$AliveAnalyzer.scanStats(Flow.java:515)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$AliveAnalyzer.visitBlock(Flow.java:607)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:1092)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:447)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$AliveAnalyzer.scanStat(Flow.java:507)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$AliveAnalyzer.visitMethodDef(Flow.java:571)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:922)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:447)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$AliveAnalyzer.visitClassDef(Flow.java:551)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCClassDecl.accept(JCTree.java:820)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:447)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$AliveAnalyzer.analyzeTree(Flow.java:1039)
        at jdk.compiler/com.sun.tools.javac.comp.Flow$AliveAnalyzer.analyzeTree(Flow.java:1031)
        at jdk.compiler/com.sun.tools.javac.comp.Flow.analyzeTree(Flow.java:223)
        at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1377)
        at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1351)
        at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:946)
        at jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:317)
        at jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:176)
        at jdk.compiler/com.sun.tools.javac.Main.compile(Main.java:64)
        at jdk.compiler/com.sun.tools.javac.Main.main(Main.java:50)


</details>

-------------

Commit messages:
 - Fix NPE and exhaustivity bug in record patterns with nested primitive type patterns

Changes: https://git.openjdk.java.net/amber/pull/82/files
 Webrev: https://webrevs.openjdk.java.net/?repo=amber&pr=82&range=00
  Stats: 69 lines in 2 files changed: 67 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/amber/pull/82.diff
  Fetch: git fetch https://git.openjdk.java.net/amber pull/82/head:pull/82

PR: https://git.openjdk.java.net/amber/pull/82