alternate implementation of previous commit

This strategy adds another field to the SwitchBr instruction,
which is the result of the CheckSwitchProngs instruction. The
type of the result is void, and is unused, except that the SwitchBr
instruction will not perform analysis if the CheckSwitchProngs
instruction did not pass analysis. This allows the CheckSwitchProngs
instruction to do implicit casting for its type checking, while
preventing duplicate compile error messages.

1 files changed, 27 insertions, 17 deletions

diff --git a/src/ir.cpp b/src/ir.cpp
index 37d673bbd7..204ebb332a 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -1719,7 +1719,8 @@ static IrInstruction *ir_build_ctz_from(IrBuilder *irb, IrInstruction *old_instr
 }
 
 static IrInstruction *ir_build_switch_br(IrBuilder *irb, Scope *scope, AstNode *source_node, IrInstruction *target_value,
-        IrBasicBlock *else_block, size_t case_count, IrInstructionSwitchBrCase *cases, IrInstruction *is_comptime)
+        IrBasicBlock *else_block, size_t case_count, IrInstructionSwitchBrCase *cases, IrInstruction *is_comptime,
+        IrInstruction *switch_prongs_void)
 {
     IrInstructionSwitchBr *instruction = ir_build_instruction<IrInstructionSwitchBr>(irb, scope, source_node);
     instruction->base.value.type = irb->codegen->builtin_types.entry_unreachable;
@@ -1729,10 +1730,12 @@ static IrInstruction *ir_build_switch_br(IrBuilder *irb, Scope *scope, AstNode *
     instruction->case_count = case_count;
     instruction->cases = cases;
     instruction->is_comptime = is_comptime;
+    instruction->switch_prongs_void = switch_prongs_void;
 
     ir_ref_instruction(target_value, irb->current_basic_block);
     if (is_comptime) ir_ref_instruction(is_comptime, irb->current_basic_block);
     ir_ref_bb(else_block);
+    if (switch_prongs_void) ir_ref_instruction(switch_prongs_void, irb->current_basic_block);
 
     for (size_t i = 0; i < case_count; i += 1) {
         ir_ref_instruction(cases[i].value, irb->current_basic_block);
@@ -1744,10 +1747,10 @@ static IrInstruction *ir_build_switch_br(IrBuilder *irb, Scope *scope, AstNode *
 
 static IrInstruction *ir_build_switch_br_from(IrBuilder *irb, IrInstruction *old_instruction,
         IrInstruction *target_value, IrBasicBlock *else_block, size_t case_count,
-        IrInstructionSwitchBrCase *cases, IrInstruction *is_comptime)
+        IrInstructionSwitchBrCase *cases, IrInstruction *is_comptime, IrInstruction *switch_prongs_void)
 {
     IrInstruction *new_instruction = ir_build_switch_br(irb, old_instruction->scope, old_instruction->source_node,
-            target_value, else_block, case_count, cases, is_comptime);
+            target_value, else_block, case_count, cases, is_comptime, switch_prongs_void);
     ir_link_new_instruction(new_instruction, old_instruction);
     return new_instruction;
 }
@@ -6035,13 +6038,13 @@ static IrInstruction *ir_gen_switch_expr(IrBuilder *irb, Scope *scope, AstNode *
 
     }
 
-    ir_build_check_switch_prongs(irb, scope, node, target_value, check_ranges.items, check_ranges.length,
+    IrInstruction *switch_prongs_void = ir_build_check_switch_prongs(irb, scope, node, target_value, check_ranges.items, check_ranges.length,
             else_prong != nullptr);
 
     if (cases.length == 0) {
         ir_build_br(irb, scope, node, else_block, is_comptime);
     } else {
-        ir_build_switch_br(irb, scope, node, target_value, else_block, cases.length, cases.items, is_comptime);
+        ir_build_switch_br(irb, scope, node, target_value, else_block, cases.length, cases.items, is_comptime, switch_prongs_void);
     }
 
     if (!else_prong) {
@@ -6692,7 +6695,7 @@ static IrInstruction *ir_gen_await_expr(IrBuilder *irb, Scope *parent_scope, Ast
     cases[1].value = ir_build_const_u8(irb, parent_scope, node, 1);
     cases[1].block = cleanup_block;
     ir_build_switch_br(irb, parent_scope, node, suspend_code, irb->exec->coro_suspend_block,
-            2, cases, const_bool_false);
+            2, cases, const_bool_false, nullptr);
 
