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Add new error message for unreachable else prongs

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* Adds error message for types: enum, int and bool
* Adds compile error tests
This commit is contained in:
antlilja 2020-06-24 19:12:42 +02:00
parent e60be30824
commit dcc406deff
2 changed files with 113 additions and 3 deletions
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20
src/ir.cpp
View File

@ -28700,6 +28700,10 @@ static IrInstGen *ir_analyze_instruction_check_switch_prongs(IrAnalyze *ira,
buf_ptr(enum_field->name)));
}
}
} else if(!switch_type->data.enumeration.non_exhaustive && switch_type->data.enumeration.src_field_count == instruction->range_count) {
ir_add_error_node(ira, instruction->else_prong,
buf_sprintf("unreachable else prong, all cases already handled"));
return ira->codegen->invalid_inst_gen;
}
} else if (switch_type->id == ZigTypeIdErrorSet) {
if (!resolve_inferred_error_set(ira->codegen, switch_type, target_value->base.source_node)) {
@ -28808,16 +28812,20 @@ static IrInstGen *ir_analyze_instruction_check_switch_prongs(IrAnalyze *ira,
return ira->codegen->invalid_inst_gen;
}
}
if (instruction->else_prong == nullptr) {
BigInt min_val;
eval_min_max_value_int(ira->codegen, switch_type, &min_val, false);
BigInt max_val;
eval_min_max_value_int(ira->codegen, switch_type, &max_val, true);
if (!rangeset_spans(&rs, &min_val, &max_val)) {
bool handles_all_cases = rangeset_spans(&rs, &min_val, &max_val);
if (!handles_all_cases && instruction->else_prong == nullptr) {
ir_add_error(ira, &instruction->base.base, buf_sprintf("switch must handle all possibilities"));
return ira->codegen->invalid_inst_gen;
} else if(handles_all_cases && instruction->else_prong != nullptr) {
ir_add_error_node(ira, instruction->else_prong,
buf_sprintf("unreachable else prong, all cases already handled"));
return ira->codegen->invalid_inst_gen;
}
}
} else if (switch_type->id == ZigTypeIdBool) {
int seenTrue = 0;
int seenFalse = 0;
@ -28851,6 +28859,12 @@ static IrInstGen *ir_analyze_instruction_check_switch_prongs(IrAnalyze *ira,
ir_add_error(ira, &instruction->base.base, buf_sprintf("switch must handle all possibilities"));
return ira->codegen->invalid_inst_gen;
}
if(seenTrue == 1 && seenFalse == 1 && instruction->else_prong != nullptr) {
ir_add_error_node(ira, instruction->else_prong,
buf_sprintf("unreachable else prong, all cases already handled"));
return ira->codegen->invalid_inst_gen;
}
} else if (instruction->else_prong == nullptr) {
ir_add_error(ira, &instruction->base.base,
buf_sprintf("else prong required when switching on type '%s'", buf_ptr(&switch_type->name)));

96
test/compile_errors.zig
View File

@ -468,6 +468,102 @@ pub fn addCases(cases: *tests.CompileErrorContext) void {
"tmp.zig:12:5: error: switch on non-exhaustive enum must include `else` or `_` prong",
});
cases.add("switch expression - unreachable else prong (bool)",
\\fn foo(x: bool) void {
\\ switch (x) {
\\ true => {},
\\ false => {},
\\ else => {},
\\ }
\\}
\\export fn entry() usize { return @sizeOf(@TypeOf(foo)); }
, &[_][]const u8{
"tmp.zig:5:9: error: unreachable else prong, all cases already handled",
});
cases.add("switch expression - unreachable else prong (u1)",
\\fn foo(x: u1) void {
\\ switch (x) {
\\ 0 => {},
\\ 1 => {},
\\ else => {},
\\ }
\\}
\\export fn entry() usize { return @sizeOf(@TypeOf(foo)); }
, &[_][]const u8{
"tmp.zig:5:9: error: unreachable else prong, all cases already handled",
});
cases.add("switch expression - unreachable else prong (u2)",
\\fn foo(x: u2) void {
\\ switch (x) {
\\ 0 => {},
\\ 1 => {},
\\ 2 => {},
\\ 3 => {},
\\ else => {},
\\ }
\\}
\\export fn entry() usize { return @sizeOf(@TypeOf(foo)); }
, &[_][]const u8{
"tmp.zig:7:9: error: unreachable else prong, all cases already handled",
});
cases.add("switch expression - unreachable else prong (range u8)",
\\fn foo(x: u8) void {
\\ switch (x) {
\\ 0 => {},
\\ 1 => {},
\\ 2 => {},
\\ 3 => {},
\\ 4...255 => {},
\\ else => {},
\\ }
\\}
\\export fn entry() usize { return @sizeOf(@TypeOf(foo)); }
, &[_][]const u8{
"tmp.zig:8:9: error: unreachable else prong, all cases already handled",
});
cases.add("switch expression - unreachable else prong (range i8)",
\\fn foo(x: i8) void {
\\ switch (x) {
\\ -128...0 => {},
\\ 1 => {},
\\ 2 => {},
\\ 3 => {},
\\ 4...127 => {},
\\ else => {},
\\ }
\\}
\\export fn entry() usize { return @sizeOf(@TypeOf(foo)); }
, &[_][]const u8{
"tmp.zig:8:9: error: unreachable else prong, all cases already handled",
});
cases.add("switch expression - unreachable else prong (enum)",
\\const TestEnum = enum{ T1, T2 };
\\
\\fn err(x: u8) TestEnum {
\\ switch (x) {
\\ 0 => return TestEnum.T1,
\\ else => return TestEnum.T2,
\\ }
\\}
\\
\\fn foo(x: u8) void {
\\ switch (err(x)) {
\\ TestEnum.T1 => {},
\\ TestEnum.T2 => {},
\\ else => {},
\\ }
\\}
\\
\\export fn entry() usize { return @sizeOf(@TypeOf(foo)); }
, &[_][]const u8{
"tmp.zig:14:9: error: unreachable else prong, all cases already handled",
});
cases.addTest("@export with empty name string",
\\pub export fn entry() void { }
\\comptime {