From 93ea163fa445b9c4b185b20f2a5c221081bff873 Mon Sep 17 00:00:00 2001 From: Michael Williamson Date: Sun, 1 Oct 2023 20:00:00 +0100 Subject: Check for duplicate cases --- .../org/shedlang/compiler/typechecker/TypeChecker.java | 9 +++++---- .../typechecker/errors/DuplicateWhenCaseError.java | 18 ++++++++++++++++++ 2 files changed, 23 insertions(+), 4 deletions(-) create mode 100644 src/main/java/org/shedlang/compiler/typechecker/errors/DuplicateWhenCaseError.java (limited to 'src/main/java') diff --git a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java index d38c5ac1..d11cf4c0 100644 --- a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java +++ b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java @@ -1156,18 +1156,19 @@ public class TypeChecker { var expressionTypeInfo = context.sumTypeInfo(expressionType, untyped.source()); var variantTypes = expressionTypeInfo.variants(); + var handledVariantTypes = new HashSet(); for (var typedCase : typedCases) { var caseType = typedCase.caseType().value(); if (!variantTypes.contains(caseType)) { throw new UnreachableWhenCaseError(caseType, typedCase.source()); } + if (handledVariantTypes.contains(caseType)) { + throw new DuplicateWhenCaseError(caseType, typedCase.source()); + } + handledVariantTypes.add(caseType); } - var handledVariantTypes = typedCases.stream() - .map(typedCase -> typedCase.caseType().value()) - .collect(Collectors.toSet()); - for (var variantType : variantTypes) { if (!handledVariantTypes.contains(variantType)) { throw new UnhandledVariantError(variantType, untyped.source()); diff --git a/src/main/java/org/shedlang/compiler/typechecker/errors/DuplicateWhenCaseError.java b/src/main/java/org/shedlang/compiler/typechecker/errors/DuplicateWhenCaseError.java new file mode 100644 index 00000000..6197479e --- /dev/null +++ b/src/main/java/org/shedlang/compiler/typechecker/errors/DuplicateWhenCaseError.java @@ -0,0 +1,18 @@ +package org.shedlang.compiler.typechecker.errors; + +import org.shedlang.compiler.errors.SourceError; +import org.shedlang.compiler.sources.Source; +import org.shedlang.compiler.types.Type; + +public class DuplicateWhenCaseError extends SourceError { + private final Type caseType; + + public DuplicateWhenCaseError(Type caseType, Source source) { + super("The case for " + caseType.describe() + " has already been handled", source); + this.caseType = caseType; + } + + public Type caseType() { + return caseType; + } +} -- cgit v1.2.3