     ir_set_cursor_at_end_and_append_block(irb, cleanup_block);
     ir_gen_defers_for_block(irb, parent_scope, outer_scope, true);
@@ -6773,7 +6776,7 @@ static IrInstruction *ir_gen_suspend(IrBuilder *irb, Scope *parent_scope, AstNod
     cases[1].value = ir_mark_gen(ir_build_const_u8(irb, parent_scope, node, 1));
     cases[1].block = cleanup_block;
     ir_mark_gen(ir_build_switch_br(irb, parent_scope, node, suspend_code, irb->exec->coro_suspend_block,
-            2, cases, const_bool_false));
+            2, cases, const_bool_false, nullptr));
 
     ir_set_cursor_at_end_and_append_block(irb, cleanup_block);
     ir_gen_defers_for_block(irb, parent_scope, outer_scope, true);
@@ -7078,7 +7081,7 @@ bool ir_gen(CodeGen *codegen, AstNode *node, Scope *scope, IrExecutable *ir_exec
         cases[0].block = invalid_resume_block;
         cases[1].value = ir_build_const_u8(irb, scope, node, 1);
         cases[1].block = irb->exec->coro_final_cleanup_block;
-        ir_build_switch_br(irb, scope, node, suspend_code, irb->exec->coro_suspend_block, 2, cases, const_bool_false);
+        ir_build_switch_br(irb, scope, node, suspend_code, irb->exec->coro_suspend_block, 2, cases, const_bool_false, nullptr);
 
         ir_set_cursor_at_end_and_append_block(irb, irb->exec->coro_suspend_block);
         ir_build_coro_end(irb, scope, node);
@@ -15297,6 +15300,13 @@ static TypeTableEntry *ir_analyze_instruction_switch_br(IrAnalyze *ira,
     if (type_is_invalid(target_value->value.type))
         return ir_unreach_error(ira);
 
+    if (switch_br_instruction->switch_prongs_void != nullptr) {
+        if (type_is_invalid(switch_br_instruction->switch_prongs_void->other->value.type)) {
+            return ir_unreach_error(ira);
+        }
+    }
+
+
     size_t case_count = switch_br_instruction->case_count;
 
     bool is_comptime;
@@ -15387,7 +15397,7 @@ static TypeTableEntry *ir_analyze_instruction_switch_br(IrAnalyze *ira,
 
     IrBasicBlock *new_else_block = ir_get_new_bb(ira, switch_br_instruction->else_block, &switch_br_instruction->base);
     ir_build_switch_br_from(&ira->new_irb, &switch_br_instruction->base,
-            target_value, new_else_block, case_count, cases, nullptr);
+            target_value, new_else_block, case_count, cases, nullptr, nullptr);
     return ir_finish_anal(ira, ira->codegen->builtin_types.entry_unreachable);
 }
 
@@ -19136,27 +19146,27 @@ static TypeTableEntry *ir_analyze_instruction_check_switch_prongs(IrAnalyze *ira
             IrInstruction *start_value = range->start->other;
             if (type_is_invalid(start_value->value.type))
                 return ira->codegen->builtin_types.entry_invalid;
+            IrInstruction *casted_start_value = ir_implicit_cast(ira, start_value, switch_type);
+            if (type_is_invalid(casted_start_value->value.type))
+                return ira->codegen->builtin_types.entry_invalid;
 
             IrInstruction *end_value = range->end->other;
             if (type_is_invalid(end_value->value.type))
                 return ira->codegen->builtin_types.entry_invalid;
+            IrInstruction *casted_end_value = ir_implicit_cast(ira, end_value, switch_type);
+            if (type_is_invalid(casted_end_value->value.type))
+                return ira->codegen->builtin_types.entry_invalid;
 
-            ConstExprValue *start_val = ir_resolve_const(ira, start_value, UndefBad);
+            ConstExprValue *start_val = ir_resolve_const(ira, casted_start_value, UndefBad);
             if (!start_val)
                 return ira->codegen->builtin_types.entry_invalid;
 
-            ConstExprValue *end_val = ir_resolve_const(ira, end_value, UndefBad);
+            ConstExprValue *end_val = ir_resolve_const(ira, casted_end_value, UndefBad);
             if (!end_val)
                 return ira->codegen->builtin_types.entry_invalid;
 
-            if (start_val->type->id == TypeTableEntryIdEnum)
-                return ira->codegen->builtin_types.entry_invalid;
             assert(start_val->type->id == TypeTableEntryIdInt || start_val->type->id == TypeTableEntryIdComptimeInt);
-
-            if (end_val->type->id == TypeTableEntryIdEnum)
-                return ira->codegen->builtin_types.entry_invalid;
             assert(end_val->type->id == TypeTableEntryIdInt || end_val->type->id == TypeTableEntryIdComptimeInt);
-
             AstNode *prev_node = rangeset_add_range(&rs, &start_val->data.x_bigint, &end_val->data.x_bigint,
                     start_value->source_node);
             if (prev_node != nullptr) {