[WIP] fix error reporting for a pattern variable + multiple patterns

Signed-off-by: David Thompson <[email protected]>
eclipse-jdt · Dec 13, 2023 · 6bc645b · 6bc645b
1 parent 6b8147e
commit 6bc645b
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Showing 3 changed files with 31 additions and 7 deletions.
diff --git a/...ipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/ast/CaseStatement.java b/...ipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/ast/CaseStatement.java
@@ -284,10 +284,14 @@ private Expression getFirstValidExpression(BlockScope scope, SwitchStatement swi
 			if (e instanceof Pattern) {
 				scope.problemReporter().validateJavaFeatureSupport(JavaFeature.PATTERN_MATCHING_IN_SWITCH,
 						e.sourceStart, e.sourceEnd);
-				if (this.constantExpressions.length > 1) {
-					scope.problemReporter().illegalCaseLabelWithMultiplePatterns(this.constantExpressions[1], this.constantExpressions[this.constantExpressions.length - 1]);
-					return e;
+				if (this.constantExpressions.length > 1 || e instanceof GuardedPattern gp && gp.patterns.length > 1) {
+					PatternVariableCounter myVisitor = new PatternVariableCounter();
+					this.traverse(myVisitor, scope);
+					if (myVisitor.numVars > 0) {
+						scope.problemReporter().illegalCaseLabelWithMultiplePatterns(this);
+					}
 				}
+				return e;
 			} else if (e instanceof NullLiteral) {
 				scope.problemReporter().validateJavaFeatureSupport(JavaFeature.PATTERN_MATCHING_IN_SWITCH,
 						e.sourceStart, e.sourceEnd);
@@ -559,4 +563,24 @@ public LocalDeclaration getLocalDeclaration() {
 	return patternVariableIntroduced;
 }
 
+private class PatternVariableCounter extends ASTVisitor {
+
+	public int numVars = 0;
+
+	@Override
+	public boolean visit(TypePattern pattern, BlockScope scope) {
+		if (pattern.local != null && (pattern.local.name.length != 1 || pattern.local.name[0] != '_') && !"\\u005F".equals(pattern.local.name.toString())) { //$NON-NLS-1$
+			this.numVars++;
+		}
+		return true;
+	}
+
+	@Override
+	public boolean visit(RecordPattern pattern, BlockScope scope) {
+		if (pattern.local != null && (pattern.local.name.length != 1 || pattern.local.name[0] != '_') && !"\\u005F".equals(pattern.local.name.toString())) { //$NON-NLS-1$
+			this.numVars++;
+		}
+		return true;
+	}
+}
 }
diff --git a/...dt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/problem/ProblemReporter.java b/...dt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/problem/ProblemReporter.java
@@ -12342,13 +12342,13 @@ public void illegalFallthroughFromAPattern(Statement statement) {
 		statement.sourceStart,
 		statement.sourceEnd);
 	}
-public void illegalCaseLabelWithMultiplePatterns(Expression secondPattern, Expression lastPattern) {
+public void illegalCaseLabelWithMultiplePatterns(Statement statement) {
 	this.handle(
 		IProblem.CaseLabelWithPatternMustHaveExactlyOnePattern,
 		NoArgument,
 		NoArgument,
-		secondPattern.sourceStart,
-		lastPattern.sourceEnd);
+		statement.sourceStart,
+		statement.sourceEnd);
 	}
 public void illegalCaseConstantCombination(Expression element) {
 	this.handle(

diff --git a/...jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/problem/messages.properties b/...jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/problem/messages.properties
@@ -1154,7 +1154,7 @@
 1916 = A case label guard cannot have a constant expression with value as 'false'
 1940 = Cannot infer record pattern types for {0}
 1941 = Syntax error, record patterns are not allowed here
-1942 = Case labels with a pattern must have only one pattern
+1942 = Case labels with a named pattern variable must have only one pattern
 
 
 1990 = Access to {1}({2}) from the type {0} is emulated by a synthetic accessor method