diff --git a/lib/cretonne/meta/gen_binemit.py b/lib/cretonne/meta/gen_binemit.py
index 8c591f0513..c3d1b18e86 100644
--- a/lib/cretonne/meta/gen_binemit.py
+++ b/lib/cretonne/meta/gen_binemit.py
@@ -133,17 +133,21 @@ def gen_isa(isa, fmt):
             '''.format(isa.name))
     if len(isa.all_recipes) == 0:
         # No encoding recipes: Emit a stub.
-        with fmt.indented(
-                'pub fn emit_inst<CS: CodeSink + ?Sized>'
-                '(func: &Function, inst: Inst, '
-                '_divert: &mut RegDiversions, _sink: &mut CS) {', '}'):
+        with fmt.indented('pub fn emit_inst<CS: CodeSink + ?Sized>('):
+            fmt.line('func: &Function,')
+            fmt.line('inst: Inst,')
+            fmt.line('_divert: &mut RegDiversions,')
+            fmt.line('_sink: &mut CS,')
+        with fmt.indented(') {', '}'):
             fmt.line('bad_encoding(func, inst)')
     else:
         fmt.line('#[allow(unused_variables, unreachable_code)]')
-        with fmt.indented(
-                'pub fn emit_inst<CS: CodeSink + ?Sized>'
-                '(func: &Function, inst: Inst, '
-                'divert: &mut RegDiversions, sink: &mut CS) {', '}'):
+        with fmt.indented('pub fn emit_inst<CS: CodeSink + ?Sized>('):
+            fmt.line('func: &Function,')
+            fmt.line('inst: Inst,')
+            fmt.line('divert: &mut RegDiversions,')
+            fmt.line('sink: &mut CS,')
+        with fmt.indented(') {', '}'):
             fmt.line('let encoding = func.encodings[inst];')
             fmt.line('let bits = encoding.bits();')
             with fmt.indented('match func.encodings[inst].recipe() {', '}'):
@@ -151,7 +155,7 @@ def gen_isa(isa, fmt):
                     fmt.comment(recipe.name)
                     with fmt.indented('{} => {{'.format(i), '}'):
                         gen_recipe(recipe, fmt)
-                fmt.line('_ => {}')
+                fmt.line('_ => {},')
             # Allow for un-encoded ghost instructions.
             # Verifier checks the details.
             with fmt.indented('if encoding.is_legal() {', '}'):
diff --git a/lib/cretonne/meta/gen_instr.py b/lib/cretonne/meta/gen_instr.py
index b004aaadf1..4c537acf12 100644
--- a/lib/cretonne/meta/gen_instr.py
+++ b/lib/cretonne/meta/gen_instr.py
@@ -97,7 +97,7 @@ def gen_arguments_method(fmt, is_mut):
                     capture = 'ref {}args, '.format(mut)
                     arg = 'args'
                 fmt.line(
-                        '{} {{ {} .. }} => {},'
+                        '{} {{ {}.. }} => {},'
                         .format(n, capture, arg))
 
 
@@ -271,7 +271,7 @@ def gen_opcodes(groups, fmt):
                                     'Opcode::{} => true,',
                                     i.camel_name, i.name)
 
-                    fmt.line('_ => false')
+                    fmt.line('_ => false,')
 
     # Generate a private opcode_format table.
     with fmt.indented(
@@ -352,7 +352,7 @@ def gen_typesets_table(fmt, type_sets):
     fmt.comment('Table of value type sets.')
     assert len(type_sets.table) <= typeset_limit, "Too many type sets"
     with fmt.indented(
-            'const TYPE_SETS : [ir::instructions::ValueTypeSet; {}] = ['
+            'const TYPE_SETS: [ir::instructions::ValueTypeSet; {}] = ['
             .format(len(type_sets.table)), '];'):
         for ts in type_sets.table:
             with fmt.indented('ir::instructions::ValueTypeSet {', '},'):
@@ -385,7 +385,7 @@ def gen_type_constraints(fmt, instrs):
 
     fmt.comment('Table of opcode constraints.')
     with fmt.indented(
-            'const OPCODE_CONSTRAINTS : [OpcodeConstraints; {}] = ['
+            'const OPCODE_CONSTRAINTS: [OpcodeConstraints; {}] = ['
             .format(len(instrs)), '];'):
         for i in instrs:
             # Collect constraints for the value results, not including
@@ -442,7 +442,7 @@ def gen_type_constraints(fmt, instrs):
 
     fmt.comment('Table of operand constraint sequences.')
     with fmt.indented(
-            'const OPERAND_CONSTRAINTS : [OperandConstraint; {}] = ['
+            'const OPERAND_CONSTRAINTS: [OperandConstraint; {}] = ['
             .format(len(operand_seqs.table)), '];'):
         for c in operand_seqs.table:
             fmt.line('OperandConstraint::{},'.format(c))
diff --git a/lib/cretonne/meta/gen_settings.py b/lib/cretonne/meta/gen_settings.py
index 223e33f478..9f80a391ff 100644
--- a/lib/cretonne/meta/gen_settings.py
+++ b/lib/cretonne/meta/gen_settings.py
@@ -62,7 +62,7 @@ def gen_getter(setting, sgrp, fmt):
                     .format(setting.byte_offset), '}'):
                 for i, v in enumerate(setting.values):
                     fmt.line('{} => {}::{},'.format(i, ty, camel_case(v)))
-                fmt.line('_ => panic!("Invalid enum value")')
+                fmt.line('_ => panic!("Invalid enum value"),')
     else:
         raise AssertionError("Unknown setting kind")
 
@@ -197,7 +197,7 @@ def gen_template(sgrp, fmt):
         fmt.line('enumerators: &ENUMERATORS,')
         fmt.line('hash_table: &HASH_TABLE,')
         vs = ', '.join('{:#04x}'.format(x) for x in v)
-        fmt.line('defaults: &[ {} ],'.format(vs))
+        fmt.line('defaults: &[{}],'.format(vs))
         fmt.line('presets: &PRESETS,')
 
     fmt.doc_comment(
diff --git a/lib/cretonne/meta/isa/riscv/recipes.py b/lib/cretonne/meta/isa/riscv/recipes.py
index 6ce25af6fc..8cbbd40a80 100644
--- a/lib/cretonne/meta/isa/riscv/recipes.py
+++ b/lib/cretonne/meta/isa/riscv/recipes.py
@@ -131,11 +131,13 @@ Iret = EncRecipe(
         emit='''
         // Return instructions are always a jalr to %x1.
         // The return address is provided as a special-purpose link argument.
-        put_i(bits,
-              1, // rs1 = %x1
-              0, // no offset.
-              0, // rd = %x0: no address written.
-              sink);
+        put_i(
+            bits,
+            1, // rs1 = %x1
+            0, // no offset.
+            0, // rd = %x0: no address written.
+            sink,
+        );
         ''')
 
 # I-type encoding for `jalr` as an indirect call.
@@ -143,11 +145,13 @@ Icall = EncRecipe(
         'Icall', IndirectCall, size=4, ins=GPR, outs=(),
         emit='''
         // Indirect instructions are jalr with rd=%x1.
-        put_i(bits,
-              in_reg0,
-              0, // no offset.
-              1, // rd = %x1: link register.
-              sink);
+        put_i(
+            bits,
+            in_reg0,
+            0, // no offset.
+            1, // rd = %x1: link register.
+            sink,
+        );
         ''')