Commit `e730172e47`

Andrew Kelley <andrew@ziglang.org>

2021-04-08 07:02:45

stage2: fix switch validation of handling all enum values

There were several problems, all fixed: * AstGen was storing field names as references to the original source code bytes. However, that data would be destroyed when the source file is updated. Now, it correctly stores the field names in the Decl arena for the enum. The same fix applies to error set field names. * Sema was missing a memset inside `analyzeSwitch`, leaving the "seen enum fields" array with undefined memory. Now that they are all properly set to null, the validation works. * Moved the "enum declared here" note to the end. It looked weird interrupting the notes for which enum values were missing.

master

1 parent b67378f

Changed files (3)

src

Module.zig

Sema.zig

test

stage2

cbe.zig

@@ -4582,28 +4582,39 @@ pub fn optimizeMode(mod: Module) std.builtin.Mode {
 /// Otherwise, returns a reference to the source code bytes directly.
 /// See also `appendIdentStr` and `parseStrLit`.
 pub fn identifierTokenString(mod: *Module, scope: *Scope, token: ast.TokenIndex) InnerError![]const u8 {
-    return mod.identifierTokenStringTreeArena(scope, token, scope.tree(), scope.arena());
+    const tree = scope.tree();
+    const token_tags = tree.tokens.items(.tag);
+    assert(token_tags[token] == .identifier);
+    const ident_name = tree.tokenSlice(token);
+    if (!mem.startsWith(u8, ident_name, "@")) {
+        return ident_name;
+    }
+    var buf: ArrayListUnmanaged(u8) = .{};
+    defer buf.deinit(mod.gpa);
+    try parseStrLit(mod, scope, token, &buf, ident_name, 1);
+    const duped = try scope.arena().dupe(u8, buf.items);
+    return duped;
 }
 
 /// `scope` is only used for error reporting.
+/// The string is stored in `arena` regardless of whether it uses @"" syntax.
 pub fn identifierTokenStringTreeArena(
     mod: *Module,
     scope: *Scope,
     token: ast.TokenIndex,
     tree: *const ast.Tree,
     arena: *Allocator,
-) InnerError![]const u8 {
+) InnerError![]u8 {
     const token_tags = tree.tokens.items(.tag);
     assert(token_tags[token] == .identifier);
     const ident_name = tree.tokenSlice(token);
     if (!mem.startsWith(u8, ident_name, "@")) {
-        return ident_name;
+        return arena.dupe(u8, ident_name);
     }
     var buf: ArrayListUnmanaged(u8) = .{};
     defer buf.deinit(mod.gpa);
     try parseStrLit(mod, scope, token, &buf, ident_name, 1);
-    const duped = try arena.dupe(u8, buf.items);
-    return duped;
+    return arena.dupe(u8, buf.items);
 }
 
 /// Given an identifier token, obtain the string for it (possibly parsing as a string

@@ -2789,6 +2789,8 @@ fn analyzeSwitch(
             var seen_fields = try gpa.alloc(?AstGen.SwitchProngSrc, operand.ty.enumFieldCount());
             defer gpa.free(seen_fields);
 
+            mem.set(?AstGen.SwitchProngSrc, seen_fields, null);
+
             var extra_index: usize = special.end;
             {
                 var scalar_i: u32 = 0;
@@ -2849,12 +2851,6 @@ fn analyzeSwitch(
                                 .{},
                             );
                             errdefer msg.destroy(sema.gpa);
-                            try mod.errNoteNonLazy(
-                                operand.ty.declSrcLoc(),
-                                msg,
-                                "enum '{}' declared here",
-                                .{operand.ty},
-                            );
                             for (seen_fields) |seen_src, i| {
                                 if (seen_src != null) continue;
 
@@ -2865,10 +2861,16 @@ fn analyzeSwitch(
                                     &block.base,
                                     src,
                                     msg,
-                                    "unhandled enumeration value: '{s}",
+                                    "unhandled enumeration value: '{s}'",
                                     .{field_name},
                                 );
                             }
+                            try mod.errNoteNonLazy(
+                                operand.ty.declSrcLoc(),
+                                msg,
+                                "enum '{}' declared here",
+                                .{operand.ty},
+                            );
                             break :msg msg;
                         };
                         return mod.failWithOwnedErrorMsg(&block.base, msg);

@@ -702,6 +702,21 @@ pub fn addCases(ctx: *TestContext) !void {
             ":3:15: error: enum 'E' has no tag with value 3",
             ":1:11: note: enum declared here",
         });
+
+        case.addError(
+            \\const E = enum { a, b, c };
+            \\export fn foo() void {
+            \\    var x: E = .a;
+            \\    switch (x) {
+            \\        .a => {},
+            \\        .c => {},
+            \\    }
+            \\}
+        , &.{
+            ":4:5: error: switch must handle all possibilities",
+            ":4:5: note: unhandled enumeration value: 'b'",
+            ":1:11: note: enum 'E' declared here",
+        });
     }
 
     ctx.c("empty start function", linux_x64,

Commit e730172e47

Commit `e730172e47`